Text and photos copyright © 2018 Steve D’Antonio Marine Consulting, Inc.

From the Masthead

It’s happened on countless occasions, most recently just a few weeks ago while on a sea trial out of a South Florida inlet.  The conditions were bumpy, 6 foot seas with a short period, (along with the most vivid case of sea smoke I’ve ever encountered in southern latitudes, the air temperature was in the low 40s, see photo).  Ideal as far as sea trials go.  The pilothouse was a busy place; the buyer, helmsman, mate, brokers, surveyors, mechanics etc. were all coming and going.  The helmsman was concentrating on safely piloting the vessel when it happened, an alarm began to sound, a moderately low level rhythmic beep, beep, beep.  Pilothouse alarms are common on large, complex vessels of this sort, and so initially no one was particularly concerned.   However, the longer it went on the more folks began to notice.  Predictably someone eventually said, “What’s that for”.  The response was silence, no one knew.   Eventually the source was identified, and it was not critical, however, how is one to know?

A few years ago, while making an early spring passage from the UK to Germany aboard a new vessel, through conditions that were positively horrendous, the windshield looked like the proverbial washing machine, a similar event occurred.  I was on watch alone, the other two crew members had gone off duty thirty minutes prior and were getting some much-needed rest.  As I sat in the helm seat hanging on to its arms, contemplating the next wave impact, an alarm sounded.  This time, however it was different, the vessel’s central monitoring system flashed a large red bar across the bottom of the screen which said, “FIRE”.  Indeed, this was a genuinely serious issue and there was no mistaking it.  As it turned out, a dashboard monitor had overheated and began to emit smoke behind the helm station, where, thankfully, a smoke detector had been installed.  As it turned out the problem was not serious, and shutting down the monitor resolved the problem for the moment.

I’ve been asked by boat owners and buyers on countless occasions, if there is a means by which disparate pilothouse instruments could be interfaced, strictly to create a central alarm panel.  It would simply consist of a panel with the names of various components, AUTOPILOT; STABILIZERS; DEPTH; ENGINE etc, each with its own pilot light.  When an alarm sounded, the light adjacent to the device name would illuminate.  It sounds like a simple concept, and yet to the best of my knowledge none exists.  While many components can be interfaced via an NMEA 2000 or N2K network, not every component has this option and even when it does, getting a simple alarm indication on a central display can be challenging.  It seems the best option involves the use of a vessel-wide monitoring system such as a Maretron or BÖNING, however, while I like these systems they are costly and complex and not easily added to an existing vessel, and they are probably overkill for the goal of obtaining nothing more than a central alarm system.

Thus, I’m throwing down the gauntlet, if a marine electronics manufacturer, or creative technician can come up with such a system, analogue or digital, and relatively easy to install, I suspect he or she would have no shortage of interested parties.

This month’s eMagazine feature article covers the subject of coaxial cable performance and selection.  I hope you find it both interesting and useful.

The Low Down on Coaxial Cables and Connectors

Coaxial cable is available in a range of sizes, types, and performance characteristics.  Cost is usually a good indicator of performance and quality. 

The axiom out of sight out of mind applies as much aboard boats as anywhere else and in my experience it is especially applicable to marine electrical and electronic systems.   Because flaws, faults and defects are not readily apparent in these systems, they tend to go unaddressed.  The issues are, however, often quite noticeable when one knows how and where to look.

Coaxial Cable 101

Take for instance the manner in which a radio transceiver ( a transceiver is simply a combined receiver and transmitter) or receiver such as a VHF, SSB, AIS, shortwave, GPS, cell phone, cellular or Wi-Fi booster is wired to its respective antenna.  With the exception of some Wi-Fi boosters, which use a data cable, in all of these cases the cable used for this application is known as coaxial, which is a reference to the inner and outer conductors sharing the same axis.  The inner core, it’s typically a series of coarse strands but may also be a single conductor, carries the signal while an outer tube-like grounded conductor, usually a braid or foil or combination of the two (the greater the coverage of the shield the better, it’s often expressed as a percent that’s typically between 65% and 95%), reduces loss or degradation of the signal while minimizing electromagnetic interference from other radio signals or electrical equipment.  Many homes in the US, Canada, Europe and elsewhere in the developed world have coaxial cable for television and in many cases internet applications, connecting external antennas, satellite dishes, cable TV, and internet service providers to television sets and routers in homes and offices.

The connection between an SSB tuner and the antenna relies on GTO cable, which is vastly different than coaxial cable.  It acts as part of the antenna, and the terminal on the tuner, shown here, should be insulated.

If an ordinary wire is used rather than a coaxial cable for the transmission of radio frequency, or “RF”, energy it will simply act like an antenna, transmitting signals inside the vessel (which often leads to interference with and malfunctioning of other equipment), losing those signals as they are received and sent to and from the radio and antenna.  The shield is grounded at the transceiver end and thereby keeps the signal contained within the cable and prevents the introduction of unwanted signals into the center core conductor.  The spacing between the shield and the center core is critical and must be kept constant.  Kinking, crushing or sharply bending (most coaxial manufacturers specify a minimum bend radius) a coaxial cable compromises this critical spacing, which will degrade the signal.  Removing the dielectric insulator, the material found between the shield and the center core and terminating or splicing the core and shield “manually”, like ordinary wires, also leads to signal loss and increases the likelihood of interference both to and from the cable.

Sharp bends stress coaxial cable and can affect performance, they should be avoided.

Additionally, any abrupt change to the dimensions or spacing of the core and shield causes a reflection of the radio waves back to the source, to the transmitter.  This phenomenon, known as standing wave, creates a bottle neck, through which signals have difficulty passing, ultimately degrading the transmission quality.  Standing wave is measured as a ratio, known as standing wave ratio or SWR.  In short, it’s a measure of the difference between the maximum RF and the minimum RF voltage along the cable.  What’s most important about this ratio is ensuring that it’s kept low.  If there are no reflecting sources, if the cable is uniform and properly terminated, then the SWR would, ideally, be 1:1.

Another  factor that affects SWR is the matching of the impedance or resistance of the cable, this is a function of the cable’s dimensions and construction, to the impedance of the devices to which it’s connected; the transceiver or receiver and the antenna.  When the two are matched, they appear “transparent” to the RF signal and reflections and thus SWR are minimized.  Most coaxial cables used for radio transmission and reception aboard have an impedance of 50 ohms, while some, such as those used for television, are 75 ohms.  It’s important that the correct impedance cable be used and that it match the antenna and transceiver/receiver in order to ensure a low SWR.

Cable Selection

A variety of coaxial cables are available, in a host of sizes, with a range of loss characteristics, and impedances as well as a range of quality and associated expense from many different manufacturers.  Selection can be truly confusing even for professionals.

Proper cable selection depends primarily on a few details.  Chief among these are the recommendations of the equipment manufacturer.  In many cases, the maker of a radio will very clearly spell out the type of cable that should, depending upon the installation conditions, be used.  In the absence of that information, however, additional criteria must be relied upon.  Begin with determining the frequency range of the equipment.  This isn’t as difficult as it sounds.  In general terms, the most commonly used radio equipment falls in to a few well-defined frequency ranges, the most common and those relying on conventional coaxial cable are HF, SSB or shortwave, which operates between 3 and 30 MHz (an abbreviation for mega Hertz, or million Hertz, named after German physicist Heinrich Hertz who made significant contributions in the study of electromagnetism, it’s a measure of the number oscillations that occur per second which defines the radio frequency, in the past it was often referred to by the designation it replaced, cycles).  Marine VHF radio (and AIS) frequency is between 156 MHz and 158 MHZ and cellular frequencies are between about 850 MHz and 1900 MHz GPS satellites, and receivers operate at about 1500 MHz  Wi-Fi tops the list at between 2.5 and 5 GHz or giga-Hertz, which is the abbreviation for a billion Hertz.

The reason the frequency is important where cable selection is concerned is the attendant inefficiency or loss; the higher the frequency the greater the potential for loss from the cable.  Thus, several protocols can be derived from this truism.  Gear that operates at higher frequency must use higher efficiency, lower loss cable (and connectors, more on those below) and the runs between the receiver/transceiver should be kept as short as possible, necessitating even lower loss cable.   Of course this is true of all radio equipment, low loss cable and short runs are always desirable, however, it becomes more critical for VHF, AIS and cellular/Wi-Fi gear.  Although the loss characteristics are not as great where SSB/HF/shortwave are concerned, these installations still can and regularly do suffer from poor cable selection and unnecessarily long runs or a combination of the two.

Heavy, extra low loss cable, like that shown here, is well-suited for longer runs and higher frequencies.  It’s bulky but worth the effort.

As in illustration of how coaxial cable loss may affect transmission characteristics I’ll share a scenario I frequently encounter aboard vessels I inspect.  A VHF radio is installed in the pilot house aboard a 52-footer.   The cable run from the radio to the antenna, which is mounted on an arch or mast above the fly bridge, is 40 feet, assuming the installer hasn’t left an additional 20 feet of cable coiled up beneath the helm, which is highly undesirable and not uncommon.  The cable “run” is a measure of actual linear feet rather than an imaginary straight line drawn between the antenna and transceiver.  The output of the VHF radio is 25 watts (or 1 watt on specified channels) and the cable that’s been chosen, for this example, is a common type referred to as RG 58U, is about 3/16 inch (4.7mm) in diameter, pretty gossamer.  The actual power output at the antenna-end of the cable is just 13.4 watts, or a reduction of 45%, the rest of the power has been “lost” in the cable run.  It’s important to remember, the type and location of the antenna has a considerable effect on the efficiency of the transmitted signal, however, in plain terms, the lower the cable’s loss, the better and the more power the antenna receives the greater its transmission (and reception) characteristics.

If, on the other hand, a more efficient cable is chosen, say RG-8X, a common, ¼ inch (6.3mm) diameter, higher efficiency lower loss cable, which is often used for VHF installations, with all other factors remaining the same, the wattage reaching the antenna increases to 16.9 or a reduction of 32%.  If a still lower loss cable is used, the Cadillac of coaxial cables and my personal preference, Times Microwave LMR 400, can be utilized, this cable is a hefty 13.32 inch (10mm) in diameter, the reduction in radio energy reaching the antenna is a scant 12%.  Now, imagine the same circumstances placed on a cellular coaxial and antenna installation. Recall that cell frequencies are many times higher (with loss many times greater) than those of VHF and their output power many times lower, and it’s easy to see how the performance can be significantly degraded.

Exposed coaxial terminals will corrode.  In wet locations, including bilges, they should be installed using a light film of dielectric grease, and then covered with heat shrink tubing or high quality electrical tape; if on weather decks these must be UV resistant.

As you can see, the price that is paid for low loss; essentially cable bulkiness (and commensurate expense) is very clear.  The same calculations can be carried out for other cables and transmission frequencies with some very startling results.  The high frequency of cell phones, for instance, coupled with their low output power of between a quarter and three watts (the latter for boosters) makes for very special coaxial cable requirements.  In this case low loss cable should always be used even for relatively short runs.  The same holds true for Wi-Fi applications and, once again, every effort should be made to keep these cable runs as short as possible.

Once a cable’s shield is exposed, and it has been exposed to the elements, it is almost certainly compromised.

By the same token, even though SSB frequencies are lower and thus less loss prone, the often long run between the transceiver and the antenna and/or tuner means these installations call for low loss cable.  Additionally, in spite of the fact that their output power is considerably higher, up to 150 watts, the range over which they transmit is significant, hundreds or thousands of miles and as such it’s worth the effort and expense of ensuring the antenna receives as many watts of transmission power as possible.  Thus, using RG8X for a 50-foot run between a helm-mounted transceiver and the lazarette mounted tuner would result in an 18% power loss, assuming other common loss or SWR matching inefficiency factors.  This may not seem like a significant number, however, once again, when the transmission distance is considered it may mean the difference between a voice communication that’s intelligibly received and one that’s simply ignored because it’s garbled, faint or static-laden.  If the Times Microwave LMR 400 cable is used the loss becomes just 7%.  Every watt counts when it comes to marine communications so don’t let an installer tell you it’s “fine” or “there’s no real difference”, insist on low loss cable.   Another note on SSBs, most utilize a separate antenna tuner that is or should be located close to the antenna, it’s connected to the transceiver using coaxial cable while the connection between the tuner and the antenna utilizes another specialized, non-shielded cable referred to as GTO-15.  Although it resembles GTO cable, coaxial cable should not be confused with or used in its place, GTO is actually a transmitting part of the antenna, and thus is thus it should not be run inside accommodation spaces.

When choosing coaxial cable, in addition to the criteria mentioned above, ensure that it’s suitable for marine applications.  Fortunately, this isn’t simply a way for manufacturers and retailers to charge more for a product that’s no different than other land-based versions.  Most marine-grade cable utilizes corrosion resistant tinned conductors.  The cable’s jacket may be white or black, although proprietary marine coaxial tends to be white.  The name of the manufacturer as well as the cable type, RG 8X or LMR 400 for instance should be clearly printed on the jacket.  Having said that, the lowest-loss cable may not be marine rated; in my opinion low loss trumps corrosion resistance.

While tinned, corrosion resistant conductors are desirable, some very low loss cable is not available in this format.  Given the choice, choose low loss over corrosion resistance.  Careful attention should be paid to waterproofing installations regardless of the type of cable that is used.

Connectors

The other half of the coaxial cable equation involves the type and method of attachment of connectors.  Coaxial cables require special terminals that must be installed following clearly defined techniques, the transgression of which nearly always results in diminished performance, or worse, no performance at all.

A selection of coaxial terminals, each specifically designed for a particular cable type.

The volume of connectors available is nearly endless and quality of materials and construction covers a broad spectrum, from economy to gold plated, literally.  Connectors should be purchased from name-brand respected manufacturers (often, higher quality connectors are embossed with the manufacturer’s name) such as Amphenol, they invented modern coaxial connectors, Ancor, Shakespeare, Times Microwave and others.  High quality coaxial connectors are made of brass or beryllium copper with silver and/or tin plating and in some cases gold plating (the conductivity of silver is higher than gold and even higher than copper; however, gold does not tarnish, although silver’s silver oxide “tarnish” is conductive).  The insulating material between the center core and the outer shield should be capable of withstanding substantial heat for connectors that are designed to be soldered, at least 300°F.  Lower quality, and low cost, connectors often utilize a form of plastic whose melting temperature is well below this threshold, which makes a solid solder joint difficult to achieve without damaging this insulator material. Check these connector specifications before purchasing or specifying for others.

Failing to use solder on coaxial terminals that are designed to be soldered virtually guarantees poor performance.

Much like coaxial cable, connectors are available in many styles and varieties.  The key difference between them is the frequencies for which they are rated.  The most common connector, known as the UHF style, has been around for many years, having been invented by an Amphenol engineer in the 1930s.  Because its impedance is variable it’s only suitable for frequencies up to about 300 MHz, which includes HF/SSB/Shortwave and VHF.  The most popular designations for UHF connectors are PL-259, the male, and SO-239, the female portion that’s typically located on the equipment and in some cases the antenna.  Anything above 300 MHz, cell, GPS, Wi-Fi etc, requires a more sophisticated type of connector.  These lower loss units include N-Type, BNC, TNC and Mini varieties, all of which are typically available for most cable sizes.  The primary difference between the UHF and these other connectors is those suitable for frequencies above 300 MHz maintain constant impedance, which, at these frequencies, keeps SWR and RF transmission efficiency at an acceptable level.

Termination

At one time the only way to professionally install a coaxial connector for anything other than TV applications was by using solder.  It remains an excellent approach; however, many quality connector manufacturers now offer reliable solder-less coaxial connectors.  In some cases special crimping tools or dies are required while in other cases all that’s required is a needle nose plier.

Properly soldering coaxial terminals requires practice.  These “cold” solder joints are unacceptable, and all holes should be filled.

Proper solder joints, like the one shown here, are critically important.  These can be difficult to achieve if inadequate heat is available when, for instance, the termination is being made outdoors, in breezy conditions.

Whichever approach you use, be certain you understand how the termination is to be made.  A single hair-like strand of a cable’s shield that’s out of place can create a short, which in turn will cause the associated equipment to malfunction.  Most coaxial connector manufacturers include or offer detailed instructions for installation of their products, take the necessary time to familiarize yourself with the procedure, although not terribly difficult it’s often a specific multi-step process.

Great care must be taken when installing coaxial terminals.  A single errant shield strand, making contact with the center conductor, will cause a short and diminish performance. 

When coaxial cables are initially terminated they should be checked for both continuity as well as short circuits.  After installing connectors at each end and before connecting the cable to the antenna and transceiver or receiver, test for continuity between the shield and the core conductor using an ohm meter.

Testing cables using an ohm meter, after terminals are installed, can identify shorts and open circuits before the installation is complete.

The resistance should be infinite, i.e. no connection what so ever between the two.  Any connection, regardless of how high the resistance, is too much, it’s a short circuit that will degrade performance or prevent the gear from operating all together.  Then, using a jumper wire, connect the shield and the core at one end of the cable (make the connection between the center pin and outer body of the connector) and measure the resistance of the connection at the cable’s opposite end.  This will confirm that the connectors are properly installed and are making good, low resistance bonds with the cable.  In this case the reading should be exceptionally low, no more than one or two ohms, most of which is a result of resistance induced by the terminal to cable interface.  High quality coaxial cable alone, without connectors, possesses roughly 1.5 ohms of resistance per 1000 feet.

While it can be done manually, those preparing coaxial cable for terminal installation should utilize readily available special tools. 

Few coaxial connectors are designed to be water proof or even water resistant.  Therefore, installations on weather decks should take this into account and appropriate measures taken to prevent water entry into cables.  Because the shield used on most coaxial cables is made up of a very fine wire braid, it tends to absorb water via capillary action, even when it’s not directly exposed to free water, heavy fog or chronic high humidity will induce water entry into coaxial exposed shield.   Once that happens, the cable’s performance is almost immediately degraded.

A poorly made connection, it lacks water proofing.  Note the visible shield strands, these will act as wicks for water entry into the cable.

Coaxial terminations made on weather decks should be afforded the benefit of dielectric grease applied to the core pin and threaded or bayonet connection before assembly and then sheathing in heat shrink tubing or weather-proof electrical tape (before applying remove all traces of dielectric grease from the outside of the connector and, if using tape, be sure to start the tape wrap low and work upward to the attaching end of the connector, to create a water shedding shingle-effect in the overlapping wraps).  Additionally, if possible, include a drip loop so the cable does not act like a flume, channeling a stream of water toward the connection.

Ideally, this terminal should be completely enclosed in heat shrink tubing.

Because of the importance placed on the type of cable used and because the selection is dependent upon, among other things, the length of the cable run, antennas that are manufactured using en bloc female coaxial terminals rather than pigtail coaxial cables are preferred.  When the antenna manufacturer includes the cable as an integral part of the product the user is often stuck with a cable that may not be long enough, requiring a splice.  Additionally, if the cable is ever cut, crushed or damaged or if it becomes water logged, the entire antenna may have to be discarded.  Additionally, it’s possible that one may wish to utilize a higher quality cable than the one supplied by the antenna manufacturer, especially if a long run is involved.  Additionally, antennas that include a permanent pigtail preclude ohm meter testing of cable assemblies.  Some antenna manufacturers offer the same style of antennas equipped with either a pigtail or a female coaxial connector.  When given the choice, choose the latter so you can use the cable of your choice and so cable assemblies can be tested.

A heavy low loss cable transitions to a smaller diameter “pigtail” cable, one that’s permanently attached to the antenna.  While the bend in the smaller cable is too sharp, the heat shrink tube waterproofing is ideal.

Check This Out

Once all of the connections are made the equipment should be tested.  That means, for radios, radio checks from the greatest possible distance.  Any VHF radio check that’s from a vessel that’s less than 10 miles away is of limited value.  The call should not be placed to the Coast Guard, they have more important things to do and their transmitters and antennas are uber-powerful so it’s likely you’d make contact using little more than a wet mooring line as an antenna.  I once made contact with a Coast Guard communication facility in Portsmouth, VA while half way to Bermuda, roughly 250 miles off shore. Checking VHF operation by tuning in the weather channel also counts for naught when testing a coaxial and antenna installation.

For VHF installations, the only way to be certain the system is performing properly is to obtain a radio check form a distant station, one that is no less than 10 nm. away.

SSB radio checks should be performed both day and night, with successful nighttime radio checks occurring with stations more than 1000 miles distant.  Using an SWR meter on both VHF and SSB installations is an ideal way to check for satisfactory coaxial as well as counterpoise (for SSBs) installation.  Cell phone coaxial and antenna  checks are somewhat more challenging.  You can of course compare the number of available “bars” with and without the external antenna.  Clearly, if the external antenna affords you no additional bars, something is wrong.  Testing coaxial installations for AIS and GPS transceivers/receivers can be somewhat more challenging, however, at the very least the signal to noise ratio function should be accessed and their operation should be carefully scrutinized and compared to other receivers on nearby vessels when possible.  If something doesn’t appear right or if signals are inexplicably marginal or non-existent don’t ignore the problem, find it or seek professional assistance before relying on this gear.

This coaxial cable easily separated from its terminal, likely because it was not properly installed.  The boot shown here, while seemingly desirable, can actually retain water.  Heat shrink tubing or electrical tape is preferred.

Because the loss is difficult to quantify unless it’s actually measured, or the calculations performed, the user often has no idea of just how bad it is.  When I query boat builders or electronics installers about the cable (or antenna) that’s being used in a particular installation, its loss characteristics, length etc. the response is almost invariably, “it’s fine, that’s what we always use” or “no one has ever complained”.  In many cases, smaller diameter cable is chosen because it’s less challenging to run.  And, “fine” is relative, indeed, the VHF radio, GPS or AIS works with higher loss coaxial cable but how well?  After all, if you fail to make contact with your VHF or if an AIS signal from a vessel isn’t received, or if your AIS signal isn’t “seen”, or if you can’t get a GPS lock, will you know it or how often are you thinking that the culprit is the coaxial cable?  Now perhaps you will and you’ll know what to do about it.

From the Masthead

Readers may have noticed that the Marine Systems Excellence eMagazine missed a deadline last week.  That was intentional, however, we also had every intention of alerting readers as to why this occurred, before it occurred.

The fall boat show season is upon us, which includes The International Boatbuilders Exhibition (IBEX), the Fort Lauderdale International Boat Show, and the Marine Equipment Trade Show (METS) held in Amsterdam, all of which I attend.  That, combined with an unusually heavy travel schedule,  has made it challenging for me to produce the detailed and high quality content the eMagazine requires.  Katie, our editor, along with her slew of other normal duties, has been equally busy with arranging my travel, as well as managing the upcoming Cruisers’ Workshop on October 21-22.  With all of that in mind, she and I decided that a fall ‘eMagazine Hiatus’ was in order.    The eMagazine will return in November.

In the meantime, the ‘From the Masthead’ column never sleeps…

Boat Building and ABYC Standards, Again

A couple of weeks ago I attended and lectured at IBEX, in Tampa, Florida.  It’s a place where those in the marine trades (along with a few die gearhead hard boat owners) come together to learn, teach and exhibit, and there’s nothing like it in North America, perhaps the world.  While METS is a stupendous show in its own right, and far larger, it lacks the educational component found at IBEX, and it’s that education aspect that makes it so incredibly valuable.  No true marine industry professional should miss this show.  Among other things, it’s an opportunity for trades people to pose questions in a non-judgmental atmosphere, with and among peers.  The discourse that results is unique and invaluable.  After one session a lecture attendee came up to me and asked the following question, “The boat builder I work for refuses to get onboard with ABYC Standards compliance, he thinks it’s a gimmick and will just drive up costs.  What can I do to change his mind?” .  I expressed my regret, saying he was not the first to share such frustration, and related the following story.

This is an actual case that occurred a couple of years ago.  It’s an all too common occurrence, a client expresses an interest in a vessel, whose specifications I then review.   After the initial review I prepare a set of questions for the builder, which include the following question “Is the vessel built to ABYC Standards and if so which ones?”  In this case, and most like it, the answer is a simple “yes”, which immediately raises concerns on my part because “yes” doesn’t really answer the question, and it implies the vessel meets every Standard, which is rare.  For those that do comply, meeting a series of the most important Standards, roughly 30 out of a possible 60+, is often daunting.  As I delve deeper into the review, which at some point, for a new build at least, includes a look at electrical schematics, it quickly becomes clear that the vessel’s design and systems are not ABYC compliant, at least not where the electrical system is concerned.  There are a series of violations, the most egregious of which involve the lack of fuses or circuit breakers, a potential fire hazard in the event of a short-circuit or overload, and the vessel’s shore power is not equipped with an ELCI, the equivalent of a whole-vessel GFCI receptacle, posing an electrocution hazard.  Other examples included a lack of means of reboarding, i.e. a ladder that can be easily deployed by a person who has fallen overboard, and LP tanks that are stored in a space under the flybridge helm console, along with a range of non-ignition protected electrical and electronic gear; representing an explosion hazard.  After pointing out these and a variety of other issues, the builder sheepishly responds by saying, essentially, he is an ABYC member, he knows they have a copy of the Standards, somewhere, and he thought they were compliant.

Let me be clear, where diesel-powered recreational vessels are concerned, ABYC Standards are purely voluntary, there’s no legal mandate to meet them, and this is often the retort  from boat builders when such violations are identified.  While strictly speaking that is true, any boat builder (foreign or domestic) that sells vessels in the United States, and does so knowing that they do not comply with at least the most important safety and reliability-related standards, electrical, fuel, LP gas, reboarding, exhaust system, to name a few, does so at their own peril.  When, for instance, I point out, as noted above, that a fuse is missing form a location where it’s required for ABYC compliance, and the builder balks, often saying, “We’ve been building boats for XX years and we’ve never installed a fuse there, and it’s never been a problem, why should we start now?” I usually respond by saying, in addition to the technical reasons for its inclusion, “Imagine yourself sitting on a witness stand, explaining to a jury why you didn’t install this fuse, which would have cost less than $50, after a vessel you built caught fire, and burned, injuring or killing some of those aboard. Because you are under oath you’d also have to say ‘yes’ when asked if you’ve heard of ABYC Standards, and if you were aware they called for the installation of this fuse, and that in spite of this readily available information you knowingly disregarded it, choosing instead to, and an attorney will emphasize this, save $50.  Do you want to find yourself in that position, and is it worth it?”

I’m not one to play the legal scare card, and I’d much rather boat builders and those in the marine repair industry follow these Standards because they make for safer and more reliable boats, but the litigious aspect cannot and should not be ignored.  If you are in the industry, think carefully about this and how you would deal with such a question, both legally and morally.  If you are a boat owner, or buyer, be sure to ask about compliance with ABYC Standards when considering a new vessel or when preparing to have work carried out on the one you own.

Text and photos by Steve D’Antonio

Copyright © 2017

From the Masthead

About a year ago a client of mine, I’ll call him Frank, had text exchange with a marine industry contractor, let’s call him Bill.  Frank asked Bill to carry out some routine work on his boat, work Bill has undertaken for Frank on other occasions in the not too distant past.  The price Bill quoted, however, was twice what it had been previously.  Granted, Frank now had a new boat, but the work was essentially the same, the same brand of equipment and a similar age.  Frank was a bit taken aback and asked Bill if he’d reconsider.  The way Frank phrased his request came out sounding as if he was bargaining or asking for a discount; he wasn’t.  Bill’s responses were short to begin with and they became even shorter at this point; after a couple of exchanges Bill essentially said, “Thanks, you’ll need to find someone else”.  Bill essentially fired Frank, an otherwise loyal customer.

Bill is good at what he does and is in demand, and I’m sure he thought, ‘I don’t need this’.  Still, with each text message I cringed, both parties were heading toward the inevitable unhappy ending, and I watched it, the proverbial slow motion train wreck.  Ultimately Frank hired someone else, who performed the work competently and effectively, so it’s unlikely he’ll ever call Bill again, and truth be told Bill probably doesn’t care.  But is this the best course of events for both parties?  No, absolutely not, it’s bad all around, Frank is unlikely to ever refer anyone to Bill and he’ll probably tell this story again and again.  Bill is busy now because the economy is on the rebound, but as all of us old marine industry hands know, that can and will change.  Good will is money in the bank, and it should be saved rather than squandered.

I’ve thought about this episode a great deal since it happened.  The sequence and outcome could have been avoided entirely, and here’s how.

• When working with a marine industry contractor avoid using the word “discount”, it’s off-putting to marine industry professionals and rightfully so, why should they discount their efforts and hard-won experience? If the price is more than you can afford, or are willing to pay, you have a few options.  You can shop around for the same quality work at a lower price, or you can say, “That’s more than I’ve budgeted for this project, is there any way to do it less expensively?”  That leaves open the option for using different materials, or taking another less invasive, and perhaps less thorough, approach.  If the contractor is the only person who does what he or she does well, in the region, and he or she is busy, be prepared for a “No”.  There’s no harm in asking, provided it’s done professionally and respectfully.
• If you are a marine industry professional, and you are good at what you do, and you are in demand, you must resist the temptation every day to become over-confident, cocky or worse, develop a reputation for being a prima donna.  That doesn’t mean you are obligated to negotiate or defend your fees if you don’t wish to, it simply means you say ‘no’ in a professional, polite manner, leaving the door open for the customer to agree to use your services on your terms.  When asked to discount your fee, if you don’t wish to, simply say, “I’m sorry the fee is not negotiable, but I’m convinced the value you’ll get for that fee is undeniable, it includes xx years of experience, x professional certifications and $xxx,xxx worth of tools and equipment to do the job properly, and I stand behind my work.  I’m certain you’ll be satisfied and I’m also happy to provide references”, delivered sincerely and without an attitude.  That response, which should take no more than 30 seconds to deliver, will make it clear the fee is the fee, and it does so without animosity or hard-feelings.
• Finally, the Frank and Bill exchange should have quickly progressed to a phone call.  As I’ve said countless times in customer service and communication seminars and workshops, it is very difficult to convey intent, sentiment and tone in an e mail or worse, a text.  In Frank’s case, after he received the quote, which was double the previous fee, he should have called Bill and said, “Bill, maybe I misunderstood, but the fee is much higher than the last time you did this work for me, what’s changed?”  The likelihood of a dispute being settled amicably is far greater when it occurs  in a live conversation rather than electronically.

This month’s eMagazine feature article covers the all too important subject of electrocution prevention.  I hope you find it both interesting and useful.

Electric Shock Drowning and ELCIs Explained

An equipment leakage circuit interrupter or ELCI, is capable of sensing faults in a vessel’s AC electrical system, whereupon it will turn off power in the blink of an eye, ideally before an injury or fire can occur.  With few exceptions, ABYC and CE-compliant vessels must be equipped with this component.

In 2012 three cases of electrocution or electric shock drowning (more on that below) occurred over the Independence Day holiday.  Tragically, they resulted in the deaths of four children, siblings Brayden and Alexandra Anderson 8 and 13 respectively, Noah Winstead, 10, and Nathan Lynam 11, and one adult, 26-year-old Jennifer Lankford.  All of the events occurred on lakes, one in Tennessee and the two in Missouri.  More recently, on April 20, 2017 three more cases occurred, in which 15-year old Carmen Johnson, 34-year-old Shelly Darling and 41-year-old Elizabeth Whipple were all killed while swimming in Alabama’s Lake Tuscaloosa.  In June of this year five more people were killed at a water park in Turkey, again by electrocution or electric shock drowning.

The most reliable way of preventing electric shock drowning is to avoid swimming around docks with shore power.

Each year electrocution, in most cases more accurately referred to as electric shock drowning or ESD, more on that in a moment, events such as these occur and each year a hue and cry goes out within the marine industry to educate boat owners, marina managers, marine electricians and swimmers about the dangers associated with swimming around boats that are plugged into shore power, or other shore power devices such as electric boat lifts.  Sadly, for these people, most of whom are children, and their families, it’s too late; however, it’s not too late for you to learn about these potentially disastrous scenarios and how to avoid them.

ELCI’s

You would be hard pressed to find an adult who is unfamiliar with the ubiquitous Ground Fault Interrupter or GFI receptacle.  Found in household kitchens, bathrooms, patios and garages among other locations, and recommend by the American Boat and Yacht Council for use in heads, galleys, engineering spaces and on the weather decks of boats, they have no doubt saved countless lives since their introduction in the late 1960s.  Requirements for GFI’s have been part of the National Electric Code for over 50 years, with the first mandate being inspired by electrocutions caused by underwater lighting used in swimming pools.

In a properly functioning marine electrical system, the same amount of AC current flows in the hot and neutral wires.

However, if electricity “leaks” from this intended path in these two wires to ground, this condition is called a ground fault. A good example of this is an insulation failure in the wiring of an appliance.

In addition, a faulty ground can occur when the grounding path is broken through a loose connection or broken wire. For instance, a shore power cord ground wire may fail due to constant motion and stress.

Wiring diagrams and associated captions courtesy Blue Sea Systems.

While GFI’s have been covered in a previous column, there is yet another shore power safety device, one that was only introduced to the marine market within the last decade, that’s also worthy of attention.  Referred to as an Equipment Leakage Circuit Interrupter or ELCI (sometimes referred to as RCD’s or Residual Current Devices), it offers yet another level of protection from shore power faults, fire and electrocution or ESD.  Much like a common GFI receptacle (these have a comparatively low trip threshold of 5 milliamps, and as such are considered to be appropriate for protecting people, they represent local protection), ELCI’s remain in a state of equilibrium, allowing energy to flow, as long as the current on the hot and neutral wires, the two current carrying conductors found in most AC electrical circuits, remains the same.  As soon as current finds an alternative path back to its source (contrary to popular belief, electricity does not seek ground, it seeks to return to its origin, in this example likely the transformer at the head of the dock), through a green safety ground wire, the water or a human, the imbalance trips the ELCI’s circuit breaker and the power is turned off nearly instantly, often within 30-70 milliseconds.

Like GFI’s, ELCI’s (sometimes referred to as RCDs) must include a test feature, the blue button with embossed T.

While technically deemed “equipment protection”, because of their 30 milliamps trip threshold, the goal of ELCI’s is to interrupt current flow quickly enough to prevent electrocution, electric shock drowning or fire, and for the most part they do so very effectively, saving, much like GFIs, countless lives every year.

The adoption of the ABYC ELCI Standard was, much like the GFI, inspired by a number of electric shock drownings or ESD’s.  Different than a conventional electrocution, an ESD can, with comparatively little current flow, paralyze a swimmer’s voluntary muscle reflexes, causing him or her to drown, which only serves to mask the underlying electrically-related cause of death.  For more on ESD and how it occurs and differes from conventional electrocution, see this Marine Systems Excellence article.

“Electrocution” is a broad term, and the range of current has many differing effects.  Those that may be non-life threatening ashore, such as muscles freezing, can lead to drowning while swimming.

While it’s true that virtually all documented ESD cases have occurred in fresh water, the risk of swimming around docks and boats that are energized with shore power, in salt or fresh water, remains extremely high.  Some will say, “It can’t happen in salt water”, and I cringe each and every time I hear this.  There are several reasons this “theory” represents dangerous folly.  One, it’s impossible to determine the salinity level of a body of water before jumping in to cool off.  In estuarial waters like the ones where I live, on the Chesapeake Bay, salinity changes seasonally and even daily after heavy rains.  Two, it’s impossible to rule out the potential for ESD or electrocution in seawater provided the current flow is high enough.  Do you want to risk your life or the lives of your loved ones by testing this belief?  Some have also said that if an ELCI, leakage warning system or transformer is used, it’s then safe to swim in the vicinity of energized docks and boats.  Again, this is incorrect; it’s dangerous and risky at best.

Ground fault interrupter receptacles have been around since the 60’s.  Having saved countless lives in that time, they should be installed in a vessel’s head, galley, on weather decks and in engine rooms and machinery spaces.  They provide local protection and are still required even for vessels equipped with an ELCI.

In addition to the trip threshold, the primary difference between the ELCI and its cousin the GFI, is the location in which it is installed.  GFI receptacles are installed where power is to be used, galley, head etc, while ELCI’s are installed where power enters the vessel, near the shore power receptacle.  Think of it as a whole boat GFI with some modifications.  A primary shore power circuit breaker is already required for every shore power inlet, and in the case of an ELCI it is often installed either in conjunction with this breaker, or as a single combined unit, achieving the goals of over current protection and fault protection.  It’s important to note that the presence of an ELCI does not negate the need for individual GFIs, both are still required for ABYC compliance.

ELCI’s, the blue-handles, are often combined or co-located with primary shore power inlet circuit breakers, the black two pole devices to the right of the ELCI.   Don’t assume an ELCI trip current is correct, as they are available in a wide range, from 5 mA through 100 mA.  ABYC compliant ELCI’s should be designed to trip at 30 mA, those seen here indicate this in the “I=0,03A” shown on their face. 

ELCI’s got off to a rocky start when they were first introduced to the ABYC Standards and the marine industry in 2008.  As is often the case, the intent preceded the hardware, and as a  result the implementation was postponed for a couple of years.  Now, however, proprietary marine ELCI circuit breakers are readily available from several manufacturers in a range of configurations. With few exceptions, new vessels that are built, or those that are being refit, to ABYC (or European CE) Standards must be equipped with ELCIs, and with good reason; they save lives.  An ELCI can be added to virtually any vessel’s shore power system provided it is free of faults.

If the wire-run distance between the shore inlet and the circuit breaker panel is less than 10 feet, the ELCI may be located in the latter.

Folks often ask me when it’s OK to swim around docks, saying, ‘What if the vessel does have an ELCI?” or “The dock has a leakage warning system, is it OK then?”, or, “Can the water be tested before swimming?”. Unfortunately, the answer is no to all of these scenarios for a variety of reasons, including and especially because faults occur in a split second, one minute the water is safe, the next it’s deadly, and unless you can walk on water you can’t count on being able to get out of harm’s way quickly enough.   Also, as wonderful as ELCI’s and GFCI’s are, they are not foolproof.

You might ask, “What about divers?  I see them in the water in marinas all the time and they don’t get electrocuted”.  Whenever I encounter one on a dock, and that’s often, I make it a point of asking, “Do you ever get shocked or feel a tingle?”  Without exception every one has said yes, several have told me they can feel electricity coursing through their dental fillings.  A dry, and even wet, suit does offer some protection against electrocution and ESD, which is why these folks probably haven’t become victims.   They do this work at their own risk, hopefully knowing the hazards (one was killed recently in Florida, albeit by a bow thruster rather than ESD), a far different scenario from your child frolicking in the water on a seemingly care-free summer day.

Simply put, never swim around docks equipped with shore power in fresh or salt water. There are no exceptions to this rule.

Next month I’ll discuss shore power transformers and the role they play in electrocution prevention, and fault avoidance.

Text and photos by Steve D’Antonio

Copyright © 2017

From the Masthead

Apprenticeships Revisited

Readers of this column know that I’m passionate about marine industry professionalism and expertise, an integral part of which involves vocational training and apprenticeship programs.  I’ve written about these programs in other countries, notably Australia, and have lamented the dearth of such options within the American marine industry (as well as other technical trades).  According to the labor department, nine out of 10 Americans who complete apprentice training find a job with a starting salary of $60,000 a year.  An article in a recent issue of ‘Soundings Trade Only’, a marine industry journal, details the latest efforts by the Trump Administration to expand and enhance vocational and apprenticeship opportunities in this country.  I welcome and applaud this effort, which sends a clear message, not only is college not for everyone, there is a clear need, and respect, for those with a technical rather than academic education, and the need for skilled, well-trained and experienced professionals within this industry has never been greater.  Boat builders, dealerships and boat yards have been clamoring for skilled staff since the recession ended, and they report the employment gap grows with each passing month.  When I managed a Virginia-based boat yard, my greatest challenge involved the pursuit of skilled professionals; ultimately forcing us to recruit nationwide.  That was ten or more years ago.  With each passing year propulsion and onboard mechanical and electrical systems become increasingly complex, driving up demand for those who have the skills to install, maintain, troubleshoot and repair them.  I will continue to watch, write about, promote and report on this trend.

Nikita cruises before a waterfall, in what is acknowledged as one of Norway’s most picturesque regions, Geirangerfjord. 

Cruising Technology

I recently completed an 18-day passage aboard a Fleming 75 in Norway.  The vessel proved as interesting to me as the breathtaking Scandinavian scenery.  A 2004 model, Nikita recently underwent a lengthy refit, during which, among other things, she received a new navigation and communication suite, a Maretron monitoring system, and lithium ion battery bank.  The latter was of particular interest to me.  Thanks to, among other attributes, their light weight, dense capacity footprint, and rapid recharge time, lithium ion batteries, now common place in automobiles, hold great promise for marine cruising vessel house battery banks.  In the last couple of years, and thanks to early adopters, they have progressed from bleeding to cutting edge technology.  Spending time aboard this vessel allowed me to carefully evaluate both the installation and performance of this system.  While there remain a series of caveats for their use, I’m pleased to report that the results from this vessel were very encouraging.   I’ll cover the details in an upcoming article.

This month’s eMagazine feature article covers the subject of advanced battery charging and alternator regulators.  I hope you find it both interesting and useful.

Alternator Regulation

Without properly designed and installed advanced regulation, high output alternators will be unable to effectively, safely and rapidly charge large house battery banks.

A few years ago I inspected a new, and finely-crafted 57 foot single screw cruising vessel, whose 12 volt (by all rights the vessel should have been 24 volt, but that’s another story) house battery bank possessed over 1000 amp hours of capacity (an amp hour is the typical unit of measure for deep cycle batteries and large battery banks, one amp hour represents the usage of one ampere for one hour, while ten amperes of usage for four hours equals forty amp hours and so on).  Just a few years ago this would have been considered a huge battery bank, however, by today’s onboard electrical standards it’s moderately-sized for a serious cruising vessel.

The owners’ complaint was a refrain I’ve been hearing for most of my nearly three decade-long professional career; “The battery bank isn’t big enough”.  Although I suspected I knew why this cruising couple was saying this, I inquired as to why they believed this to be so.  The response, “the batteries aren’t lasting long enough between charging cycles, in the morning the batteries are nearly dead”, confirmed my suspicion.  Indeed, the battery bank required all too frequent re-charging, but not because it was undersized (if anything it was over-sized when compared to the charge capacity).  The problems lie in the method(s) of charging.

The vessel was equipped with a stock alternator supplied by the engine manufacturer, with a 100 amp capacity.  While this may seem like a lot at face value, it’s woefully undersized for the task.  Furthermore, because the alternator was internally regulated, as nearly every stock unit is, it was incapable of recharging a large house battery bank with any degree of efficiency.

Alternators, Not all are Created Equal

It’s important to note that most marine engines are industrial blocks that are marinized; they are destined for trucks and other industrial applications where the primary requirement of their alternator is to recharge a starting battery whose amp-hour capacity is often something less than 100 amp hours.  Most marine engine manufacturers follow a similar regimen, the alternator is designed to charge the engine’s own starting battery, as well as supplying power for pre and post heat systems (this is why more and more diesel engines are equipped with seemingly large alternators, as the heating elements are exceptionally power hungry, albeit for a short duration), instrumentation, electronic engine control if so equipped etc.  The average engine start cycle requires less than one amp hour, thus replacing it requires very little effort or time on the part of a stock alternator.

Insidiously, some stock alternators are deceiving in that their output is seemingly high, as in the case of the aforementioned cruiser, offering a hundred or a hundred and fifty amps.  The problem with these alternators is two-fold.  First, they are internally regulated and therefore not equipped to deliver the multi-stage charge required by deep cycle house batteries.  Second, with few exceptions they are not designed to deliver their full output except for short periods of time.  When called upon to do so, by retrofitting one of these alternators with an external regulator as is sometimes done, they often expire prematurely as a result of overheating.

Because they are unable to dissipate heat, most stock alternators supplied with engines are not designed to be externally regulated, regardless of output rating.  A healthy stock alternator’s lacquered copper windings (above) remain bright and shiny, while the windings of an over-heated stock alternator (top), one that was externally regulated, show clear signs of heat stress, wherein the lacquer coating has been vaporized.

The difference between a near-continuous duty high output alternator and a high output stock alternator is, to paraphrase Mark Twain, like the difference between lightning and a lightning bug.  The trouble, however, doesn’t end here.  Not only is the stock alternator not equal to the task it’s being called upon to carry out, even when externally regulated, its output, contrary to initial perceptions, is simply inadequate.  While 100 amps may appear substantial, it’s anything but when compared to the massive bulk of many of today’s house battery banks.  In the case of the 57-foot cruiser, it’s a mere 10% and even if it was a proprietary, continuous duty high output alternator it still would be inadequate.

A handful of stock, off the shelf high output alternators are capable of being externally regulated.  This Leece Neville/Prestolite model is one example, it produces 175 amps at 24 volts.

Depending upon the battery type, flooded, gel or AGM, the rule of thumb for the ratio of charge output to battery bank size calls for the charge source, an alternator(s) in this case, to be a minimum of 25% of the bank’s amp hour capacity (gel batteries can initially accept 50% of their amp-hour capacity, while AGMs can accept 100% and in some cases more, flooded batteries are limited to 25%, hence the 25% rule of thumb).  That is, the alternator output required for this battery bank, in order to achieve reasonable re-charge times, should be at least 250 amps.  Continuous duty alternators of this capacity are available, however, they are not inexpensive and their installation requires careful engineering and often fabrication of heavy duty brackets.  Custom pulleys may also be required to fine tune the alternator’s speed (alternators have a sweet spot, where they generate maximum current while providing adequate cooling from their built in fans; all alternators have a “red line”, a maximum allowable rpm which must not be exceeded) to achieve maximum output at the vessel’s cruising speed.

Not all high output alternators are designed to supply current for an extended duration, to do so they must be able to effectively dissipate internally-generated heat.  Those that are not designed for the task are destined for an early grave.

In some cases, two alternators (either on a single engine or one each on a twin screw application) may be required to achieve the required output.  When dual alternators are used simultaneously, both outputs should be connected directly to the house battery bank, and they must be synchronized so they behave as a single alternator.

After my inspection of the 57-foot cruiser I recommended that the stock alternator be replaced by a continuous duty 200 amp unit (the largest that could be accommodated by this engine’s mounting design without significant modifications) along with a multi-stage, temperature-compensated regulator and a battery bank amp-hour monitor, which would enable the owner to accurately determine how many amp-hours had been used by the bank, which in turn would dictate their re-charge cycle.  Additionally, when at anchor the only charge source was an inverter charger whose charge capacity was 110 amps.  Again, while that may sound like a lot, it’s simply not enough for recharging 50% (common wisdom holds that conventional batteries, flooded, AGM and gel, should not be discharged more than 50%, doing so will diminish the total number of amp-hours derived from the bank over its life) of this bank’s capacity, at least not in a reasonable time period.  This was augmented with two additional 100 amp chargers, for a total of 310 amps during the bulk charge phase.  Because the bank was made up of AGM batteries, in theory it could have supported three times this amount of charge capacity.

The vast majority of batteries, particularly sealed valve regulated versions, AGMs and gels, suffer an early death thanks to improper charging regimens.

With this gear in place, as well as a little training regarding battery bank monitoring and discharge protocols, the perceived need for a larger battery bank evaporated.

Although the error was no doubt unintentional, the builder of this vessel never should have installed a mega-battery bank knowing it would be serviced by a mini-charge source.  Battery banks, particularly large ones, must always be treated as an integrated package whose design is based on the electrical needs of the vessel/crew, the desired quiet ship time, and the charge source.  Failure to treat each leg of this battery triangle equally nearly always results in a system that fails to live up to expectations.

Alternator Regulators

While the integration of this system is vitally important to its efficient operation, there are a variety of details and ancillary items that must also be considered.  Among the most important are the methods by which the alternator or alternators are regulated.

As mentioned above, all alternators are not created equal.  Most are designed for short duration high output scenarios, to recharge a start battery or perhaps to supply power to an air intake post heating system for the purposes of reducing smoke upon start up.  The solution is to utilize an alternator that’s designed for extended high output operation.  That, however, is only half of the high output charging equation.  Alternators of this variety are long on brawn and short on brains.  While exceptionally robust and capable of delivering amps galore, they typically lack regulation of their own and proper regulation is especially important when it comes to recharging a large battery bank as quickly and as safely as possible.

Smart, three stage, temperature-compensated regulators are the heart of a high output charging system and large battery bank.  Without them, most stock alternators tend to under or over-charge the banks they serve. 

The internal regulator supplied with most stock alternators has a reliable but unsophisticated charge profile or voltage range.  In spite of the alternator’s rated output, when guided by such a regulator, it’s simply not capable of replacing large amounts of energy that have been drawn from a heavily depleted house battery bank, or doing so in a manner that ensures the longest possible battery life.  When called upon to do so, after an initial high output, it often tapers back to a modest charge rate.  The results are twofold.  One, the battery bank becomes chronically undercharged and two, the voltage that the batteries are exposed to is often incorrect, which leads to poor performance and a shortened lifespan.

Fortunately, the solution to the problem is straightforward enough.  In addition to correctly sizing a proprietary high output alternator for the battery bank that is or will be installed, it must be controlled by an external multi-stage “smart” regulator.  Smart external regulators have been available to the marine industry for many years, I installed my first 25 years ago, and even the earliest models represented a vast improvement over what were hitherto available, internal regulators, the vast majority of which weren’t even adjustable.  External regulators pair precision control with a high output alternator’s brute force, offering the user the best of both worlds.

The owner of the most advanced high output charging system is flying blind unless he or she is able to monitor the battery bank’s state of charge, using an amp-hour meter like the one shown here.  Amp-hour meters are every bit as critical to these systems as multi-stage regulation.

The key to effective management of alternator output is to supply it in distinct stages, bulk, which is typically between 14.1 and 14.6 volts, 28.2 and 29.2 for 24 volt systems, acceptance or absorption, usually 2/10 of a volt below bulk, and float, which is typically one volt below bulk.  Each battery type has its own ideal charge profile, for which most smart regulators can be programmed.

Batteries are able to accept different charge rates as a function of their internal resistance, which in turn is a function of their state of charge or SOC.  Heavily discharged batteries have low resistance, and can therefore accept higher current, while nearly fully charged batteries possess high resistance, and therefore accept current more slowly.  This is why replacing the final 10%-15% of a battery’s charge can be a very slow process; internal resistance is high, thereby limiting the charge acceptance rate.

When compared to their conventional brethren, smart regulators are much better able to determine, and take advantage of, these states of charge, tailoring the alternator’s output for the greatest charge efficiency, and thereby ensuring the shortest possible recharge time.

Bulk is, as the name implies, the highest output stage of the alternator/regulator.  It sends a heavily depleted battery bank the greatest possible amperage that it can safely accept (send too much and it will cause the battery to overheat and possibly catch fire).  As the bank’s state of charge increases, the regulator switches to acceptance mode, which is essentially a throttled back charge rate, held at a constant voltage.  Finally, once the battery is fully charged the regulator enters a float mode, keeping the battery bank’s voltage high enough to prevent self-discharge and sulfation (an accumulation of energy-robbing sulfate crystals on the batteries’ plates) and low enough to prevent overcharging.

I don’t believe it would be an overstatement to suggest that multi-step charging protocols have been to large house battery banks what fiberglass resin has been to boat building.  Without this approach, using large battery banks and recharging them in a reasonable amount of time would be virtually impossible.  Absent this level of charge efficiency, convenience and functionality the plethora of DC gear that’s become an integral part of the modern cruising vessel would be impractical.

Temperature-compensation plays a critical role in high output charging systems; it should be considered a prerequisite in any high output alternator or shore charger installation.

Although deemed optional by some, temperature compensation is, in my opinion, an indispensable part of any multi-step smart regulator system.  Because batteries are capable of accepting a higher voltage when cold and consequently incapable of safely accepting the same voltage when hot, temperature compensation plays a vital role in establishing battery charging parameters and increasing longevity.   Simply put, temperature compensation is a must for any multi-stage charging system, whether derived from an alternator or shore-powered charger-inverter/charger.

Shore or generator-powered chargers play an equally important role in properly charging large battery banks when the vessel is not underway.  Inadequately-sized systems lead to extended generator run time, with the nuisance, additional maintenance and maladies that accompany it.

I recently inspected a battery bank that was (wisely) located in the lazarette as the vessel cruised the Bellingham Channel, where the water temperature was a chilly 53°F.  The charge rate was noticeably higher than, say a vessel I inspected the previous month, it was located in the Bahamas, the water temperature was 75°F, and its batteries were stationed in the engine room.  The temperature compensation probe enables batteries living in vastly different environments such as these to be charged safely, efficiently and quickly (or as quickly as possible) while ensuring maximum battery longevity.

Typically, the probe is adhered to the battery case, or bolted to one of the battery terminals in the house bank (the stick-on probes are notorious for falling off, I usually apply a bead of silicone sealant over them to keep them in place.  It’s important that the probe be installed on the house rather than the start bank, as the house bank will be heavily discharged and cycling and it’s the bank to which the alternators’ output should be directly connected.  If the house bank is split between two locations, which is undesirable, the temperature probe should be installed in the location that is anticipated to be hottest, the engine room rather than the lazarette for instance.

Temperature compensation doesn’t stop at the batteries, alternators also benefit from this feature.  This temperature probe  will alert the regulator to an impending overheat scenario, at which point the regulator will reduce the load placed on the alternator.

For vessels equipped with twin propulsion engines, the preferred approach, for maximum charge capacity, calls for the installation of one high output alternator on each engine with, once again, both outputs connected to the house battery bank.  In order to operate properly, however, they must be synchronized using a device that will enable them to act in concert rather than in opposition.  If separate, unsynchronized regulators are used, one of a twin independent alternator set up will often prevail, leaving the other in idle mode, essentially nullifying the value of a twin arrangement.

Some regulators are capable of simultaneously controlling the output of two alternators.  Taking this approach ensures the alternators will always work in concert.  An intervening device may be, but is not always, required, check with the manufacturer of your regulator.  Provisions must be made to disable the field voltage to an engine/alternator that is not running, this may be done automatically, using the aforementioned synchronizing device, or via a manual, or oil pressure actuated, switch.  By the same token, twin high output alternators installed on the same engine also benefit from being controlled by a single regulator.

Depending upon their sophistication, and cost, regulators may encompass additional valuable features.  These include start delay, which gives the engine and belts time to warm up before applying alternator load, as well as preventing the alternator from placing a load on a smaller engine during cranking.  A remote battery sense enables the regulator to measure and compensate for the battery bank’s actual voltage, thereby taking into account voltage drop between the battery bank and alternator.  The value of battery temperature sensing has already been mentioned, however, the same approach can be used for the alternator itself.  By sensing its case temperature, the regulator can reduce the load on the alternator if it becomes too hot.  Finally, a belt management program enables the user to intentionally de-rate an alternator’s output, thereby reducing the load on the alternator and engine crankshaft pulley.  This can be especially useful in small engine applications, where crankshaft as well as belt loads must be managed, or where, for longevity purposes, over-sized alternators are used, a 400 amp alternator for instance, being limited to 250 amps will run cooler and last longer than a 250 amp alternator running without limitation.

All alternators are designed to produce maximum output within a specified rpm.  Ideally, the alternator will reach this sweet spot at the vessel’s cruising speed.  Too much of a good thing can be problematic, however, as over-speeding an alternator will result in its self-destruction, pulley seizure, and engine stoppage.  Make certain you, or your electrician, do the pulley math before proceeding with a high output alternator installation.  This installer failed to ‘do the math’, causing the alternator to overheat and seize.

Advanced alternator regulation is now well-understood, there’s no reason not to take advantage of it; where large battery banks are concerned, regardless of whether they are flooded, gel or AGM, it’s a veritable prerequisite.

Text and photos by Steve D’Antonio

Copyright © 2016

From the Masthead

Have you tasted the tea lately? 

About two years, in order to make time zone transition easier, I gave up drinking  coffee.  I frequently traverse multiple time zones, my record is 27 in ten days,  making it challenging to get restful sleep.  Sleep experts have noted that caffeine hinders time zone acclimation, and since forgoing it I’m forced to agree.  Additionally, it’s tough to get coffee in some places, particularly in China.  My morning ritual involved drinking a cup while reviewing e mail.  When in Asia I began to find myself fretting the night before about where I would get my cup of joe, and more worrying was the acquisition of milk, which is even more scarce than coffee in China.  Thus, I’ve taken to drinking decaffeinated tea (I was a tea drinker until getting married, at which point my wife indoctrinated me into the coffee drinkers’ cult), which is easy to carry, and I drink it neat.

In making the change I’ve made an interesting discovery, much of the hot water offered for tea, particularly in the US, has a distinctive stale coffee taste.  It simply ruins the tea flavor and is virtually undrinkable.  The reason of course is the hot water is dispensed from urns that once contained coffee, thereby tainting the taste of whatever they hold thereafter.    What I wonder, however, is how those serving it, in hotels, in flight, at airport lounges and elsewhere, could be unaware of this glaring tea faux pas, unless of course they never taste it themselves, which brings me to the marine industry analogy.  When I review invoices prepared by the marine industry, particularly boat yards, I often find myself wondering how they could not know that what they are producing is virtually unintelligible. I also can’t help but wonder if those preparing this material read and critique not only the content but the format as well, which, once again, is often the epitome of illogical and convoluted.  To be fair, having worked on boat yard invoice formatting, it’s impossible to please every customer, however, it is possible to clarify and simplify invoices to make them more understandable to the layman.   The problem of course is those creating these invoices can’t see the forest for the trees, being so close to it, and knowing subject matter so well, often makes it difficult to recognize the flaws, and of course there’s the natural unwillingness to admit fault if they are responsible for the format’s design.

If you agree, then the next time you receive such an invoice I strongly suggest you share it with the proprietor of the organization responsible for it, let him or her know what you don’t like about it and why, and say, “Imagine if you received an invoice like this from someone you’d hired to undertake a task about which you knew little, roofing or furnace repair for instance, what would your reaction be?”.  Figuratively speaking, suggest they take a sip of their own tea.

This month’s Marine Systems Excellence column covers the subject of engine drive belts, I hope you find it both useful and interesting.

Belts

Notched belts are well suited to small diameter pulleys.  Using them reduces the likelihood of belt overheating, which is caused by rapid flexing of conventional belts.

The belts that drive an engine’s accessories, which include the raw water pump, circulator pump, and alternator, as well as perhaps a refrigeration compressor and even a hydraulic pump, will typically offer reliable trouble-free service, provided the system is properly designed, and components are maintained, adjusted and replaced before they reach the end of their service life.

While nearly all belts are installed either by adjusting a driven pulley’s position, an alternator or pump for instance, or by compressing a self-tensioning device, some like the one shown here (upper right) rely on “rolling”, where the belt is simply stretched over a pulley by rotating the latter.

Many vessel operators neglect this all too important component, however, waiting until disaster strikes.  Once a belt breaks, all of these vital systems grind to a halt, literally.  The raw water pump stops pumping seawater, the circulator pumps stops circulating coolant and the alternator no longer produces electricity.  For engines that use multiple belts, the failure of one usually spells the demise of the others, as the flailing deceased belt often entangles with, and takes down, the others in the process.  While you may not immediately notice the loss of an alternator, you will very quickly become aware of the loss of seawater and coolant circulation as the temperature gauge climbs into the red, and the overheat alarm sounds (have you confirmed that your coolant high temperature annunciator works, it should sound or chirp each time the key switch is turned on, and you have a wet exhaust high temperature alarm as well, right?).

A properly selected and tensioned belt typically runs at roughly the same temperature as the engine’s coolant,  between 175°F and 200°F.

Belt Types

The belts used to power these accessories are either the V variety, or the ribbon-shaped flat serpentine style.  While V belts were the standard for decades, I clearly recall, as a young mechanic, the day when marine engine manufacturers first began emulating the automobile industry by adopting serpentine belts, it was truly exciting in a gearhead sort of way.  From a mechanic’s and do it yourselfer’s perspective, serpentine belts are very attractive in that they are more robust and reliable, one belt is typically all that’s needed, they are far easier to replace; and most are self-tensioning.

While most serpentine belt-equipped engines rely on an automatic tensioning device, some smaller models continue to utilize the alternator’s adjustment for tensioning purposes.

V belts, on the other hand, have their idiosyncrasies, often, multiple belts are needed, one may do double duty, sending power from the crankshaft pulley to both the alternator and circulator pump, while another belt may be used to turn a raw water pump.  Generally speaking, unless a serpentine belt is used, conservative installations will resort to double V belts (for the most part matched belt sets are no longer used, as the manufacturing tolerances of higher quality belt manufacturers makes this unnecessary), when amperage exceeds 100 amps at 12 volts, or 50 amps at 24 volts.

A Gates “Krikit” belt tension gauge, which enables users to apply proper tension to V belts.

Belt Service

Ordinary V belts are, with a little special knowledge, easily serviced, adjusted and replaced.   “How tight should my belts be?” is almost certainly the most commonly asked question for those carrying out service and replacement.   One dockside rule thumb calls for one half inch of belt deflection for every foot of belt span between pulleys, sometimes referred to as sheaves (rhymes with cheese).  The problem with that approach is the deflection varies with the force that’s applied, and with no means of measuring that force the formula is of little use.  Fortunately, a tool does exist for this application.  Called the Kriket™, and made by Gates Rubber, it takes the guess work out of tensioning V belts.  It’s readily available on line and at many auto parts stores, and is useful for both professionals and boat owners alike (I find pro’s tend to overtighten, while boat owners under tighten belts).

Belt dust, which is frequently generated by misaligned belts, is extremely fine.  In addition to distributing itself over the front of the engine, it’s also drawn into the alternator, where it is deposited, and interferes with heat dissipation, as well as the engine’s air intake.

An under-tensioned belt will slip, and a slipping belt won’t turn its related accessories properly, it will overheat, wear out and break prematurely.  An over-tensioned belt will accelerate wear on driven accessories’ bearings and seals.  In addition to tension, alignment is another issue that must be dealt with.  An accumulation of belt dust on the front of the engine or the alternator casing and fan, it’s often so fine and “greasy” that it’s mistaken for an oil leak, is nearly always an indication of a misaligned belt.  Because it is so fine such dust is nearly always drawn into alternator windings, to which it adheres and hinders heat dissipation.  Misalignment is a common occurrence in the case of after-market high output alternators, where support brackets are either improperly designed, or where they lack the necessary rigidity to prevent flexing and distortion when belts are tensioned.

Belt engagement is critical, particularly on highly loaded components such as high output alternators.  The rule of thumb for these is no less than 120°.

Shedding of belt chips, or chunks can be a sign of a heavily loaded belt that lacks sufficient pulley engagement or tension, which can cause the belt to skip; this is also especially common on high output alternator installations, where belts should engage pulleys for a minimum of 120°.

Loose belts, they create an unmistakable squeal, lead to glazing or polishing of the pulleys’ belt interface surfaces, overheating, and plasticization of the belt, all of which accelerate slippage.  If the belt and/or pulley show signs of glazing, a particularly smooth, shiny, and in the case of the pulley an almost chrome-like appearance, it’s a clear indication the belt is slipping. A chronically slipping belt will lead to overheating of the pulley; in extreme cases it may turn purple, which in turn can damage an alternator; extreme heat will travel through the pulley shaft and into the rotor, upsetting the magnetic field, and preventing electricity from being produced.

Slipping belts overheat rapidly, which leads to glazing and plasticization.  Belts suffering from such damage must be replaced, and their pulleys carefully inspected for glazing. New belts installed on glazed pulleys will slip once again, and quickly suffer the same fate.

While an overheated, plasticized belt must be replaced; the glaze on a pulley can be removed using 220 grit Emory cloth, which is used to “dress” the glazed surface, returning it to a slightly rough, satin rather than high gloss finish.  If a new belt is installed on a glazed pulley, it will almost certainly slip, recreating the original problem.

Large diameter pulleys engage the belt over considerable surface area, making slippage unlikely even when belts are under tensioned. 

Where small diameter pulleys are used a notched V belt may be needed.  Small pulleys are often used to increase alternator rpm on slow-turning diesel engines.  Conventional belts can over heat as a result of rapid flexing associated with turning over these small diameter pulleys.

Many serpentine belt systems rely on an automatic or self-tensioning pulley.  Most utilize a square recess, one can be seen here in the center of this image, into which a socket drive or breaker bar is inserted, which in turn is used to compress the spring for belt replacement.

With very few exceptions serpentine belts are self-tensioning, eliminating the most common cause of premature belt failures.  A spring loaded tensioning pulley places just the right amount of pressure on the belt to keep it from slipping, while preventing over-tensioning.  In order to replace a serpentine belt, however, the installer must have a means of compressing the considerable tension exerted by this device’s spring.  This is often done by inserting a ½” drive socket wrench or breaker bar into a square recess in the tensioner’s arm and levering it into the compressed position (and holding it there while the belt is installed, some use a lanyard for this purpose, however, use caution, the spring tension is extremely high, never place your fingers between a belt and pulley).  Without this tool it is virtually impossible to carry out a belt replacement.  Additionally, unlike Most V belts, whose routing is intuitive, most serpentine belts take a circuitous, counter-intuitive path through and over accessory, idler and tensioning pulleys.  Therefore, make certain you make a diagram or take a photo of the installed belt before the existing belt is removed or fails.

This serpentine belt is suffering from both wear and tear, as well as a worn tensioning pulley.  The latter is evidenced by the white filament visible on this belt, the result of misalignment induced by the worn tensioner.

At each replacement, be sure to turn the idler pulleys, as well as the tensioning pulley, each should spin freely and smoothly, without excessive resistance, creaking or squeaking; any of the above call for replacement.  A desirable belt replacement practice involves replacing all belts while dockside, under ideal conditions. Doing so will ensure you have the correct tools and belts. Once complete, save the old belts as spares, as you can be certain they fit.  Many a skipper has been caught unprepared because a spare belt, even one supplied by the engine manufacturer, did not fit.  Be sure to rotate your stock of spare belts and other rubber and soft goods, such as impellers, as these deteriorate storage.

A laser is being used here to confirm proper belt alignment for this alternator, one of three on this engine.

For heavy duty applications, particularly high output alternators, and where maximum life is desired, consideration should be given to using extreme duty belts, both in the V and serpentine variety.  Gates offers a range of belts called FleetRunner™ which are designed for use in ambulances, fire engines, military vehicles and other critical equipment.  Identifiable by their unique green color, they are my belt of choice, and are well-suited for marine use.

Demanding applications require heavy duty belts.  The Gates FleetRunner series, available in both V and serpentine style, used on ambulances, emergency and military vehicles, is well suited to marine high output alternator applications.  Compared to conventional belts, they are thicker and include additional reinforcement.

Belt Fit and Tensioning

Ensure that each V belt’s profile properly matches every pulley over which it turns.  The belt should be even with or stand slightly proud, no more than a sixteenth of an inch, of the top of the pulley walls.  Belt’s whose diameter is too large ride too high on the pulley groove walls, reducing the contact surface area, while belts that are too narrow ride in the bottom of the groove, causing them to teeter, reducing the tension on the groove walls.

Serpentine belt routing is often anything but intuitive, be certain you have a diagram or photo of yours before undertaking replacement.

Serpentine belts come in different widths as well, typically measured by the number of grooves or ridges they possess, which must match those on the mating pulleys.  Ideally, when fully tensioned, a V belt’s tensioning device, an alternator or pump, should be roughly in the middle of its adjustment range.  Most serpentine belt tensioners are marked to indicate their allowable range of motion, which is a function of belt length.  In a very few cases, some smaller serpentine belts used to drive a single device have neither an adjustment nor a self-tensioning wheel; instead the belt is designed to be “rolled” onto the pulley, allowing it to stretch and then retract into place.  Make sure you know if your engine is equipped with one of these, and that you understand the replacement procedure.

The handle of a hammer can be used to push an alternator or pump away from the crankshaft pulley, thereby tensioning the belt for adjustment.

To tension a V belt use a suitable prying mechanism, the handle of a hammer works well for small engines, while a crow bar may be needed for larger applications, as a lever to push the accessory away from the crankshaft pulley, and then tighten the fixing bolt.  Threaded “spreader” bar tools are available to make this task easier, and some aftermarket high output alternator installations incorporate this into their design.  Keep in mind, smaller driven pulleys (found on nearly all alternators) offer less belt contact area, making correct tension all the more critical; loads are high and slipping is a constant issue.  Larger pulleys, on the other hand, like those used for many raw water pumps, offer more contact area, making tension less critical; loads are usually low and they rarely slip.

This belt is too wide for the pulley its driving, the belt stands substantially proud of the pulley, and it fails to make contact with most of the pulley wall, which can be seen by the wear pattern that is too high up the grove wall.  Ideally, the wear pattern should be centered on the pulley wall.

Belts should be inspected regularly (don’t forget the ones hidden under belt guards and generator enclosures), look for evidence of glazing/slippage, guard interference, plasticization, cracking, dust production and improper tension.  Where serpentine belts are concerned the appearance of belt filament, white threadlike material on one side of the belt, is often an indication of misalignment, which is typically the result of a worn tensioning pulley.  As it wears, it tends to force the belt to one side of its own pulley and the downstream idler pulley, causing excessive wear.  A squeal can also be associated with this phenomenon, as the belt is being “wiped” over a smooth, non-grooved idler pulley.  When this occurs, many users simply change the belt, however, doing so will only yield a repeat performance; the problem can only be resolved permanently by replacing the tensioner.

This belt is far too narrow for its pulley, it’s riding in the bottom of the groove, where contact is limited.

Belts are comparatively inexpensive, and thus it makes good sense to replace them every 2 years or 500 hours, whichever comes first.  Remember, a new V belt may require adjustment and retensioning several times in the first 50-100 hours of use; watch for dust, glazing, squealing and chip shedding.   For dust and chip shedding, be sure to clean up the fall out after making corrections, so you’ll know if the problem has been resolved.