Home Ask Steve Ask Steve – October 2014

Ask Steve – October 2014

Hi Steve,

You often see shore cords in the water for a few feet between the pedestal and the boat.  Sometimes it is difficult to keep them clear depending on tides and boat motion, etc.

I never thought of this as a problem because of the thick covering on the cable. Of course, it might be wet or slimy when retrieved, but I always use a microfiber cloth as the Glendinning retrieved it.

I just saw something from the manufacturer of a product called Cable Boom that said this is a problem because it will generate galvanic corrosion. What do you think?

Howard Newkirk

Howard:

Keeping shore power cords out of the water isn’t a bad idea, and if the cord was damaged it could result in an electrocution scenario or a fire.  Thus, while the shore power cable boom device may be genuinely useful for keeping a shore power cable out of harm’s way, a worthy effort, one thing it won’t prevent is galvanic corrosion.

Shore power, and AC electricity specifically, does not cause corrosion, period.  And, if it did, it would be stray current rather than galvanic corrosion.  The latter is the result of dissimilar metals immersed in an electrolyte, not current leaking into water.  Stray current corrosion occurs when DC current “leaks” into the water in which the vessel floats, it attacks underwater metals rapidly, often causing severe damage very quickly, it can even result in flooding and sinking when through hull fittings are involved.

Assuming AC power could cause corrosion, for any type of corrosion to occur, shore power cable conductors would have to be in contact with the water, and if any of the cable’s conductors are in contact with the water, there are bigger problems afoot.  The jacket should be sealed and watertight.

Having said that, plugging into shore power can, via the green grounding wire, induce galvanic corrosion, however, that has nothing to do with the cord being submerged.

Sincerely,

S D’A

 

Howdy Steve,

I would like your thoughts on a subject that seems to have no real answer from the manufactures.

You’re a well-traveled boating person and have experienced various boat hulls in your tenure in the marine industry. Would you mind sharing your thoughts on the old debate between ‘ mono hulls vs. catamaran hulls ‘. Is cost the driving factor in the choice between the two?  For my retirement I have been looking at the 26 ft. to 32 ft. length boats, as a fair weather coastal cruiser between the USA and the islands of the Bahamas.

Respectfully,

Henry Schweinbold

Hank:

Power catamarans have steadily grown in popularity and with good reason; they are stable, comfortable and uncharacteristically spacious for their length. Generally speaking, they also tend to be more fuel efficient than similar size and speed mono-hull vessels.  Up to a point, they pierce through rather than ride over waves, affording them an exceptionally smooth ride in choppy conditions.  Once the waves progress beyond a given point, however, where they begin to make contact with the center span, that advantage diminishes.

The primary drawbacks to power catamarans are imparted by their wide beam, where dockage, and haul out capabilities are concerned.  While a given travel lift may be able to easily handle the weight of a catamaran, its beam is sometimes too great.  Additionally, depending on the design, access to engines can be challenging.

Before moving ahead with an acquisition, I strongly recommend you speak with two or three owners who have operated cats, in the location and manner in which you intend to operate yours.  Ideally, you’d speak with folks who own cats from the same manufacturer from whom you intend to purchase yours.

Sincerely,

S D’A

 

Steve,

I have enjoyed your articles and courses for years.  Recently when starting my Lugger main diesel the oil pressure reads at the top of the gauge and comes down to normal as the engine warms up.   The engine otherwise runs fine and I have changed the oil filter with no improvement.  I have heard plenty about low oil pressure- but high!

Noble Hansen

“Abigail”,  GB 36 Europa.

Noble:

You are right to be concerned about oil pressure; every operator of every engine should be so diligent.  However, in this case I don’t believe you have anything to be concerned about.  You said “recently” implying something has changed.  If so, that is always cause for investigation if not concern.  I assume you haven’t changed the weight of oil being used, or the brand of oil filter.

Initially high oil pressure is common when oil is comparatively cold and thus more viscous.  It’s not unusual to encounter 100 psi at start up, especially in cooler climates.  Provided the oil pressure falls to a “normal” level, somewhere between 30 and 60 psi, there would appear to be no issues.

Having said all this, it is important to ensure the correct grade and weight of oil is used, it should comply with the engine manufacturer’s requirements, as well as making sure the filter is either a factory OEM part, or a high quality equivalent.  Using the wrong filter can create oil flow issues as well as abnormal or fluctuating pressure.  If you suspected the gauge might be inaccurate, and this may be the case if a change has occurred in its behavior, you can easily and temporarily plumb a mechanical shop pressure gauge to the engine in place of the existing electric oil sender.  These gauges are available at auto parts stores, purchasing and installing it yourself would probably be less costly than having a mechanic come to the boat to do this using his or her own gauge (and you wouldn’t get to keep the gauge in that case).  Doing so would confirm the accuracy of your electric gauge, and confirm the oil pressure meets the engine manufacture’s requirements.  Once again, if something has changed then it’s worthy of further investigation.

Sincerely,

S D’A

 

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