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bugged 03-26-2002 09:15 PM

Hi, I have a 26'' boat with a swing keel. I have just gutted it out & one of the first things I was going to do was the wiring. I purchased & read Don Casey''s book on wiring a sailboat.
Here is the problem(s).
1. He says to ground your house batteries to the engine so the ground will be in contact with the water through the propeller shaft. I have an outboard that when not in use, does not touch the water.
2. He says for lightning protection you should ground your mast to the keel with a #4 wire. My keel is a swing keel that has the pivot point outside the boat under the waterline, so attaching to the keel is out of the question.

Any advise would be helpfull.
Thanks, Larry C

sailnby 03-27-2002 02:55 PM

Several years ago I had a similar situation on a Hunt 17 swing keel with outboard. The boat was on a fresh water lake near Ft Worth TX so the lightning issue was major. I ran 1" wide copper as my ground buss for radio, house lights, etc. I kept the buss isolated from everything not using house batteries. Two lengths of 15'' chain (with a large battery type clip at one end) was modified with a piece of #4 copper wire. The copper wire ran nearly the entire length, was soldered to the chain at 1'' intervals and trimmed to make a fine point at the end. I would attach the clips to the shrouds on each side and drop the chains in the water as a storm approached. When possible I would try to get the chains on the bottom (in the mud). Never had a direct strike and never fried any electronics in five years of that kind of sailing. My current boat is setup the way Mr. Casey suggests, however this boat has an auxilary engine, deep fixed keel, galvanic isolator and is in salt water. Hope this helps. Greg

VIEXILE 03-27-2002 03:51 PM

Get a Dynaplate sintered bronze ground plate. Two 1/4" bolts hold it in the hull, so minimal drilling. The bolts serve as attachment terminals for VHF ground and lightning grounding. I''m not convinced that you can get away from direct strike results. I still let go the helm once in awhile when the flash occurs. A lot of people think there''s some magic bullet for lightning, but "protected" boats that do get hit still get fried.

Pangaea 03-27-2002 04:22 PM

You can install a grounding plate near your centerboard well and run the engine ground to that. Now it doesn''t matter if the engine is up or down
2. Install another ground plate straight below the mast(electricity doesn''t like to turn corners). Now run your no. 4(at LEAST no. 4) to that. I think the best way to avoid a lighting strike is to avoid a lighting strike. This can be done by not allowing the static electricity to build up. Lightning just doesn''t strike, it is "provoked" by static electricity building up in your rigging and then jets skyword in the form of a streemer luring the strike. A electrical engineer told me the best thing to do to avoid this is to cable clamp a no. 6 tinned wire to the upper shroud base on each side of the boat,strip 6" of insulation off the other ends, solder up those ends and simply drop them into the water. (I''ve done this on my boat).This gives the static electricity a chance to bleed-off thus preventing a streemer thus preventing a strike. But remember, there are no absolute guaranties against a lightning strike.

Dennis L.

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