What is This?

[RUSSELL]

In the midst of the work on replacing the engine in my 1978 C30, I found a quite large gauge wire under the liner/in the bilge. It was not attached to anything - I pulled on it a little and one end came out; pulled on the other side and the other end came out.


There is a bolt sticking out of the fiberglass hull about where the strut attaches - found it when cleaning off the area under where the gast tank used to sit.


Does anyone know why this large guage wire would be there? I assume it did something at some point in time and previous owners removed it for some reason. Is it part of the grounding system? Should it be connected to that bolt? Does the bolt bind to the strut, and hence to the shaft in the water? Scratching my head.

Thanks.

[Dave Neptune]

A guess

Russell, looks like a grounding strap or part of a bonding strap. May be to ground the tank for static spark.

Dave Neptune

[JOHN COOKSON]

Another Guess

If the boat was used in an area where there is lightning it may be part of a grounding system.

TRUE GRIT

[smosher]

could also be a ground plane attachment for SSB radio

[Administrator]

could also be a ground plane attachment for SSB radio

My first thought as well (Dynaplate), but I think they are usually mounted with two bolts, not one.

Bill

[67c&ccorv]

IT's a mold release lasso - in case the hull won't seperate from the mold cause the layup men forgot to wax it.




Good thing the bolt didn't come out!

[RUSSELL]

There is no sign of the bolt anywhere on the outside (on the outer hull). The strut sticks out of the hull, but that is all. Everything else is smooth and unremarkable.

There was no SSB radio on the boat when I bought it.

I did find a good deal of wiring that went nowhere. I think previous owners added/removed stuff and simply left whatever was there before in place. I tore it all out. It just seemed so strange to have this very large guage wire laying in the bottom completely unused.

I thought all sailboats had a type of wiring built into the hull so that the mast was grounded through the the standing rigging and chainplates down into the keel lead. Is this not the case? If this is not the case then is it something I should plan on building in as I go forward. There is some great lightning on Lake Erie sometimes.

Thanks.

[Kurt]

This may be unlikely, but did the boat ever have an autopilot to your knowledge? Since we don't really know that the wire attached to that bolt, maybe it was once connected to an electronic compass that was connected to the autopilot. That is probably a longshot, but the wire attached to my electronic compass looks very similar to that and these compasses are usually mounted in a storage locker near the beam of the boat and down low, close to the bilge.

[RUSSELL]

Kurt,

The boat did indeed have an autopilot - owner before the person I bought it from.

The bolt is low down, close to the bilge.

[Administrator]

I have a fluxgate compass on our boat. It draws milliamps and doesn't require the sort of ground which might be provided by a wire of that size. In fact, the presence of metals nearby is discouraged.

I don't think this was ever associated with a compass/autopilot.

Bill

[jpian0923]

Got a pic of the bolt and location of the wire?

[ndutton]

I'm not so sure the two are related.

The single bolt poking up through the fiberglass is a strut bolt. The popular thinking in the era of your boat was to ground the strut to the engine to pick up anodic protection from the shaft zinc. The strut has 4 bolts, 3 of them are short and below the laminations, the long one is specifically to attach a ground wire. I've installed maybe a hundred of 'em.

Now, on to the pictured wire. It's difficult to be certain but it looks way too big to be the strut ground mentioned above. Strut grounds were typically #10 or #8 and the one pictured looks much larger. As it was left behind by the P.O. and unattached, who knows? It could be anything.

Also typical for the era were lightning ground and High Freq radio ground options. Neither of these incorporated the strut.

Back to the strut ground. If your strut is ungrounded and not showing the effects of galvanic corrosion after all these years, forget about it. It's a non-issue.

[domenic]

Oh, oh...now you're in trouble. Put it back were you found it, and don't say anything to anybody....shhhhh.

It may be for a depth sounder.

[RUSSELL]

Thank you all. I guess it is just one of the oddities that one finds - it must have had a purpose at some point.

This has raised the question of lightning protection. If lightning were to strike the mast (big long aluminum stick forty feet above the water), how is all that energy dissipated? I would think that much current would melt the fiberglass surrounding the strut. Is there a good reference explaining how this should be dealt with?

Thanks.


Funny things are found when one purchases a used boat. I was helping a friend of mine retrieve a power boat he purchased and clear it out. In one of the lockers we found a very large number (more than fifty) of women's underwear in quite a large variety of sizes. I never heard any more about it, but I bet there is a story there somewhere.

[JOHN COOKSON]

One final guess on the wire. Cut it to see if it is a shielded lead. It could be an old antenna wire. Looks much to big to be part of a 12 volt system.

TRUE GRIT