Keel Boats - to bond or not to bond

[tillergirl]

Knocked out a couple of keel bolts today (he said casually as though there was nothing to it!). The first one out in way of the mast support determined me to knock out the rest! Top half was quite badly wasted to half its original width! The second one further aft was not badly wasted but the bottom nut was more symbolic than actual. Now they have been there for over 40 years without bonding. When the new ones go in should I bond or not. If I get another 40 years with the next set, I'll be 97 so I guess it will be someone else's problem.

I'm inclined not to bond on the basis that 40 yrs life isn't bad and the keel wasn't about to drop off anyway. If I bond I might upset the balance and start something going quicker.

What do you all think?

 

[Coppershield]

Hi Tillergirl,
I usually refrain from answering technical questions, without being there
it is possible to give wrong information. Here's my two cents, please take it for what it is worth.

What are the materials that is used in your yacht's construction (hull-material, keel material, type of materials involved with the running gear etc.)
Assuming Your yacht is built with GRP and the keel is cast iron, if it was my boat I would bonded but not for the reason you are inquiring about.
My reason for bonding it in our area would be for the enormous number of lightning strikes we get in Florida.
If the lightning was not a factor, I would not bond the keel bolts. Reason being this will not provide any protection to most yachts but in certain circumstances it could create more problems.

Again if it was my boat and the lightning was not a factor, I would replace the questionable bolts with a slightly more noble material then the keel material.
Additionally if you can be sure the interface between the hull and the keel is totally watertight You could mount a small anode in the center of the bolt pattern.
Friend of mine has a boat that has external keel and a very shallow bilge with the standing water problem, addition to bolt changes I have recommended that we make a small cover over the bolts to keep them watertight, for this I have recommended using 1/8 of an inch thick polycarbonate(clear)
I'm sorry for being long-winded I hope this will help
Regards
Muzaffer Develioglu

 

[chippie]

A simpler answer is to stick to what has known performance. In my opinion bonding would be stepping off into an unknown area. As long as you replace the bolts with the same sort, the performance should be the same as those which lasted 40 years.

 

[tillergirl]

That's my thinking at present.

 

[Ships_Cat]

And very wise thinking too, in my opinion.

John

 

[tillergirl]

Thank you for the helpful answer. Timber construction, 1" iroko on Oak frames, copper fastened, Cast Iron keel, steel keel bolts 1" diameter (studs with nuts both ends - don't like that at the bottom, may get proper heads made), rudder heel fitting is steel, prop shaft is stainless, stern tube is bronze, all screws (hood ends) are silicon bronze. Bit of a mixture when you write it all down.

The moment I add lightning is not a factor, I shall feel twice as vulnerable, so I shall just note your point!

I am thinging about some bronze replacements for the keel bolts but I'm not sure the added expense is worth it given the performance of the old stuff up to now. That said, of course, she now carries more electronic stuff, battery power etc than she did in the first 25 years of her life.