Beneteau First 235 - O Beneteau Keel Bolts you scare me

The rusty bolts ...weighed heavily on my mind recently. So this winter's project was to remove the keel, have it shot-blasted and new bolts fitted; I've lived with the doubts for two seasons and now it is time to act!

I have removed the bolts and been pleased to discover that my concerns were unfounded! Now others who have the dreaded rusty-bolt syndrome may take comfort from the attached photograph which shows the threads to be like new and underneath that rusty head is actually a very sound bolt.

The washer is beyond redemption, however. The corrosion has clearly come from constantly wet bilges (leaks around stanchion posts - familiar?) rather than a breakdown of anything down below. I will replace them all anyway but feel sure they would have been safe for many more seasons.

So if you have nagging doubts over the integrity of your fin-keeled First 24 (or similar) keel bolts, take them out one by one while she's on the hard this winter (note: they can actually be replaced in the water with one by one method). They are easily removed and may not be as bad as you think. If they are bad replace.

See more amusing comments below by Brian Pickton

Are those actually the HEADS of the keel bolts? Yes, those are the heads of the keel bolts (see below left). Yes, they do get rusty. The keel is cast iron and the bolts are steel so they are compatible in terms of electrolysis. Surface rust on steel is more unsightoly then weakening unless it is extremely advanced.. The relatively mild steel bolts can withstand immersion in salt water where stainless steel bolts, deprived of oxygen, will corrode quickly and are prone to crevass crack corrosion. No, it has not been a problem so far. Unlike some other boats, we have never heard of a keel falling off of a Beneteau. The keel bolts, rust and all, will likely out last you and me by many years.

As to tightening them with a socket wrench, you can certainly give it a try when the boat is on the hard, but don't expect much to happen.. On the hard a large socket wrench with a 4 foot snipe on the handle and two of us heaving for all we were worth would not budge our rusty keel bolts on The Legend, and I would be surpirised if yours moved as well. If you are concerned about their appearance clean them up with a wire brush and paint them with rustoleum paint.

As to tightening them generally, if the boat is resting on her keel on the hard and the bolts move up through the boat, then they definitely need tightening and it may be time for an air socket and major surgery. If however the bolts are (1) flush with the bottom (2) not leaking water and (3) can't be turned with a large tool when the boat is on the hard then ordinarily there is no cause for concern.

By the way , weeping keel bolts don't necessarily mean that the bolts are loose. There is also the question of the fairness of the keel to the bottom of the boat and the state of the caulking to consider. I hope this helps and please do get back to us to let us know how things turn out.

Fair winds,
Brian Pickton of BeneteauOwners.net
Onboard The Legend,
Rodney Bay, St. Lucia

A bigger Beneteau Weighs In

Our 1986 First 405 had what I considered to be badly rusted keel bolts. The 405 has a steel keel with the bolts inserted from inside the hull and the hull to keel joint was separating by about a 1/4 inch at the front (a typical problem for this type of design). The yard investigated by pulling out 4 of them and replacing them with high tensile strength steel bolts (the originals were high tensile steel bolts). None of the pulled bolts had any rust whatsoever on the shank or threads of the bolts due to the heavy caulking in the hull to keel joint. So although the bolt heads did not look pretty, the bolts were not in fact too bad.

Total Cost $600 including labor.

None of the experts I talked to were very concerned about this problem because it rarely leads to an actual failure. Note "rarely", not never. The keel on my boat weighs 8000 pounds and under dynamic loads it could require several times this force to keep it in place. The typical keel is held on with 8 - 10 bolts and each one, if the bolts are sized correctly should be able to take a loading of many times the maximum loading on the entire keel. So there should be quite a safety margin built into the design. It depends though on how much of the head is remaining. You should wire brush all of the rust off and inspect them closely. I would estimate that if more than 25% of the material of the head is rusted away it may be wise to replace it and the large washer under it. To prevent further rusting from the inevitable water that will enter the bilge, you should coat the heads with some form of sealant. Rust priming paint doesn't last. I have used raw lanolin (available in drug stores) recently but it remains sticky and picks up the dirt and in hot weather it tends to run. The next thing I am going to try is to paint them with clear epoxy. On the hull to keel joint we cleaned out the gap as deeply as possible and sanded the rust away in the gap. This is important because if you don't get rid of the rust no sealant will work. We then filled the gap with 5200 sealant and it did not open up the next sailing season. Hope this gives you something to go on.