Keelbolts

[andrewg]

Just how do you go about getting keelbolts inspected? I have a 1966 Sparkman & Stephens with a long bolt-on lead keel. The bolt heads look OK, some sort of bronze. The surveyors I have spoken to are fairly derogatory about x-ray or electronic methods. Extracting bolts (there are 14 of them) is such a huge job I probably can't afford it. Is there a way of inspecting keelbolts without spending thousands?

 

[Guest]

It used to be considered sufficient just to draw a couple for inspection.

Even an x-ray would be useful to prove to your insurers that you undertook proper maintenance - someone on this board mentioned a claim involving old rigging being turned down on those grounds.

 

[Plum]

At the very least, take out one. Based on the condition of this one you should be able to make a judgement on whether to do the lot or put it back and inspect another one in, say, 2 years time.

 

[andrewg]

Thanks for the advice. The next problem seems to be that the keel bolts are upside down. All I can see at the top is a screw thread and a large nut at the top, implying that the head is embedded somewhere in the lead. Is this normal? To extract a bolt would surely require hoisting the boat about 3 feet off the ground so the bolts could come out, if indeed you could ever find the head. Even then, I don't know how you'd get them out. I would welcome advice on the practicalities of doing this. Maybe an x-ray is sufficient.

 

[brianhumber]

Suggest you manually extract at least 2/3 per year. NDT in situ is good only if done with the right equipment. I have tried these methods on behalf of my company and you need the right equipment for the right application. The kit can be hired but hire costs for the type of examination needed for keel bolts would cost several hundred pounds.

 

[vyv_cox]

Although called keelbolts they are more usually studs. Extract by tightening another nut onto the top of the existing one, applying compression force to both with spanners and at the same time applying an overall unscrewing torque. It sounds complicated but it's not too difficult when you have done it once. The complete stud should unscrew upwards from the keel.

 

[Adrian_Morgan]

I assume the boat is wooden. But it makes no odds. If you extract a bolt, choose one that is as inaccessible as possible. It makes no sense to draw the easiest bolt for checking as it may have been drawn for the same purpose before. Then again previous owners may have read the same advice...

Drawing a bolt or two is no big deal. If it's bronze in lead then it should come out sweetly whatever the condition. Unlike a corroded iron bolt. Surface condition is no indication of internal condition. A sharp tap with a hammer on the (cleaned) bolt, suspended from a piece of string, like a chime, should cause a clear ringing sound, but even that's not infallible.

If the bolts are original circa 1966, then they will undoubtedly be suspect. You say there's a nut on top (presumably atop the wooden frame). That's how it's meant to be. The end embedded in the underside of the keel may be in the form of a V-shape, which is common, or it may have a nut (brazed on). This will also be embedded flush in the underside of the lead keel. In some cases the nut may only be accessible via a side channel (plugged with a wood block). In this case the nut will be free to unscrew.

S&S may well be able to give advice on how the keel was fitted. Forget X Ray.

But above all, don't imagine it's a difficult job. Common sense. You'll need to lift the boat, obviously, a few hours in a travel hoist or even in slings would be enough time to check, but don't take them all out. Like batteries in an organiser, leave some to take the strain!