Twin Fin: Keel Bolts

[NigelBirch]

Am I right in thinking that, with a twin fin on a drying mooring, all that banging up and down will eventually cause metal fatigue and failure in the keel bolts. And if this is true, does one ascertain their condition or simply replace them every XX years?

 

[Niander]

If its soft mud/sand there shouldn't be much banging happening...be more concerned about corrosion of bolts...

 

[gandy]

I've never heard this as a general issue. I suppose it may depend on the type of boat, and thus the type and material of the keel bolts or studs. Normal checks with the boats I was looking at would be for signs of movement of the keel/hull joint, and for corrosion of the studs.

 

[Birdseye]

Your boat suffers more if it sinks into softish mud rather than standing on firm sand, apparently.

I would be surprised if the keel bolts ever suffered fatigue failure - the load on them should never get that high. What will happen is that they can work loose.

Maybe best to ring a surveyor or two. Most will help with the answer to a question like that, though I've yet to meet one that would understand the metallurgy