Keel bolts on potential purchase

[jwilson]

Have you ever seen an attempt to "...draw a keelbolt for inspection" on a modern GRP production cruiser following a surveyor's few words recommendation to do so? It will either be dead easy and apart from the (possibly trivially surface rusted top of a non-S/S bolt or stud) be perfect, or it will be a complete nightmare - not wanting to move - till you get rounded nuts and still not out.

Similarly fully removing a typical AWB keel surprisingly often means serious GRP work repairing gelcoat and structural GRP as the adhesive used to joint the keel is stronger than the gelcoat/laminate interface.

I'm not saying modern AWB build quality is great (it is good for the builder, not for later systems repairers who have to access lots of stuff fitted before the decks were put on), but keelbolts really are not usually a problem. As others have said, they were on wooden boats, but not any more unless on a hard-raced boat the hulls have had multiple unacknowledged at-speed groundings whilst racing.

 

[Tranona]

@Tranona does your optimism on the lifespan of keel bolts stem from an assumption that modern boats have dry, dusty bilges? Or is there more to it that that?

No. Water in the bilge is not usually a cause of corroded keel bolts unless (like on your old Moody) they are mild steel which can look a real mess, although the studs themselves are usually fine. The dry bilges are because most boats in the last 30 years or so from the volume producers have either saildrives or Volvo type dripless seals. so no steady stream of seawater into the bilge every time the shaft is turning.

Almost all keels are over engineered (with the odd mistakes!) in both the supporting framework and the scantlings of the bolts following the ABS standards. In addition they are glued on. Corrosion occurs at thee keel/hull interface and water can only get there if that seal is broken, almost always after a grounding when the gap can open either at the front or rear of the keel. That is what started the process which led to the foundering of Cheeki Rafiki I referred to above. Poor repairs after groundings leading to water getting into the joint.

This style of keel attachment (stainless studs into iron or lead keels with adhesive sealant is largely post RCD (1997) practice. Before that mild steel was common as was non setting sealant plus poor castings and inadequate bolt layouts meant joint sealant failure even without grounding. The article in post#14 reflects that as poor keel attachment was common in the US.

This havenharbour.com/bavaria-keel-install gives you an idea how massive the keel and bolt structure is on a modern boat. Many boats are shipped from the factory without keels and rudders to reduce shipping costs or because they are too high for road transport. So they are designed for the keel to be attached at the dealers. My Bavaria was low enough for road transport to the Hamble, but most over 40' with deep keel would come without keel and rudder.

In summary, older 30 years+ fin keel boats are more likely to have keel issues because of the method of construction, and most fin keel boats are vulnerable to grounding damage. In the absence of grounding or signs of keel joint failure it is unlikely that there will be any issues with keel bolts.

 

[ducked]

Have you ever seen an attempt to "...draw a keelbolt for inspection" on a modern GRP production cruiser following a surveyor's few words recommendation to do so? It will either be dead easy and apart from the (possibly trivially surface rusted top of a non-S/S bolt or stud) be perfect, or it will be a complete nightmare - not wanting to move - till you get rounded nuts and still not out.

No, but there are descriptions on the Trident Owners Association of exactly that, with the implication that you shouldn't do it without symptoms, which are rare on that boat because of the way its put together.

Symptoms (primarily keel gaps and rust streaks) seem to be less rare on old boats in general, but these are not the focus of the OP's interest, which is the 90's, Collapse of the USSR, Safe-Sex, Dot-com Bubble, Beneteau.