[matt2]

Ok thanks for the response, very helpful.

Originally Posted by sailingdog

First, it would help if you said what boat you have, as there may be issues specific to the make and model of boat you've got.

The boat is non branded, but is essentially an exact copy of the Farr 12.2 m design at least as far as the Hull and keel are concerned. This is an 1980's fin keeler with a modern hull form for that era, but built quite heavily i.e. as a cruiser not a racer. The keel is about 4 feet high and about 10 inches wide at the widest point. The top of the keel is about 6 feet long and the bottom is about three feet. Sort of looks like a wing tip. Not sure what else I can say, I don't have any photos with me. I have owned the boat for 10 years and do all my own maintenance. I have experience with fibreglass, epoxy etc, e.g. successfully re-glassing the rudder.

I have talked to shipwrights about this, but I get different suggestions, some say use a sealant and some say epoxy and then glassing over the keel-hull join.

Originally Posted by sailingdog

Second, not a good idea to use epoxy to re-bed the keel, especially, you'll probably have to drop it again in the future, and bedding it with epoxy will make that really an interesting, in a bad way, task.

But surely a flexible sealant will let the keel move and will crack any faired surface almost immediately. i.e. a faired surface has no strength and is quite brittle, unless the additive can make it flexible? The boat sits on the keel when being slipped, so there will be some flexing.

I do see your point, if the epoxy path didn't work it could be difficult separating the keel and hull again.

Do you happen to know what boat importers use for boats shipped by container with the keel detached?

Originally Posted by sailingdog

Third, 5200 isn't necessarily the best choice of sealants to use. 5200 has an adhesive strength greater than the underlying laminate and is very difficult to remove, again causing any future re-bedding to be more interesting than it should be. It is also not as elastic as some of the other sealant, that might be better suited to the task.

I really want the keel to stay on so I was looking for maximum adhesive strength. The real danger of a crack in the keel is corroded keel bolts and then suddenly losing the keel. If possible I would rather not have to do this again. In any case sealants can be easily cut with a knife to separate the keel and hull. But yes I know it would be very difficult to clean the surfaces afterwards. Frankly I hope this is a once only job.

Originally Posted by sailingdog

You should also inspect the keel bolts for any corrosion damage, since bolts that have sat in salt water for extended periods of time can easily be eroded away by corrosion.

Yes absolutely, I want full confidence in the keel bolts. that is the main reason I want to drop the keel.

Originally Posted by sailingdog

in your Application section, I believe you mean KEEL not RUDDER. Bonding the rudder to the hull would be a bad idea generally.

Yes you are right.

Originally Posted by sailingdog

BTW, most hull-keel joins are faired, but not glassed over. Glassing over the join can seriously complicate repairs.

If I built up the join with two inches of epoxy and matting surely this would be almost like converting to an internally glassed keel. As long as I stripped the gelcoat before this would be incredibly strong. But of course it could still devlop a crack.

Originally Posted by sailingdog

I'm sure that Maine Sail will be along with his recommendations on what sealant to use, probably SikaFlex 291 or something like that...

I look forward to hearing more on this topic as it no doubt affects many yachts.