Keel bracing - Any suggestions ?

T25 · Post by **T25** » Wed Mar 05, 2008 11:31 pm

One job I need to do to my boat is to brace the insides where the keel bolts go through. I know it needs doing because too many Debutantes end up with one keel dropping off. The question is, which wood to use ?
If I use hardwood the stiffness may distort the hull, but if I use softwood I have the potential problem of rot setting in.
Any ideas or comments ?.

chakalo · Post by **chakalo** » Thu Mar 06, 2008 4:16 pm

Right..standby your bunks..this will have the chippys and pro boat builders foaming at the mouth..

T25, have you seen what is used for outdoor tables and chairs at some of the junk food places, Mac's etc:? It's a sort of high density plastic moulded to look like wood, 100% water/rot proof. You can saw and drill it easily. I've seen it used to clad RSJ's to make them look like wooden roof beams and my oppo used it to make 'runners' on his lauching trailer, works a treat. I understand it's available in 2x4 etc:(or what ever the Mickey Mouse measurements are now) might be worth a look mate.

T25 · Post by **T25** » Thu Mar 06, 2008 4:25 pm

That will no doubt have them foaming at the mouth

Good thinking, hadn't thought of plastic wood

Rowana · Post by **Rowana** » Thu Mar 06, 2008 4:33 pm

I would have thought that there would be a solution to this problem if, as you say, there are a few boats with the keels dropping off.

Is there not an owners site, or somesuch, where this has been discussed and solutions expounded already?

Just a thought.

T25 · Post by **T25** » Thu Mar 06, 2008 5:05 pm

I've found quite a few entries mentioning the reinforcement but nobody seems to want to say what they've used, and the boats that loose their keels seem to be just left to rot. They're lovely boats and a few of them seem to have completed pretty stunning trips, but the ones that aren't looked after are the ones that end up damaged, and often rot away before someone gets in to repair them. So no, nobody seems to have asked the question before, and there doesn't seem to be a definitive answer yet.

Rowana · Post by **Rowana** » Thu Mar 06, 2008 9:21 pm

This bit, which I assume you've seen is from "Classic Boat" -

"The bilge keels are made from 3/8in mild steel plate, and can be a weak spot as they often break off. They are bolted onto longitudinal ply stringers on the hull and rely heavily on the flexibility of the ply FOR WHAT, EXACTLY. The older the ply gets the more brittle it becomes and it will need beefing up." (My red bit)

From the above, it seems to me that the problem is that the ply becomes brittle with age. This also suggests to me that simply replacing the ply will be sufficient.

I'm no boatbuilder, but in my (very) limited experience, if you make something too solid, it simply transfers the stress somewhere else.

Have you tried emailing the original designers to see what they would recommend? here - info@tucker-designs.com

HTH

FullCircle · Post by **FullCircle** » Thu Mar 06, 2008 9:59 pm

Bread boards from the Pound Shop?

Arghiro · Post by **Arghiro** » Thu Mar 06, 2008 10:03 pm

Angled keels settling in soft deep mud may be the reason why some flexing is advisable. Has been a problem for some Centaurs as well.

This would imply that rigid reinforcing may not be the best solution.

Post by **Silkie** » Thu Mar 06, 2008 10:41 pm

How about glueing in some additional longitudinal stringers either side of the keelbolts. Don't make them as stiff as the originals so that the hull will still be able to flex in the places it was designed to flex - just not so much.

I did something similar in an old Mirror with lengths of DIY shed hard(!)wood where the aim was to stop the alarming cracks coming from the 40 year old plywood hull when I stood on it.

T25 · Post by **T25** » Fri Mar 07, 2008 12:27 am

Rowana
I have indeed tried asking for advice direct from them but have yet to get an answer, but replacing the ply as a whole would only delay the problem, so bracing has to be done some time and I may as well do it while it's out of the water.

Jim
Nice idea, I like it, but there isn't enough room to fit them in.

Arghiro
As far as I can tell, that is what happens. Over here there are loads of sand and mud flats and the keels sink in at an angle, which does apply sideways pressure so a certain level of flexibility is vital.

David
You don't say if it worked ?. That's the problem with plywood boats, they have to flex but ply doesn't retain that ability indefinately, and then you need to control the flex a bit but not too much

Post by **Silkie** » Fri Mar 07, 2008 12:44 am

It worked well, unlike your avatar - unless it's a little white square with a red cross.