Using foam to reinforce things....

[chewy]

I want to fit some knees to my transon as the original stainless ones are missing.

Will any of the following foams be suitable:

http://www.cfsnet.co.uk/acatalog/CFS...RIALS_129.html

Is it the wood in the knees and transom that give it strength or the fibreglass that covers them?

[Dirk Diggler]

It's a combination of both, although with enough glass the wood or foam don't matter.

Foam is easier to work with, but wood is easier to laminate to.

[9D280]

Wouldn't it be quicker & easier to get a couple of lengths of stainless tube, then 20 mins use of a large hammer & a 10 (I think) mm drill & you replace the original braces? Alternatively even quicker (but probably 10 times the price) do Avon or an aftemarket place sell them as "bolt on" spares?

If you do use foam, don't do a "Dell Quay" and end up with the heaviest set of knees ever created. (i.e. Make sure you use closed cell / non absorbent foam!). Also the key with any bracing is to make sure it's properly attatched - if you're going down the knees route that means make sure it's properly bonded to floor and transom or you might as well not bother.

Having once used a "'glass knee" reinforced SR4 I really missed the braces at the stern for mooring alongside, towing, tieing fuel tanks down........ Personally, I'd just replace the stainless braces, but that's just me!

[Searider]

I replaced the ones in my 5.4 as they had been replaced with a horrible frame for mounting tanks in. Got them from a local Avon dealer. About £80 for the pair if I remember correctly. (6 or 7 years ago).

If the studs that are embedded in the sole of the boat are in good condition and secure then, although not the cheapest way, this would be the simplest solution.

Be careful of the nut size / thread pitch for the stud. Nothing metric that my chandlery had would fit my 1978 boat - fortunately I kept the ones I took off and could re-use them.

[chewy]

What size pipe should it be and whats the wall thickness?

I think I'll still go down the glassed in knee route as it looks tidier.

[codprawn]

i would use wood for the knees - liberally soaked in epoxy first. I would also put long dowels right through from the transom - also liberally soaked in epoxy.

[chewy]

Cheers for that, never thought of the dowels.

[Dirk Diggler]

Originally Posted by codprawn

liberally soaked in epoxy first. I would also put long dowels right through from the transom - also liberally soaked in epoxy.

Why?

[codprawn]

Originally Posted by Dirk Diggler

Why?

To give extra strength and reduce the possibility of water ingress - thought it would be obvious really............

[Jono]

Originally Posted by codprawn

To give extra strength and reduce the possibility of water ingress - thought it would be obvious to a know-nothing, idle boat builder..really............

.............

I'm assuming Codders means to "plug" the holes left by removal of the bracing bars ......