Im going to make a foam transom, hey techno!

[aircraftman]

techno. i like the job you did on your seats and im going to make my seats that way!! sweet!!!

i need some advice on the transom though. i was thinking of removing the transom from the inside all the way to the glass under the gel then laying up 3 layers of 1/2 divinylcell with a sheet of kevlar in between them and .050" alum sheet on the insode covered with kevlar. ging to use your insert idea for the bolt holes.

any comments on this?????????

[H2Onut]

DONT DO IT, faom in a transom, it will compress when you bolt the motor on. use transom cast and sandwich a piece of aluminum in it.

[Georgia Boy]

don't use the foam in a transom use either an epoxy or wood, foam compresses. and I am not sure it would spread the load well either.

[aircraftman]

if you put inserts in the bolt holes they wont compress the foam.

BUT the load distribution may be a problem.

DAM THE MARINE PLYWOOD!!!!!!!! it always keeps creeping up as a good way to go no matter how we try to better it.;)

[Georgia Boy]

if you use marine plywood, which i personally like for a transom, Cut each peice and completely wrap and seal in glass, I wrap mine good before i install. then glass the pieces into the transom you still can glass in the inserts to seal off the holes completely, that was you will not get water to the wood. if you do that then i doubt if you will ever have another transom job to do on that boat as long as you have it. also something I have not tried yet but heard a good deal about is this casting stuff, not sure on the wieght of it, but plenty of people on here can. you transom is not a place to sacrifice strength for wieght in my opinoin

[Techno]

I know nothing of foam transoms and am afraid of engineering one myself.

The foam transom is done by eagle one - they have a picture on their site. And I think Allison.

I have to agree with Georgia Boy, use plywood and finish it outside the boat. Seal the holes after its installed and it won't rot.
Everyone is looking for something better than wood and there isn't anything out there. Every material has its strong and weak points or compromises. Wood has the best of the most and little of the worst. You add the needs up and fit the material that best fits.

I like the idea of installing pipe nipples in for the engine. It supplies a 360* connection to the inside of the transom as well as the compression clamping, and it seals the hole forever.
1" diameter- 3.14*1"=3.14 sq. in. times the 2" or whatever transom thickness is 6 square inches of bond to the transom per bolt. Without them you only have the bolts compressive force on the transom. With them you also have an actual bond inside the transom.

If any one wanted they could bond a pipe nipple in a chunk of plywood and measure its draw strength on failure. West epoxy did this for bolts and it was enormous. Eventually the depth is large enough for the bolt to break, not the wood.