swim platform

[toolsinbox]

In the picture you can see the stock swim platform and my boat is the same but with out one.

I need some help and direction in making a swim platform for a 22 ft scarab. I have existing holes partly drilled on the inside of my transom that are for the stock platform that was an option for the 1989 year. I have looked high and low for the stock one but to no avail.

I would like to make it very close to the stock one with no brackets showing.. I want to cut a piece of plywood the shape of the area that covers the transom. A sort of cross section of the platform if you will; and insert bolts through plywood and through transom fusing the bolts to the plywood with some kind of glue ( what would be best ?). With the bolts lined up and fused to the ply; I would then remove the ply and carry on building on a bench.Then glue edge of foam to plywood; extending out away from boat. Mocking up the form on the boat as needed to shape. Then seal foam, then glass it up, then gel coat. The only other detail is I want to shape a recess on the underside to allow for a under mount retractable ladder where I would like bolts to be fused in the glass to accept the ladder. Possibly two strips of ply embedded in the glass to hold the bolts.

Thats my plan---- and now come the questions to the problems I have with my plan.

First of all is this a bad plan?

My first issue is how to glass the foam to keep the plywood from seperating from the rest of the form. Structurally speaking that is. Do I wrap around the edge of the ply and all around the back of the ply? if so is their a techniqe that is used for this? All the attaching hardware will be on the plywood so the rest of the platform cant break off, or its all over!! I guess an easier way to ask this is how to embed the plywood in the glass so it doesnt come appart.

What would the fiberglass mat and cloth schedual be? What do I use, when, where, and how much etc?

What is the best way to seal the foam from melting? I have used waterbased spray contact adhesive and shrink wrap but on much smaller projects. Would elastomeric paint work? (rubbery stucko paint) I have to use fiberglass resin because I have tons of it and I want to gel coat the finish product, so epoxie is out for this project.

Well I will leave it at that for now and any comments and suggestions would be great and I thank you so very much for reading this and helping me.

[J3]

Wellcraft built other swim platforms around this time as upside-down box shapes in a mold - wood only on the transom side and a small lip for stiffness. They weighed around 100 lbs. The sides were built out as well for stiffness and looks. The hollow allowed the drive to tuck up under on some boats an inch or two more. You wouldn't want the lip to catch water, but it was far enough up to never in practice.

If non-fiberglass materials are going to contribute structurally, reconsider epoxy for the best bond. You will have time invested to make this one-off look good.

[yipster]

looks like your ladder doesnt it? build in i think it would look better
here some more http://www.goarticles.com/cgi-bin/showa.cgi?C=1313021
havent read it all but like to mention keep the weight down or you'll get nose-up

[SharkFM]

Carbon fiber is the best. Man it is strong and so light.

I used a fir base to hold the screws and rest of this platform is built like a surfboard but using CF. Weighs like 7 lbs vs. the stock 30lb!

Pix of Carbon Platform
http://twitpic.com/2u7jzn

http://twitpic.com/2htmsf