Transom 3 or 2 layers ?

[Wallman67]

I'm trying to build my transom to 1 1/2 thickness. As I already have some 1/2 marine plywood, can I use 3 layers glued together ? It comes up about 3/16" short. Is it a big deal to build up the difference in glass it and glass it into the boat anyways ? Or would it be better to go pick up some 3/4 " and save the 1/2 for the stringers ?

 

[lowkee]

Re: Transom 3 or 2 layers ?

3/16" is a lot of layers of glass, maybe 7-9 layers of 1.5oz CSM. Woven roving may fill the void quicker. I'd opt for getting closer to thickness via plywood. I used a piece of door skin (luan) to span the gap, but I have no idea how it'll hold up, so I'm shy to recommend that procedure.

 

[83ProLine]

Re: Transom 3 or 2 layers ?

1/2" of core plywood for the transom sounds really thin. What size boat do you have?

The short answer to your question is it is not necessarily the number of layers used, but the way the wood is tabbed in.

I have a 21' Center Console and I used two 3/4" sheets of plywood that I laminated together, then three layers of 1708 bi-axle tabbing, then a couple full sheets of cloth.

Regards,

James

 

[kenny26]

Re: Transom 3 or 2 layers ?

I agree most transoms are 2 layers of 3/4" inch ply. Although my boat had a piece of 1/2" laminated to a piece of 3/4" but my boat is only rated for 50 HP. The runabout renovation book suggests each layer of CSM nets about 1/16 of an inch. So if you lay a layer of CSM between the skin and transom, and one layer of CSM between each ply you should be real close by the time you add a layer or two on top, especially if you tab with roving. IMO I'd go for 2 layer of thicker plywood .vs. 3 layers of thinner stuff. Take note that you're better off having the transom a 1/8 or 1/16" thinner than the original (assuming a fiberglass boat) otherwise if you go thicker you may have trouble getting the cap back on.