What size of plywood?? Transom and Floor

[kickinitoldfool]

So far from what I have read here, most guys are opting to use 3/4" vs 1/2" factory size plywood. Is this correct and will anything have to be adjusted to compensate?

And either exterior grade or marine correct?

And for transom is it just doubled up 3/4" and what is used between them? Resin, Glue or something else?

Thanks all for the help so far.

 

[Georgesalmon]

Re: What size of plywood?? Transom and Floor

1/2" is fine if that was factory size, 3/4 adds more weight you don't need or want. Two 3/4 with titebond or gorilla glue is good for transom. (could even use 3 1/2" and not buy any 3/4"). Exterior grade is good, marine ply more expensive and maybe a little better.

 

[Scott Danforth]

Re: What size of plywood?? Transom and Floor

Titebond III for laminating the two transom pieces together.

for the floor you can go to 5/8" if you really want - lighter than 3/4" and stronger than 1/2"

 

[Captmills]

Re: What size of plywood?? Transom and Floor

I did my transom with 3/4 gorilla glue 3/4 lots of clamps. 5/8 on the floor,came with 1/2 but seemed to thin,end result was that even with the 5/8 the side panels still fit in

 

[coolbri70]

Re: What size of plywood?? Transom and Floor

i used 3/4 doubled to 1 1/2, then 1/2 for the floor except for the bit under the rear bench and splashwell where i used 1/4 as it doesnt get walked on, to save weight in the rear

 

[cutbait76]

Re: What size of plywood?? Transom and Floor

I used 3/4 and Personally wouldn't use 1/2.

With the size of my boat, number of big fish and persons in my family the extra strength I would never give up for the little bit of weight difference..

Say 40 lbs?

 

[HarryO60]

Re: What size of plywood?? Transom and Floor

The deck is part of the boats structure. For the small difference in price and weight it's worth it to use 3/4" plywood.
Exterior grade is fine but make sure you do something to protect it from moisture. There are several choices for protection with epoxy coating being the best and the most expensive. You could also coat with spar varnish or high quality oil based porch and deck enamel.

For epoxies I go to progressive epoxy. Google their name and take some time to read through their website it has a wealth of info on epoxy and how to use it.

Doubled 3/4 ext ply will make an excellent transom and if you decide to epoxy coat you can use the epoxy to bond the plywood together

Good luck with your rebuild

 

[barato2]

Re: What size of plywood?? Transom and Floor

3/4 adds more weight you don't need or want.

this stmt was nagging at me all night. add me to the 3/4" camp. as cutbait said, maybe 40 lbs total (if that) and it's all low in hull and solidly mounted....good things for stability and lowering the CG. the floor is very much part of the structure of the boat; it ties the outboard edge of ribs to the stringers, so it provides longitudinal, lateral and diagonal stiffening. one of our splash o the year winners (NorthBeach) did his in 1/2" with glass cloth added during the resin-ing step and is very happy with the result sevl years later, and this would probably be a good alternative to 3/4

 

[North Beach]

Re: What size of plywood?? Transom and Floor

3/4 adds more weight you don't need or want.

this stmt was nagging at me all night. add me to the 3/4" camp. as cutbait said, maybe 40 lbs total (if that) and it's all low in hull and solidly mounted....good things for stability and lowering the CG. the floor is very much part of the structure of the boat; it ties the outboard edge of ribs to the stringers, so it provides longitudinal, lateral and diagonal stiffening. one of our splash o the year winners (NorthBeach) did his in 1/2" with glass cloth added during the resin-ing step and is very happy with the result sevl years later, and this would probably be a good alternative to 3/4

B I'd like to add a little to that general statement.The floor isn't necessarily structural (i honestly think the boats could do just fine without them). But you're still kinda right if you think about how the floor, ribs, stringers, sideboards, gunwales, dash and transom all get fastened together. It sure as heck has to stiffin things up a good bit.

 

[cj8mule]

Re: What size of plywood?? Transom and Floor

I used 1/2" on mine and wished I had gone bigger. I'm gonna use at least 5/8" on the current project.

 

[JD in Milwaukee]

Re: What size of plywood?? Transom and Floor

I used 5/8" for the floor panels. There was 1/2" in there before. 5/8" seems to work well. I used 3/8" for the side panels.