really? I didnt realize that, well yeah, that is too much money!

It says a 5 gallon bucket will fill a transom space of 1000 cubic inches, so our transom is 3,000 cubic inches?

I did the calculator, I might be able to find the sheet I wrote down the numbers on.

sounds like you did your homework, so how much is the Marine Plywood way going to cost you?

2 sheets of 3/4" Meranti was $225
I have 5 gallons of West Systems epoxy already
Need to get some 1708 for reattaching the outer skin/beefing up the inner skin where the outboard sits (you can see the 2 holes where the lower outboard bolts pulled through the inner skin).

Break on the transom until I move it indoors at my friendly neighborhood boat yard and knock out the transom. Lots of filling old holes and fairing the console. With the temps dropping the epoxy cure time has gone way up. Adding a little heat (heater in the garage) while I work to hopefully help the initial cure roll along a little better.

For what it's worth, when I was planning mine I posted my plan to use the high-end marine plywood and SHINE suggested that, if I was going to use wood instead of Coosa, I should go with the cheap fir marine plywood instead. He has quite a bit of experience with stitch & glue construction and felt the transom was not the right place for the Meranti. The fir is heavier and harder, more suited for lots of weight and stress. Fir also would hold up better with the eventual water intrusion from holes drilled through it to mount accessories on the transom. I did a little more research and found he was spot on - as usual.
I chose to go with the Coosa but I also slowed my project to a crawl because of the added cost. I will eventually have the rot proof transom I want though (in 5 years, maybe...).
Good luck with whatever you choose.

Fir is over 15lbs lighter per sheet than meranti... (more veneers to create each sheet in meranti than fir)

The whole thing to do is ensure you overbore and fill with epoxy properly, then it doesn't matter what your core material is.

Choose what you want based on what information is available, and what you feel comfortable with :)

2 pieces of 3/4" anything is too thick for doing a 20 transom from the outside. I had to use a 3/4 and 5/8 piece.

So harkening back to the days of yore when boats were built like brick shit houses, things were done one at a time, and by the seat of their pants.

There's many a story of rags and tshirts being found in the foam of Makos, and my SC had a couple screws and nuts and some wire terminals floating around in inaccessible places.

So that is to say, don't count on your experience being the same as someone else on any of the classics year to year. Things were changed on the fly, things were changed because they ran out of something and wanted to finish.

You could fit 2 sheets of 3/4" and a school bus in mine. One experience is not law. ;)

This is correct ^^^

I've done a few 20's and two 3/4" sheets won't work. It's too wide.