20SF transom thickness
 

I know the standard layup for a transom is 2 x 3/4" core = 1.5" total. Is there any downside to making it 2" think? I found a really good price on 1" coosa bw26 locally. Also, any thoughts on using it for the deck as well vs. honeycomb (nidacore) other than weight.

You just don’t need two inches. try using the inch and a half thick coosa board works great for me

How good is real good ? Mr reeltherapy sir ? on the coosa that is .

I don’t think, you’ll hurt a thing going with 2” of core. You’d gain stiffness without adding much weight. It is overkill, but what’s the problem with that.

2” for the deck is f’n crazy. Coosa recommends matching the original laminate thickness. Nidacore or divynecell are fine for deck.

Mshugg. 2” for transom not deck , 2” does seem a little over kill but hey nothing wrong with overkill.

The biggest concerns with a 2" transom core are that the thicker transom may cause other parts to not fit like a cap with stern wells, motor well, and some through transom fittings or transom mounted stuff like steering components.
For some motors (and most I/Os) the max transom thickness is 2.25"; with a 2" core where you have bonding between the two 1" layers plus bonding to one old skin plus one new skin, it is real easy to get way too thick. If you plan ahead well you can grind out the areas that need to be thinner but Coosa is made with mat embedded in both sides so you probably need to make up for that in the ground out areas. Wear Tyvek and a good respirator plus glasses/mask when grinding or shaping Coosa - I speak from painful experience there.

a few pounds of extra weight from the thicker core is trivial

Have fun!