3/4 flooring?

[Tom Freeburg]

Full disclosure here.  I am building a 25 1/2 Tolman Jumbo, and using Brian’s construction manual as a guide because of the included details.
My question:  I bought 18mm Aquatec, not realizing it is acceptable to use 1/2 for the cabin and fish decks.  Due to the Covid issues I cannot return or even exchange it.  I am probably adding a lot of unneeded weight, yes?  Can I skimp on the underfloor supports?  (I think not)

Any suggestions?

Thx

[Brian.Dixon]

Thanks for the kind words!

Very roughly figuring out the added weight, using 22' of deck that's 8' wide (this is LARGER than what you are doing), I calculate 3.6 cubic feet of extra wood ... at around 40# per cubic feet of fir plywood, that's only about 140#.  Your boat won't even know it's there ... Carry on.  Don't skimp on the under-deck structure.

Brian

[Grady300]

I like the 3/4" for flooring. Gives you more meat to mount things to like seats bases ect.