Project Milo part 3 Fishing boat conversion removing floor 

That flooring you buy it in sheets it's called end grain balsa or core material you can buy it in different thickness the reason for the small square is it's easier to shape into the curves of floor and other parts of a boat. You can buy it from east coast fiberglass supplies.

Microplus 461 same thing at my boat.

I think they use those small squares of balsa with them changinf end grain in each piece, so it prevents twisting id imagine. Definitely an old method

What about part 4 “cutting up & scraping”. Whats left. 😥