Since the '70s, I've ordered boat building plywood including Okoume and Sapele from Harbor Sales in Baltimore, MD. They can cut panels to smaller sizes to reduce shipping costs. Multiple sheets come banded together and wrapped with masonite and cardboard, or something similar to protect the outside faces, edges and corners of the panels and are shipped by motor freight to your location. They carry some types and thicknesses in 10' lengths and can scarf panels to increase both length and width if needed.
Suwanee Lumber may carry some of the marine grade mahogany type plywoods as well.
I priced some wood out. Mahogany and Sapele were nearly the same at around 5.50 board foot, white oak only a few cents less, while teak was 5x more expensive at $28/board foot.
Where are you Atlanta/Alabama guys finding marine ply? Only place I could find is Sweetwater Lumber in Austell which has 4x8 marine ply american made/grown fir in 1/4, 1/2 and 3/4. They do not have anything fancy like mahogany. I wanted to put some on the seats to keep my biscuits from burning.
1952 Deluxe Runabout with 1956 Johnson 30hp 1959 Deluxe Clipper with 1973 Merc 500 50hp