Interior seat hatch boards.

[Sidnewport]

Anyone know where to buy replacement boards? Melamine-covered high density fiberboard?
One of my interior hatch boards is melamine covered plywood, but it is delaminating. The others have a high-density fiberboard core, and are holding up quite well. All I can find is the stuff made for kitchen cabinets, and those could not take a load.

 

[Loren Beach]

If you refer to the flat covers over the settee storage areas, I addressed these on our 34 footer in a blog entry. Dense as I am, I cannot imagine enough long term moisture to delaminate plywood inside your boat. That would imply a long term leak of "running water" proportion. (?)
Anyhow and apropos of whatever, you might be ahead to just make another lid like I did. While honeycomb paneling might be too pricy new, there are various types of stiff foam panels one can guy, and gluing he Formica on each side is easy. As for "fiberboard", that would attract moisture, and would be best avoided for any use on a boat.
I note that a ton of boat owners are using "Coosa" material for all sorts of medium-duty marine applications, for instance.
Our example, FWIW: https://ericsonyachts.org/ie/ubs/replacing-heavy-plywood-settee-storage-lids.1067/

Regards,
Loren