I have a 14' Zodiac-style inflatable boat with no console or other
provision for instruments, and I want to mount a console-style VHF radio
somewhere on it. The plywood floor and transom are the only solid
items available for mounting things.

I bolted a stainless antenna mount on the inside of the transom for the 8'
antenna, and that works well. The radio works OK just lashed onto
something, but kicking it around and splashing it can't continue.

I would buy a small fiberglass console to mount on the floor, but at
several $100s they seem expensive.

Any ideas? I can work in aluminum and stainless.

I've consider a stainless hoop over the transom; somewhere aft of the
transom would free up scarce space on the deck area.