A little more information would help us to make reasonable suggestions.
Is the swamp boat full size or a model?
How many control channels are needed?
What "normal" radio systems have you tried?
The RC-Model-World has had all this stuff figured-out decades ago, with a cherry on top.
My first thoughts are, what are You calling a "Swamp-Boat" ?
I know what a Swamp-Buggy is,
and I know what an Air-Boat is,
but I've never heard of a "Swamp-Boat".
RC-Controlling anything being operated under actual "Swamp" conditions
is going to be next to impossible.