Float??
LOL
That's an idea for a mod for DTR's an amphiDTR (amphidator).
The chunky tracks might be big enough to act as paddles already.
I've just ordered some PolyFoam - spray it and it expands, seals, insulates etc..
Also ordered some foam sticky backed pads for sticking around the gear housing section.
I'll let you know if it makes it any quieter.
Or how hard it is to remove all the foam if it doesn't work.