OBoot

"Spy boat for transfering heavy data & money across lakes" ;)
For propulsion accross a lake use fishing rod's reel on the recipient's side ;)
Very stable in water, should withstand small waves. Needs some load for stability.
Designed in FreeCAD.
Cargo of boat is shown on the last picture.
Float test : https://www.youtube.com/watch?v=U_3QFDis8D0