Hehe, I already have that video, its brilliant. That must be like a 4ft long tub. Thats a little on the big side for me to just carry around.

Maybe somewhere along the lines of a motorised buoy, kinda like fishers use, but 100 times bigger. A bucketsize pill.
Perhaps I could use two 800size motors and put in a 12v 7A Pb battery. That should give enough power to beach a whale.