I want to make a bow thruster to my model boat. It is made with
two aluminum tubes, two ball bearings, a sealing gasket and a shovel.
The two ball bearings are a little too big for the aluminum tube,
and so I split it. This also facilitates the mounting of the ball
bearings. The pipe is filled with grease so that the water does
not enter. The split in the pipe is made with a cutting disc (1mm).
It is all glued with epoxy. This is a prototype and I will make
small changes eventually.