Oil filled waterproof housing prototype and prop adapter for 80100

All the parts are milled out of scraps of aluminum flat and round stock. The design is to use a housing to fair the motor which also mounts the motor and holds a seal which will ride on a stainless steal seal sleeve pressed onto the outer housing of the motor. The rear of the motor will be sealed by gluing the cap on the back of the motor with sealant (3m 4200). I will make a pass through with a short pigtail of wires and seal the wires into epoxy and pass them through a fitting that goes into the mast clamp (not yet manufactured). The motor housing will get filled with mineral oil and compensated either with a spring diaphragm or a section of tubing. The outer housing of the motor will be in contact with water which should provide adequate cooling.

The prop is an inexpensive aluminum outboard motor prop listed for engines between 4-6hp or so. The prop was bored out (somewhat poorly because the casting is less than perfect so it was hard to hold) and the hub is a simple milled aluminum feature that is slip fit into the bore out prop and glued with sleeve retainer.

These are all first run parts, although they are less than perfect they should be adequate to prove out the design. The mast clamp will be made in a similar way.


Nice! But looks like a lot of friction. Did you measure the no load current of the pure motor compared to your setup?

I haven’t assembled it yet I need some hardware. There will be some friction but the propellor slip and motor / esc losses for something like this will be pretty high, perhaps more than 50%. If your loosing another few percent to friction thats in the noise.

Very nice and clever