I did look at real bilge pumps. After removing most of the housing of the smallest unit, It was still to big for my 2 ships.

As suggested, I took a hammer to one of the units. The rotor is a solid ring of magnetic material. It is a 1.5 mm thick ring on the SS shaft. It has one side North and one side South.

The AC component is a C shaped core of soft steel lamentations like a transformer. There are 2 cores of fine wire wired in Series. The ends of the lamentations are semi circular around the cavity for the rotor of the impeller.

It is effectively a 2 pole armature and a 2 pole stator.

Thanks for all the good ideas. The pumps are required to run for about 5 hours every month.

Regards,

Bobby Clark