Thanks everyone for the interesting replies,
I should have mentioned the Tug I'm researching is a large scale, big model around 30 inches of a Log 'Bronc'
the majority of full size caft are Schottel/Z/Outboard drive - that spin around on a sixpence,
leading me to think schottel drive for manouverability was the way to go.
The short, fat, deep hull with fluid dynamics of a house brick needs big brushless power to motivate the thing
driven in the manner of the full size craft with lots of full power forwards switching instantly
to full power in reverse - I'm thinking will quickly lead to wrecked gears etc.
A good comment has been mentioned about using simple, reliable and powerful old fashioned steerable nozzel,
and I have found a photo of a full size Bronc with conventional prop and nozzel that fits the bill, may go down this route.
While working on the plans, I'm trying to stop myself looking at the wonderful but hideously expensive $500+ Bauer all metal
Schottels for sale on the other side of the planet,
the price of these beauties plus good old uk import tax etc etc ? It would be good sense investing a new lathe !
regards Paul