.
Terry now writes:
Many thanks indeed to those who have so far replied and also for the
information and ideas.
BTW our 9HP in a boat of that weight/style would not seem to 'over
engined'.

If I had a 7000 lb boat, I would feel safer with more h.p. Our
4000 lb. Westerly had trouble in strong headwinds making headway
even motor sailing with the main. We encountered times like going upstream
on the Mississippi where the 7.5 h.p.could not push us upstream. Now we moved
up to a 9.9 h.p., and I feel more secure.



I guess maximum hull speed based on the sq.root of the waterline length
of 21 feet would be about 4.5 to 5 knots?
AIUI, massive amounts of power are required to drive a displacement
hull above 'hull speed'.

Why would anyone ever want to do that? It's totally impractical.

Main purpose of our engine will be to get out
of and into docking spaces. Or, very rarely here, the wind dies!

I don't know how much off shore sailing you do, or if you ever encounter
very strong tidal currents, but it helps to have a strong engine to overcome
currents and strong wind/waves under those conditions.

Sherwin D.


We have also added a 60 to 80 amp alternator to the Volvo while
retaining the Bosch starter/generator for starting only. The generator
was only capable of 8 amps 12 volt DC output.
All the ideas and comments much appreciated.