Trinescape, thanks for your comments.
How heavy is your Tri, my aluminium trimaran
is 5,200 kgs.
It is more of a motor
sailer though it does have a sail for downwind cruising.
I would like to economically cruise
at 7-8 knots but have the ability to achieve 15 knots to either get out of trouble or get there before dark etc.
I was a little surprised the Honda 30's did not work better, I run them at 4,500 revs for a cruising speed of 7 knots.
An earlier 29ft trimaran (1,200 kgs) I had, used to do 15 knots with one 25hp outboard
I wanted the reliability
of two motors.
I have considered one large 150hp for speeds up to 15 knots and a smaller 50 hp for economical motor
I like the idea of the bigfoot high trust motors but the largest is 60 hp? and I don't think twin 60hp high thrust will give me the 15 knots speed I am looking for.