Using the BM3300 engine, pmr260 transmission, boat weighs 18000 pounds full displacement, load waterline34feet, 10 foot beam, intend to use aquadrive coupling between engine and drive shaft.....What will be the most economical cruising speed with this engine and transmission, top speed, what size shaft should I use. It will be monel, but I may have to cut it to size.....what would be the most desireable propeller.
I have assumed a 2:1 transmission. This will call for 1-3/8" shaft. Using 65% blade area ratio prop, 19"x16" three blade Using 50% blade area ratio prop, 21"x15" three blade. This one will give slightly better speed. Most economical cruising will be between 1600 and 2300 RPM. You should achieve about 10Knots assuming a fair hull.
