Re: Boat Speed?
I think it might be a reasonable estimate
By my calculations, use a constant of 150 for a tri-hull boat.
don't forget to deduct 10% of your horsepower if you have an older (measured at the powerhead) motor.
I agree, reasonable estimate at best. If I plug in your 150 as a constant with the 100hp set up I only get 35mph, short of what the boat did with just a 60hp motor. My set up on the boats is not good as they could be. We have the motors set as low as they will go and run SE sport foils on them. Since our main useage is watersports, I have them set up for holeshot and tight turning. I'm sure there is more speed with a little tweaking, but I don't need more speed on our 160 acre lake (doesn't take long to get from one end to the other as it is)
Also, I did reduce the hp on the 1981 90hp, the other two motors are 1988-1989's so they are propshaft rated already.
