Cig41

My drives are 1:1, at Seatek 3150rpm the prop would be spinning 3937rpm. Seems high? At Seatek idle, they say it's 900rpm, I'd be turning the props at 1125rpm. Does your box have a trolling valve?
Thanks much.

999JAY

High that's low, BBC Chevy 6000rpm with a 1.5-1 reduction is 4000 you are right in the sweet spot.
Some are running 1.36 or 1.24-1 to get a greater prop speed.

No trolling valve on mine just shift it in and out of gear around the docks, you might need a vent tube to get the props aerated to get on plane.

999JAY

What hull they going in? have you any photos.

Cig41

I'm completely redoing a '82 Cigarette 41' Attack model. Came originally with CAT3208's with 375hp and BW 73's. Top speed was supposedly 55mph. I purchased without engines. I have post going on the Cigarette forum, several pics there. Moving a little slow, lots of improvements all over the boat are taking place.

999JAY

Looking good what drives you going to use? if you are planning on using #3 I don't know if they will hold up to the Seateks killer torque you might need advise hear.
One good thing about overdrive boxes you are reducing the torque down from the engine to the drive.

Cig41

They are SSM3a's. I agree, the overdrive will help save the drives. I'm not one of those that drops the throttles down, at least not until on plane!
Thanks

999JAY

Seateks make around 1200lbs at 3100 rpm if you overdrive to 4000 this will drop to 850 ish much better for the #3 and closer to the torque of a gas motor.

J

Cig41

I'm coming up with a 22 pitch prop with .80, what do you think?
Thanks

999JAY

With 10% slip it give a TS of 74mph the only downside is you might loose low cruising speed, who needs that anyway I would imagine 30-40 on you will be fine boat might not like to plane below this.