Mercruiser Gear Ratio Issue

We are putting three Chevy 350's in a 36' boat with 3 new Mercruiser Alpha One outdrives. This boat will be used to tow (this is crazy) a 65' yacht through the Intracostal Waterway from Ft. Lauderdale to Freeport, Tx. I can order any gear ratio that I want... I just dont know what will be best. We are looking for power, not speed. Any suggestions on gear ratios and prop ppitch would be excellent.

 

1:1.5 would be the usual for that engine size, but since you are towing a 1.65 may be better. You will have to calculate the pitch of the propellers for the maximum towing speed

 

A more unsuitable use for a boat I can not imagine. You say you know its crazy but do you know how crazy,--yet your from a marina. Your towing a 65foot or 65 metre?

Those 3 350's will be running at 1000 or less at 10KNTS, they will foul.

I would not think you could get a lower pitch than 15, your bollard pull would be so huge you would need a special frame to take the tow line.

A suitable boat for doing the job would cost less than one new leg.

I think this is a joke.

 

They make 11 pitch for Mercruiser.

 

would never consider that as a set up
use 2 bravo 2 drives and 2 engines or even bravo 3 drives.

 

Lease/Rent a 40' displacement boat with twin 150 hp or so IB swinging 28-29" wheels.

Using I/O power for this job is a recipe for down-time during the tow. Will require down-time planning and budget.

Karl2