Gearbox/Shaft/Prop Queries

Hi Guys,

I have a Savage Scout that i am putting a 220 hp turbo diesel mercruiser into. The boat is 25 feet and i am looking for a gearbox for it as the engine was originally set up as an inboard outboard.

Could someone please advise what gear ratio gearbox i should be looking for, what shaft diameter and what prop size/pitch i should be using?

The hull is a planing hull, the engine and hull would weigh approximately 5000pounds and the engine puts out 220hp at 3600rpm. Gearbox i am looking at is a Hurth zf63A.

Looking forward to hearing from people.

Cheers,

Nick.

 

What I can give info on is the engine: a VM Motori and they have a good rep,a friend had two and loved them.

They were not overly popular here AFAIK but popular in Europe...should be somebody with parts online in the US..does Merc still carry and Cummins has their fingers in them.

 

boatdiesel.com has calculation software to fit your needs. Their forums are beneficial enough to justify the $25 yearly fee.

 

Thanks guys, have just signed up to boatdiesel.com.

For those that are interested:

I am going to run a 1.5" shaft. If i run a 1.5:1 Hurth 630A down angle gearbox then the prop match is a 17" diameter with 20" pitch. The most suitable combination according to the calculator is 1.2:1 gearbox ratio that would then run a 14" diameter x 16" pitch prop.

Max calculated speed is 31.8 Knots at 13 gallons an hour - this is all theoretical but good information nonetheless.

Thanks.

Nick