prop advise.

[stratcat88]

i have a 1985 mercruiser 260hp with alpha 1 drive on a 1985 chriscraft scorpion 254.it came with a 15" alum.prop and a spare stainless steel 17" prop. dont care about hole shot, just want some speed on plane. also have ben. trim tabs. boat for fishing in atlantic and weekending. thanks.

 

[steelespike]

Re: prop advise.

Do you know your gear ratio sometimes on the out drive. What is your present lightly loaded performance like with say the 15" prop.
Wot rpm and gps speed.

 

[stratcat88]

Re: prop advise.

Do you know your gear ratio sometimes on the out drive. What is your present lightly loaded performance like with say the 15" prop.
Wot rpm and gps speed.

i just had another motor installed and have just a few more things to fix befor it goes in the water. i will get back with you on that. thanks

 

[jestor68]

Re: prop advise.

Your gear ratio should be 1.5, unless it has been changed.

I would test the 17" prop first if interested in top speed.

The WOT rpm range (originally like 4200-4600) will depend on what year/model motor you had installed.

 

[Chris1956]

Re: prop advise.

That is a lot of boat for that single V8. It is a good thing you have the trim tabs, or it would be hard to get on plane with some friends on board. The optimum set up will be to prop it to achieve plane (with some reserve power), with the tabs down and an average load. That should give the best top speed.