first boat prop help

[zachfarmall]

I have an 84thundercraft 160 16ft trihull with a 1984 60hp mariner 2stroke and I need a prop.there is no pitch numbers on current prop.its gonna be for fishing and pulling a tube.I believe wot is 5000-5500 rpms.thanks

 

[Sea Rider]

Welcome to Iboats,

What's the matter with current prop, if in opt working cond you should tach prop to check if inside min-max wot rpm parameters stated for that engine and go from there for a prop maximization to suit your boating needs.

Happy Boating

 

[zachfarmall]

The prop is beat to hell and the boat doesn't have a tach

 

[Sea Rider]

If that engine was factory delivered with a installed prop should be a medium pitched one which works top on light applications and well on medium ones. On heavier ones will need a prop maximization. Will need to contact Yam dealer and ask them what's the standard factory delivered prop size for a 60 HP engine, or take prop to a prop shop to have it measured.

Is it possible for a good prop shop to repair actual prop, if so, can go from there maximizing other pitch prop for your application, but with a Tiny Tach meter if tiller steered, If you have a center console, install a Yam tach and play with prop pitches all you want.

Happy Boating

 

[zachfarmall]

Does a 10x 13 sound reasonable to start with

 

[steelespike]

Have you looked under the prop nut?

 

[zachfarmall]

I haven't. I didn't think think it would be there.I will check tonight

 

[steelespike]

If no numbers under the prop nut a
13" pitch is a reasonable starting point. But not knowing your typical load and the dry weight of the boat we're going in blind.
If we are going in blind; if the 13 delivers amazingly strong performance your probably under propped and over revving.
If the prop seems adequate you may be in the ball park,if it seems sluggish you may be over propped and lugging the motor.
If over revving you can just reduce the throttle if lugging you shouldn't operate the motor extensively.
This is all assuming the motor is healthy, and the setup correct.Basically we are doing Russian Roulette with a fully loaded gun.
We need at the very least a lightly loaded test with the gear ratio, prop size and carefully done wot gps speed.Ideally we need prop size the gear ratio and a wot rpm and gps.
speed. The gear ratio may be 2.33.Mariner info is a little more difficult to find.

 

[zachfarmall]

I ended up with a10.25x14 works great but now I'm switching to an 85hp evinrude.thanks for help sorry for not responding sooner I broke my phone.