Prop selection 20' MA 175 Mariner

[Blue_Heron]

Originally Posted by CHANCE1234

Your planing speed has a lot to do with how much your 175 weighs. Theses boats are designed for engines in the 300lb range...

X2.

Minimum planing speed has more to do with the boat's weight and center of gravity than it does with your prop, but correct propping will definitely help. Try taking your largest friend for a boat ride and asking him/her to sit on the forward casting deck while you reduce throttle and trim the motor down. You'll probably find the minimum planing speed much improved.

Based on WOT engine RPM, your boat sounds like it's propped ok, but I would have expected more speed and less rpm with that combo. So the prop may be long on pitch and short on blade area, which might hurt it's performance at lower speeds. A Mirage 17 is a pretty good choice for all around performance and they can be had pretty cheap on ebay if you're patient. When I put one on my 20 with a 200 Merc, it improved low speed and cruise performance without losing a lot in top end.
Dave

[gofastsandman]

Originally Posted by Blue_Heron

X2.

Minimum planing speed has more to do with the boat's weight and center of gravity than it does with your prop, but correct propping will definitely help. Try taking your largest friend for a boat ride and asking him/her to sit on the forward casting deck while you reduce throttle and trim the motor down. You'll probably find the minimum planing speed much improved.

Based on WOT engine RPM, your boat sounds like it's propped ok, but I would have expected more speed and less rpm with that combo. So the prop may be long on pitch and short on blade area, which might hurt it's performance at lower speeds. A Mirage 17 is a pretty good choice for all around performance and they can be had pretty cheap on ebay if you're patient. When I put one on my 20 with a 200 Merc, it improved low speed and cruise performance without losing a lot in top end.
Dave

I think I`m up to 6 or 7 props now.

I think you will be blown away when you find the right one for your boat.
Every boat is set up differently.