Prop selection

[Stinger]

I am looking for some help on selecting the best prop for my boat. It is a 1985 seacraft cc with 1993 250 horse yamaha.
It currently has an aluminum 14.25x21 inch pitch prop on it.
I can run approx. 5100 rpm. I am unsure of the speed as the GPS is currently not working.Any info would be greatly appreciated. Some prop selection guides recommend a 15.25x 19 inch prop. Help..............

[Fr. Frank]

You could probably run a 17" pitch prop, and raise your rpms to 5500-5600. A stern-lifting prop is generally best with SeaCraft hulls.

PowerTech prop offers a free evaluation to learn which prop is best for your boat. Go Here.
I recommend sacrificing a little top speed for low end and maneuvering torque. My rule of thumb is you want to be able to hit the upper end of the maximum rpm range for your motor even when loaded out to max weight.

Thats being able to reach Max of Max at Max.

In other words, if your maximum rpm range is 5200-5800 rpms, you want to be able to reach 5800 rpms with your boat at maximum weight capacity. This gives you a torque and power reserve in case of heavy seas, or in case of emergency, and you need to be able to apply more raw power. Horsepower you can't use is wasted power, and you never want to need it, and not be able to access it.

Accessible torque at sea is like a gun: It's better to have it and not need it, than to need it and not have it.

Besides, you'll get much better acceleration and handling, at the sacrifice of 2-4 mph in top speed, and your engine won't strain nearly as much getting on plane and at cruise power settings.