finding the right prop

[GodsReel]

thanks guys, i guess i think i will try a 4 blade when i have the cash, i would like to have a slower plane speed for certain days , got caught in ches. bay coming back from drum fishing in a stacked up 4-5 ft NE 20-25 and needed a slower plane speed . thanks for all the help.

[shine]

Originally Posted by GodsReel

thanks guys, i guess i think i will try a 4 blade when i have the cash, i would like to have a slower plane speed for certain days , got caught in ches. bay coming back from drum fishing in a stacked up 4-5 ft NE 20-25 and needed a slower plane speed . thanks for all the help.

or a bigger boat

I had a chance to run the new 17 pitch 15.25" 3 blade in the river (pretty flat water) and there is still cavitation unless the motor trimmed almost all the way down.

I was getting some good numbers though: One tank of fuel (55 gallons), three adults and a child on board, I ran 27 mph at 3900-4000 29/30mph at 4200-4300. Hooking up the fuel flow this week so we will see where the best fuel burn comes in at.

I believe the next step will be to lower the motor a notch

[Fr. Frank]

Pay close attention to the mounting height of your motor, If you're still ventilating (It is NOT "cavitating") at any motor trim angle other than pretty well trimmed down, I would suspect one of three causes:

1: motor mounted too high (this would also explain slow time to plane with accompanying cavitation upon hard acceleration from a standstill)
2. insufficient cupping on the trailing edge of the propeller blades OR full cupping not extending to the middle of the blade tips
3. A wake obstruction on the hull ahead of the propeller/lower unit such as a through-hull fitting or transducer.

Cavitation is air bubbles forming on the trailing side of the propeller that is caused by pressure differential, and results in reduced "bite" and reduced thrust.

Ventilation is air bubbles being pulled down from the water's surface to the trailing edge of the propeller. The whole purpose of cupping a propeller is to minimize ventilation, and yet still allow a propeller to run right at the water's surface, minimizing drag and friction.