prop survey

[whatknot]

Here's tested props. Didn't have a 17 to test....

1985 Wellcraft v20 Fisherman CC
Closed Transom with Stainless Marine Bracket
Yamaha F150

Fuel topped off at 60 Gallons
2 batteries (unfortunately in the stern)
Full 20 gallon in deck livewell (unfortunately in the stern)
Boat is a tad bit *** heavy....

Prop RPM MPH GPH

Mercury Vengeance
14.5 x 15 -5700- 36 - 14.2
Cruise - 4260 - 24.4 -8.7
4.5 seconds to plane


Yami 3 blade SS Black (old)
13.5 x 19- 5600 - 36.2 -16
Cruise - 3800 - 25.4 - 10
6 seconds to plane

Spoke with Power tech dude. He recommended a OFS3R15 3 blade 15 1/4 x 15

or a OFS4R14P (15 1/4 x 14) 4 blade.

Anyone running these dimensions for a prop and what do you think?

Thanks

i have a 85' c.c. repowered with a 99' 225 efi merc... this has been a project just finally putting on the pieces together. first run with a 13"x21p mirage wot 5100rpm 53.5mph----4000rpm 40 mph......2nd run 13"x17 quicksilver 5800 rpm 50.5 mph----4000 33.5mph.... waiting till this weekend to try a buddies 19p wheel hope thats where i need to be

[Genie Aye]

200HO E-tec

15x19 Rebel SS

5400 RPM

Light load--53.4 gps

average load--52.0 GPS

Cruise at 35mph at 3750rpm


Thinking about a 4 blade to create some stern lift with the heavier motor.

[tnltracy]

I have a 13-3/4 x 15 aluminum currently. Last year I was getting around 24MPH at 5500 RPM by GPS. Start of the year I was showing around 29MPH, but her butt got a bit dirty over the summer

At WOT, the motor would over rev well over 6k RPM, so I've been shopping for a new prop this year. I just picked up a used 13-1/4 x 17 that I'm hoping will take RPM's down a tad and give me a few more MPH's. Will report once the boat gets into the water

[kman104501]

I have a 19 pitch ss, not sure what dia, 225 Evinrude, WOT 50MPH after being in the water for 1/2 a season. Always wondered if it would pay to go slightly larger....

[Genie Aye]

Originally Posted by kman104501

I have a 19 pitch ss, not sure what dia, 225 Evinrude, WOT 50MPH after being in the water for 1/2 a season. Always wondered if it would pay to go slightly larger....

At WOT with a average load--what rpm are you at?

Rpm will tell you if you are prop'd right or not--you do not want to over prop for sure.

[kman104501]

Originally Posted by Genie Aye

At WOT with a average load--what rpm are you at?

Rpm will tell you if you are prop'd right or not--you do not want to over prop for sure.

I am able to get to 5600RPM without a problem with 3 people, full tank of fuel and fishing gear (of course).

[Destroyer]

Originally Posted by tnltracy

I have a 13-3/4 x 15 aluminum currently. Last year I was getting around 24MPH at 5500 RPM by GPS. Start of the year I was showing around 29MPH, but her butt got a bit dirty over the summer

At WOT, the motor would over rev well over 6k RPM, so I've been shopping for a new prop this year. I just picked up a used 13-1/4 x 17 that I'm hoping will take RPM's down a tad and give me a few more MPH's. Will report once the boat gets into the water

Pitch is the theoretical distance that a propeller will move through the water in one revolution. (not counting slippage). So a 21p propeller will move 21" through the water in one revolution...a 15p will move 15" etc etc. As a general rule of thumb, expect to see a 300-400 RPM DECREASE for every 2 inches of pitch that you INCREASE your prop. (Propeller pitch is normally changed by a factor of 2"....13,15,17,19 etc.) Find out what the recommended WOT RPM's are from your motor's manual, and then size your prop until you arrive close to it. If you are into watersports like tubing or sking you'll want to go down one size in pitch, which will result in better pulling power and faster hole shots but less top end speed. If you're into going places in a hurry you'll want to go up one size in pitch which will result in a faster top end but less pulling power and longer time to get up on plane. In all cases stay in the recommended RPM range.. over-revving or lugging your motor will result in a greatly shortened motor life.