Dinged up a prop

[MTribe08]

Hi guys, Had my first screw up...nicked the prop on the ramp loading. Bummer, but it happens. Its not worth fixing and I have a backup, so I'd like some feedback as to what I should get next. I think something slightly different might be better for the type of boating I do most.

Here is what I currently have.

-1995 Monterey Montura 210 3000lbs dry, probably 3700-4000lbs loaded on a normal boating day. 20' 10" long
- 1995 5.7L 4bbl carb. 240hp I believe.
- 1995 Alpha one Gen 2 sterndrive
-3 blade 14x21 aluminum prop
-top RPM for the motor is 4800 I believe, but I've never been there.

-On the speedo I'm at about 43mph at 4100
-I rarely push the boat to that range, I do the majority of my crusing at 3000 RPM/30-32mph on the speedo. Top speed is not a major concern.
-I do believe I"m experiencing some "cavitation??" at the higher speeds when I trim up..the boat will climb RPM's but not gain speed, sometimes fall..that happens once I get up in the 4000rpm range.

** Performance issue you are trying to correct.
I would like to find a prop that will hold low end speed well. We do alot of Wakeboarding in the 19-21mph range. Eliminating the high end speed caviation would be nice too

-I did some research before posting this and if I'm reading correctly, a 4 blade prop might be better for the type of boating I do?? Not sure on the pitch however.
-The 3 blade 14x21 that I have, does fine pulling us out of the water..but an easier hole shot that really grabs and holds would be really nice.

Thanks in advance for your help,
David

 

[truckermatt]

Re: Dinged up a prop

i would get either a 4 blade alum... or the mercury High Five Stainless five blade prop...

Both will give better holeshot.

 

[steelespike]

Re: Dinged up a prop

If your sure the motor is in excellent tune and the throttle opens all the way
you need to drop in pitch.Its normal to drop an inch when going tro a 4 blade
you definately need to raise your rpm so I would think a 18 or 19" pitch would help.
A vast improvement in hole shot and no more venting problems. I've heard the solas amita 4 blade suggested.

 

[MTribe08]

Re: Dinged up a prop

If your sure the motor is in excellent tune and the throttle opens all the way
you need to drop in pitch.Its normal to drop an inch when going tro a 4 blade
you definately need to raise your rpm so I would think a 18 or 19" pitch would help.
A vast improvement in hole shot and no more venting problems. I've heard the solas amita 4 blade suggested.

Thank you guys.."venting" was the word I was looking for. I should have added that I have more throttle left when I get to the 4000-4200 range..but I see no use in going higher because of the venting so I back off.

 

[MTribe08]

Re: Dinged up a prop

Is it fair to say, that if I go from a 21" 3 blade to a 19" 4 blade, its basically the same if I were to go from a 21" 3 blade to a 20" 3 blade?

I keep reading that you'll gain roughly 200-400 RPM every inch you go down. But i don't know how that translates when you go from 3 blade to 4. All Aluminum.

Thanks

 

[steelespike]

Re: Dinged up a prop

Keep in mind these figures are approximate and a prop change
when going to same brand same style can be somewhat of a gamble.
Anything more really puts more unknowns into the equation.I've seen gong to less pitch end up losing rpm.But yes you could say dropping 2" when going to a 4 blade could be like dropping one in a 3 to 3.

 

[MTribe08]

Re: Dinged up a prop

Ok, thanks