Prop Selection

[dihrdskir]

Calling anyone who can help with some ideas about prop selection. I'm doing too much slalom and cruising with the VTX and am looking at knocking 500 to 750 RPM off the top end without giving away too much down low. The VTX is fitted with the 340 and currently spinning an acme 13.5 x 16.5. I'm considering going up an inch to 17.5 pitch. Any thoughts??

[mibarefooter]

Calling anyone who can help with some ideas about prop selection. I'm doing too much slalom and cruising with the VTX and am looking at knocking 500 to 750 RPM off the top end without giving away too much down low. The VTX is fitted with the 340 and currently spinning an acme 13.5 x 16.5. I'm considering going up an inch to 17.5 pitch. Any thoughts??

You could call ACME or OJ and they would beable to tell you the exact prop that will work best for you and your situation.

[Coach Mike]

Lots of discussion on props if you do search. There a group but for paying members right now as well so you can definitely get a good deal if you decide soon. I just got the OJ 475 on advice from the forum and others that have my set-up.

[dihrdskir]

Lots of discussion on props if you do search. There a group but for paying members right now as well so you can definitely get a good deal if you decide soon. I just got the OJ 475 on advice from the forum and others that have my set-up.

Thanks Coach. What's your set up? What are the dia x pitch of the 475. Sounds like you got good advice.

[dihrdskir]

Calling anyone who can help with some ideas about prop selection. I'm doing too much slalom and cruising with the VTX and am looking at knocking 500 to 750 RPM off the top end without giving away too much down low. The VTX is fitted with the 340 and currently spinning an acme 13.5 x 16.5. I'm considering going up an inch to 17.5 pitch. Any thoughts??

You could call ACME or OJ and they would beable to tell you the exact prop that will work best for you and your situation.

Thanks mibarefooter. I'm hoping to luck onto someone who's tried both with a similar set up to get their thoughts.

[DONTW8]

For each 2" change in pitch expect about a 350 to 400 rpm change.

Another way to do it: Lets say you have a 19" pitch and you change to a 17" pitch. Assuming the same slippage whatever speed you are going at 3400 rpm now with the 19" pitch will require 3800 rpm with a 17" pitch.

I would be careful about increasing pitch too much. If you are skiing and trying to hold 32 mph dead on it is much easier to keep the speed exact with the lower (17") prop than the higher (19") prop.

I'm not so sure I would change from your acme 16.5" pitch prop for skiing. You'll lose some ability for holding perfect speed.

For cruising you can go up in pitch maybe 2" maximum and be careful about dropping too much max rpm at WOTB (wide open throttle, baby).

[OTN]

Hey all,

Quick question about high-altitude props. I currently live in Missouri but am looking to buy a spare prop. I head to Lake Powell once a year for an epic houseboat trip and could use a high-altitude prop for the spare. Any luck with these? Will it make a difference?

Thanks!

Ryan

[Bobby Light]

Lots of discussion on props if you do search. There a group but for paying members right now as well so you can definitely get a good deal if you decide soon. I just got the OJ 475 on advice from the forum and others that have my set-up.

Mike that is a sweet looking boat. I really like grey's on Malibu's.

[D-GOOSE]

Lots of discussion on props if you do search. There a group but for paying members right now as well so you can definitely get a good deal if you decide soon. I just got the OJ 475 on advice from the forum and others that have my set-up.

Thanks Coach. What's your set up? What are the dia x pitch of the 475. Sounds like you got good advice.

Di let me get this right so that I could help. You ski alot and would like to keep your current speed but drop your RPM's right? If so the 475 is the wrong prop for you. It would give a better hole shot and have less top end or same speed with more RPM's.

I could not find your prop specs you gave and was hoping you could re check them for me. Below is what I think you may have.

Part #:acme537 Acme - Dia: 13 1/2, Cup: .105

Pitch: 16 Blades: 4 Shaft: 1 1/8 Rotation: LH

I would also call ACME and OJ to see what prop they feel would be best for you. Please make sure you have as much data for them when you call.

[DONTW8]

Re: high altitude

Lake Powell is 3700 feet above sea level.

You do lose signifigant power especially if you are used to your boat at 1000' ASL.

I run a different prop for the high lakes. We often go to Crescent Lake, Cultus Lake and these are at 4800' ASL.

I drop 2" in pitch for these lakes.

On our big trip each year I tend to carry more gear on board such as an extra anchor, wetsuits, fenders, and so forth. And the boat has more people on board because we have 25 or so in camp. So for the ten day annual trip I use the lower pitch prop for that, also.

When we do our day trips to the course at Billy Chinook (el. 1945 ASL) I lighten up the boat so I can get by with the standard prop.

I live at 4100 ASL and Prineville Reservoir is about 3235' ASL also. You can tell the difference between Lake Billy Chinook versus Prineville versus Crescent. The Portland folks (100 ASL) complain about inadequate power at Prineville and really complain at Cultus.

I would buy my spare in a 1 or 2 " pitch drop for Lake Powell.

Edited May 1, 2009 by DONTW8