Choosing a prop for higher altitude boating

[ToddWY]

Wondering if anyone has experience selecting props at higher elevations?  I hit 31 MPH at 5900 RPM WOT. Full fuel tank and two adults so a pretty light load.  With a heavy load (4 adults, 2 teens, 2 kids, 2 coolers, more gear than needed) and Bimini up I don't lose much, maybe 1-2 MPH.  I also boat at a little higher altitude, about 4500 ft.  From my limited research I think that means I need to drop about two pitch sizes from what would be optimum at sea level.  



Boat Model --------- 22' SSRCXP
Model Year --------- 2017
Tube Option -------- SPS, strakes on center tube and interior of outer tubes 
Power Option ------- Evinrude ETEC 150 (Full Throttle Operating range 5300 to 6000 RPM)
Prop Specs --------- 3 Blade Stainless - 15 5/8 x 11p


I hit 31 MPH at 5900 RPM WOT. Full fuel tank two adults so a pretty light load.  With a heavy load (4 adults, 2 teens, 2 kids, 2 coolers, more gear than needed) and Bimini up I don't lose much, maybe 1-2 MPH.  I also boat at a little higher altitude, about 4500 ft.  From my limited research I think that means I need to drop about two pitch sizes from what would be optimum at sea level.  


I'm wondering if going to a 13 pitch prop would give me a little more top end, if there's something else I should check, or if that looks dialed in already?  Honestly I don't need more speed for enjoyment, but if a small tweak can improve the performance I'd be silly not to try, right.
 

 

[adkboater]

What model evinrude prop do you have, different models will get you different result based on their design. I run the rebel series and love it, the viper might get you a few mph on top but stinks for tubing, etc. plus my fuel consumption improved with the Rebel. Is an G2 or G1? Is it an HO motor as that would they another few curves in there.!  

 

[ToddWY]

What model evinrude prop do you have, different models will get you different result based on their design. I run the rebel series and love it, the viper might get you a few mph on top but stinks for tubing, etc. plus my fuel consumption improved with the Rebel. Is an G2 or G1? Is it an HO motor as that would they another few curves in there.!  

The prop isn't anything fancy, SSP TBX (Part #763959).  Not much info that I can find, seems to be their generic base line prop.  Engine is not an H.O. or G2, I don't have the model # in front of me, but it's a 2.6L with 25" shaft.


What did you have before the Rebel?  That looks like a good prop for my needs as well.

 

[adkboater]

I started with a 16 pitch Viper series prop and was satisfied with the top end performance but once we started to tube and actually run the boat at less than full throttle( I eventually learned that the lever has adjustment not just to the stop!  ) I found it blowing out easily with a few people on the tube. I have tried many props and have come back to my 15 pitch Rebel prop every time. It's great all around, maybe a couple mph slower on top but I'll give that up anytime for being awesome everywhere else. You have the same motor I do in just tuned in at 150hp. I wouldn't have any issue pushing towards a Rebel but I think they only make it down to 15 pitch. If I can find a few minutes tomorrow I'll do some digging and see if I can come up with some part numbers. Do you have a dealer that will let you try a few props?? It's get to be pretty expensive with trial and error!

 

[ToddWY]

Thanks for the info.  I did look into the Evinrude props and you're correct, the Rebel only goes down to a 15 pitch.  Not a lot available in a 13 pitch so I might not have a lot of choices.  I'm guessing a 15 pitch would drop my RPMs to much to be usable.  I'll see if my dealer will let me try a couple props, but they're 2.5 hour drive away so not real easy.


On a side note I lived in Philly for 10+ years and spent a fair amount of time up in Lansdale with friends.  Liked your area and was thinking about moving that direction before I came back out west.

 

[adkboater]

I haven't been able to catch a breath here lately to do any looking but my 24' boat with 200hp and 15 pitch prop runs 5350rpm which is at the peak horsepower on that engine. I wouldn't be surprised if the 15 pitch wouldn't work on the 22' boat. 


Were just 10 minutes north of Lansdale, love the area, grew up here but no lake in site unless I do like Semp and stick to 20hp. Maybe I could just scratch a zero off and nobody would notice!