1400 RPM loss from 13 to 15 pitch!!!

[Miked3]

I'd gps the boat to compare vessel view. That's just me.

I have nothing more to add so I'm going to tag out of this discussion.

Vessel view goes through the phone app via Bluetooth. I have vetted out the speed with the Waze app which is also vetted out to the speed on both my vehicles which are calibrated through two other separate software with obd2. The speed is accurate.

 

[Miked3]

You were barely tapping your rev limiter on the original prop- that is basically about as good as it gets prop wise for a rig like yours. That is exactly how I prop my boat, just cause it can hit rev limiter doesn't mean you have to leave it pegged there.

One of the issues maybe overlooking with these results and the slip/rpm numbers that don't make sense is you are assuming the props published pitch is what it actually is, on relatively inexpensive aluminum props. Before you drive yourself nuts maybe worth finding a prop shop who can validate if the listed pitch is accurate.

I was in a 3 day fishing tournament last weekend on Lake Winnipesaukee and swapped props each day. I put on roughly 15 plus miles per day. On the 13 pitch prop I had to manipulate the throttle and trim to stick around 6000rpm and had to keep adjusting as the water conditions changed...islands blocking wind, wakes of other boats etc... It can be done but it's super annoying and having to constantly monitor takes away from actually enjoying the ride on a big lake with gorgeous views as you are trying to get from point A to point B. Based on all my numbers which I am 100% confident are accurate and my conversations with "experts" a 13.5-13.7 pitch would put me where needed. Both "experts" were not that surprised on the RPM gaps and have seen it several times before. If I had a prop shop that could check and manipulate the props I have relatively close I would have already gone that route. There is one last affordable stock prop that may split the difference but unfortunately itsa 4 blade again just a smaller diameter. I can return it so it's on its way. If that doesn't work I will look for a shop to send a prop to.

I really don't think there is any other variable missing or off and neither does the Lund dealer nor the custom prop shop. I think that the "experts" in this thread have just been spoiled with falling into perfect performance alignment on their rigs.

 

[QBhoy]

Something definitely isn’t making sense with that. Anyway. If you aren’t bothered. That’s fine, I suppose.

 

[Miked3]

Something definitely isn’t making sense with that. Anyway. If you aren’t bothered. That’s fine, I suppose.

The Lund dealer called me yesterday and told me to move the motor up two more holes which will be the last holes. Probably a manual 4" Jack plate would be ideal but unfortunately I don't have enough time to get it in, installed and tested before another week long trip on a big lake. So I am moving the motor up tomorrow and see what happens with the 14 pitch solas 3 blade and then mid week I will have that 4 blade to test.

 

[ejnichol]

What diameter are the Solas Amita 3 props your testing?

 

[Miked3]

What diameter are the Solas Amita 3 props your testing?

13.5" for 14 pitch, 13.75" for 13 pitch

 

[Miked3]

Ok so motor is now on the bottom holes, so all the way up. The anti-ventilation plate is now about 1.5-2" above the bottom of the hull. Flat water and just myself in the boat this morning gave me 31.5mph@5650RPM with the 14 pitch solas 3 blade. So I am now at least in the "safety zone" but with another full size guy it will probably drop a bit and hover around the minimum. The Solas smaller diameter 13 pitch 4 blade should arrive today and if early enough I will take the wife and test it out. I have a feeling this will be the one with the motor this high to put me where I need to be.

 

[Miked3]

30.5mph@5950rpm with the small diameter Solas 4 blade 13 pitch, the transducer doesn't care for the extra turbulence though but looks like this is the best prop for my setup. A jackplate should take care of the transducer issue but Im nervous about the extra transom torque on a non replaced 2014 transom.

Hopefully this thread will help someone else with similar issues in the future.