BluewaterBill, my apologies to you and our fellow readers. The numbers I gave you originally were provided by my dealer upon their 1.0 hour test before delivery. Everything I did with the trim and jackplate wouldn't even touch 6000 RPM'S
I ran the boat last night. First of all, the 115 I was impressed with as far as how quiet and smooth it runs. Now, to "my" numbers:
It was very windy in Oklahoma yesterday so I did my best to find smooth water.
2017 115 HO
21 pitch Viper
The hole shot is honestly quite poor. Lots of bow rise.
5900 RPM's at 44-45 mph GPS
The boat runs flat as a pancake.
I don't think I can gain a lot of speed but, with good bow rise, I think I can gain a few mph and a little better ride. It feels like the bow is just plowing water.
Thank you for additional input in advance!
10-26-2016 09:31 - edited 10-26-2016 09:32
Furthering Bill's analysis regarding theroectical speed and slip there is still somthing very odd here.
With a gear ratio of 0.5, a prop pitch of 21, and a speed of 45 mph. With a 10% slip you should reach that speed at around 5000 RPMs. This would actually indicate an over-propped scenario.
The number you post suggest a 30% slip factor. Again, you need to find the RPM and trim where if you trim up or jack up you no longer gain speed. You could be conceiling an over-propped situation.
Are you trimming the engine all the way down for acceleration and trimming it out until the prop ventilates then back down a fraction for best top speed?
PROPELLAR PITCH # OF BLADES RPM HoleShot Speed @ WOT Bow Lift JackPlate Position
VIPER (stock) 21 3-Blade 5980 4.5 sec. 45.9 mph Poor 1" off bottom
POWERTECH 21 3-Blade 5660 4.0 sec. 43.6 mph Poor 1" off bottom
RAKER 20 3-Blade 6067 3.85 sec. 44.9 mph Poor 1" off bottom
RENEGADE 21 4-Blade 5958 3.85 sec. 45.4 mph Better 1" off bottom
RENEGADE 23 4-Blade 6053 4.5 sec. 43.3 mph Better 1" off bottom
Any further recommendations gentlemen? 22pitch 4 blade?
"Renegade". All props provided by a local prop shop that allows you to test. I'm curious about the Rogue and your thoughts.
Are these the old O M C built V-4 Renegades ? What are the part numbers on them ?
Did you check the gearcase ratios per the article link that I furnished ?
The prop calculator still comes up with excessive slippage on the props. Please have the dealer check the tach with his laptop diagnostic software.
Trim tabs may have held the bow down and that is why you did not get much lift .