If you can hit 6200 like RiverRat here are the numbers: 6200 / 1.86 / 20.06 / .1 / 57 So it is 6200 rpm with a 20 prop for 57 mph if it can pull that much. jim
I just looked at the last picture showing the bottom. That looks like a pad v. If it is a pad v it is begging for a hydraulic jack plate and a surfacing prop at about 26 pitch or more and really stomp the inboards by a bunch. It would not pull well, but it would go!! When water skiing, you lower the engine back down and add a ski prop. Check with the designers, they should know. jim
Thank you Jim and Must Ski Friend's boat is a Stejcraft Pro Skier (Australian boat), very quick for a centremount. At 49mph the 17 would be running out of RPM and the footer and boat load wouldn't be the limiting factor???
Must Ski You are seeing about the same exact top end that I see with a 225 and a 19 pitch prop, but you're doing it with a longer, deeper, heavier boat. Makes me wonder what the differences are in my setup, aside from running a Merc. One difference might be gearing. Jim? Jim - my max RPM in the owner's manual shows 5750 and I think I do see something not too far from that at WOT.
You are both running on the rev limiter, so the speed is about the same. Your rev limiter is probably around 6000 + -. His drag is probably only a little more at speed. If the motors had props designed for top speed, you could probably run more pitch and out run him. jim
Dyne Greg, can I ask what you managed to pull with what pitch high five. I've tried a 23 on my 225Vmax and it doesn't look like I'll get the traction I'd hoped for on the big pulls. Holeshot is fierce. The motor is able to break it free, get right into the power band of about 250hp and still accelerate while all this is happening. It did pull three blokes dragging legs before I put the wedge on. I don't know what its limit is but I suspect from the amount of takeoff slip that 4 90kg blokes on normal slaloms draging a leg would be the limit. That is pretty good but it that HP could pull more if the prop got it to the water. My prop was second hand so maybe it isn't perfect though. I used to have a 150 Yamaha with a 21" high five and that was perfect on that boat. Medium vent plugs limited slip at low speeds to very drivable levels but still gave it enough to really sharpen the holeshot.
ghind, I have heard rumors that BRP is coming with a new gearcase for some of the big motors. All of the numbers I gave you were for 1.86 gear ratio. You should probably verify the gear ratio of your new motor before getting a prop. jim
I looked at the Mercury Bravo One specs. That thing is 15.25 in diameter with 4 blades. That is a bunch of blade area and will really load that motor in a pulling situation in 22 pitch. jim
