Replacing Vengeance SS, need less RPMs

[longshanks]

After trying a number of props, I've found a Quiksilver / Mercury Vengeance SS, to be the best performing prop for my setup. However, WoT RPMs are too high

- Mercury 50HP 4-stroke EFI, tiller handle. Recommend WoT RPMs 5500-6000

- Quiksilver SS 11 5/8 by 11 Pitch prop

- GREAT holeshot, 31 mph top end, but easily reaches 6000RPM, and alarm goes off at 6200, and motor feels as if it may wind out a little further.

- heavy aluminum boat with 6 degree bottom, 15', about 1300lbs w/ motor. Motor is raised to maximum height possible.

I plan on keeping this prop, because it performs so well with a load, and it could be used for wakeboarding/skiing. But I'd like something that could be used for cruising, that won't over-rev the motor. Any suggestions on what I should look for?

I'm thinking that a 12-pitch should do the trick. Will a turning point hustler aluminum prop perform as well as my SS prop, in terms of speed and RPMs? Or should I stick with stainless?

cheers

Shane

 

[longshanks]

Re: Replacing Vengeance SS, need less RPMs

after reading another post 'safe RPM range', I've concluded that by using an 11 pitch vengeance SS prop on my boat, I'm propped to hit the RPM limiter, in 'ideal' conditions. It gives me about 50km/h @ 6000-6300 RPMs. Speed doesn't seem to vary much, between 6000 and 6300 RPMs, nor does it vary with different loads. Holeshot is very strong with this prop, but I'd be happy if I could get some more top end speed out of my setup.

I am interested in hearing your thoughts about whether or not I'd be able to get much more speed out of this setup, by going to a different SS prop, such as a stilletto or something, in a 12 pitch. I will be keeping the original prop, because it performs very well with holeshot, and load-carrying. But I'm wondering if I

ideas?

 

[Esox]

Re: Replacing Vengeance SS, need less RPMs

If speed is what your after your going to want to stick with a SS prop. Your best bet is to find a place that will let you try out some different props. A 12p by manufacturer a most likely will not give the same numbers as a 12p by manufacturer b.

Motor is raised to maximum height possible.

Do you have a water pressure gauge? I would be concerned with the alarm going off at 6200. What is the alarm at 6200 indicating?

 

[stevens]

Re: Replacing Vengeance SS, need less RPMs

You'll probably gain about 2-3 mph top end speed by going to a Stiletto, Turbo or Ballistic prop. All of these have more cupping (whereas the Vengeance has very little) and so should grab on better to the water and make more out of those high RPMs. For the same reason, I'd avoid an aluminum prop, which cannot be made as cupped as a steel prop.

Since you so easily get to 6300, and aim to hit just below 6000, a cupped SS 12P or perhaps even 13P (depending the make/design) seems about right. There's a sale on Turbo/Stiletto over at boatownersworld.com these days, plus propline.com is a good place to get the Ballistic.

 

[longshanks]

Re: Replacing Vengeance SS, need less RPMs

I think the limter is set to go off at 6150 or something? Not sure on this. I only have had the steady-tone alarm go off one time, and based on my memory, the RPMs were at 6300 or so... If I keep the throttle held wide open, I can easily exceed 6000 RPMs. For this reason, I am thinking I might be able to grab some more speed with a higher pitch, better-designed SS prop.

I do not have a water pressure guage. The motor has a smartcraft guage, and my reasoning is that if the motor continues to pump water (it does) and motor head temperature doesn't trigger the alarm (it doesn't), then I'm probably ok. I have been watching the operating temperature on the smartcraft guage, and while it is running, it doesn't exceed 120 degrees. At this operating temperature, I am assuming that water pressure must be adequate...

 

[longshanks]

Re: Replacing Vengeance SS, need less RPMs

one more question.

Should I go with a turbo hot shot, a stilletto triad, or a ballistic?

tiller drive, aluminum boat with a small tunnel.

 

[stevens]

Re: Replacing Vengeance SS, need less RPMs

Your call - they're all good props for speed.