More speed wanted

[Alexwalms]

27ft rib with 300 Suzuki- current prop 15 1/4x 22p

On my own I’m hitting 6300rpm @48knts and sometime hitting the limiter with a bit of trim, is it worth getting a higher pitch prop or should I look at having the one I have altered to a higher pitch or adding cup?
Ideally want a bit more too speed, recommended wot range is 5800-6200rpm for the engine

[gtflash]

I’ve always paid for new props rather than tweaking them. But it’s expensive. its easier to sell a standard prop.

What’s your engine height like? Do you ventilate or cavitate in corners or rough weather? Can you get on the plane easily in current setup?

What prop is on the boat. I presume it’s a reputable 4 blader?

[lakelandterrier]

Why do you want travel at more than 48kts?

[Alexwalms]

Yes it’s all set up fine with regards to engine height etc, it’s a 4 blade solas prop, I have found a Suzuki 24p prop but not sure if that’ll put me too low in the Rev range.

[Roflhat]

I'd definitely try the 24p, being a 3 blade it will have less drag so you shouldn't lose too much rpm. If you still want some tweaking after that go to Steel Developments or Streamlined Propeller Repairs

[willk]

Originally Posted by lakelandterrier

Why do you want travel at more than 48kts?

Seriously, you don't know?

So he'll be able to point at it and truthfully say: "50 knot boat, that is!"

Personally I'd leave it alone, rigged for some peeps and gear, do a run down tide and down wind, photograph the plotter and call it a day.

[rou7]

Originally Posted by willk

Seriously, you don't know?

So he'll be able to point at it and truthfully say: "50 knot boat, that is!"

Personally I'd leave it alone, rigged for some peeps and gear, do a run down tide and down wind, photograph the plotter and call it a day.

Xaxaxaxaxaxxaxaxaxa good idea that

[gtflash]

Originally Posted by Alexwalms

Yes it’s all set up fine with regards to engine height etc, it’s a 4 blade solas prop, I have found a Suzuki 24p prop but not sure if that’ll put me too low in the Rev range.

Engine Height is where the real tuning is. Most manufacturers hang the engine where they hung them all without any height tuning (too low). It is in my opinion the first and most important setting to get right.

I have ended up with a rev4 prop on last two boats, one a 50mph boat and another 70mph. Great amount of grip, lift and top speed. It’s as fast as a laser2 and as grippy as a bravo, less prop torque than a trophy and more grippy than a high5 (yes I like Mercury props). However if you ever change engine height it will impact size of prop.

How high is prop centre in relation to keel?