www.iFourWinns.com

Hi everyone,
It has been a while since I last posted. I am currently running a 3 blade, Vengeance 19p ss prop on my H180 3.0. This prop generally serves me well and I realise that I can get only so much performance from this boat/motor set up. Anyway I use the boat for mainly tow sports. The concern I have is that when my friends and I slalom ski we want to go a little faster and now the engine rpm is around 4300 to 4400. The boat will currently hit 4800 no probs at wot when pushed.
Now I would like to drop the engine rpm when skiing by about 100 to 200 rpm for the sake of the engine, to around 4000 to 4200 rpm.
I have read a fair bit about the Enertia and the Enertia Eco props, compared to my current Vengeance prop. The Vengence seems to be more general purpose, while the Enertia props seem to be better designed for the purpose of tow sports.
Enertia Props
1) thinner blades
2) smaller diameter
3) more efficient design
4) they have vent holes to allow the engine to "spin up quicker to improve hole shot"
5) X7 alloy (7 times stronger)

Current Vengence prop
1) slightly larger diameter
2) thicker blades
3) no vent holes
4) more general purpose

I am considering going to a 3 blade 20p Enertia or Enertia Eco to reduce the rpm when slalom skiing .
While I am confident that I will reduce the rpm by around 100 to 200 rpm with the Enertia 20p
My concern is, will my hole shot be "dramatically" reduced if I go with this pitch on the Enertia.
My understanding is no or not by much, allowing for the fact that the Enertia props are:
1) slightly smaller in diameter
2) they have thinner blades
3) they have the vent system
4) they have a more efficient design
I realise that a test drive would be the ideal but very inconvenient (300 mile/500 km) round trip to a shop that will let me test drive one.
Anyway I am interested in what everyone thinks, especially if you have used one.

Regards,

Ardy

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Ardy
Adelaide South Australia
Red H180 3.0 Merc

Sounds like the prop you have now is ideal for what you are doing. You need those rpm's for the hole shot.
You are not hurting the engine at 4400 rpms. And 200 rpms is not going to mean anything for engine longevity.
More important is keep the oil changed (with good oil, I personally use royal purple marine) and keep a watch on your temp gauge.

I would not spend the money.

One other solution, if they are willing to let you try it in person, will they not allow you to purchase, try, return as long as you don't damage it?

But again, I would not spend the money.

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The Dance II
2007 278 Vista
6.2L Mercruiser

While I do not have experience with those particular props, my understanding is that the vent hole does provide better hole shot by allowing the engine to get to a higher rpm (and therefore higher Horsepower) during the initial hole shot, with virtually no penalty on the top end.

So my guess is the same as yours...that your hole shot (pulling a slalom skier) would not be reduced, or not by much.

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"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings

Hi everyone, I have a follow up to my original post. I rang Hodge Marine here in Adelaide and spoke to Craig who was very helpful, when I explained what I was hoping to achieve. The long and short of it all was, they had an entertia prop that was a 19 inch pitch that had done about an hours work in new condition that I could try out. The deal was I paid the agreed price, they put the money in an envelope, if I damage it in any way, I've bought it. Other wise I could return it and get a full refund if it wasn't suitable. It was recommended to do several tests with a stopwatch, each test I repeated three times to get an average time, so here are my findings.
All tests were with the trim all the way in, unless otherwise stated
1) In gear idling to 20 mph was .25 seconds quicker with the entertia prop by the speedo
2) 20mph to 30 mph by the speedo was .53 seconds quicker with the entertia prop
3) 20 mph by the gps. Vengeance 19 pitch 3150 rpm, Enertia19 pitch 3100 rpm
4)30 mph by the gps. Vengeance 4200rpm, Enertia 4100 rpm
5)4400 rpm and trimmed to the first big line on the trim guage, Vengeance 33 mph(gps),Enertia 34mph (gps)
WOT by the speedo trimmed all the way out 5000 rpm 44mph with the Enertia prop. My previous top speed with the same rpm using the Vengeance prop was 43 mph by the speedo.
To sum up in the real world the the Enertia prop feels like it is gripping better and feels stronger.
When slalom skiing at my preferred speed the engine is now spinning at approximately 100 to 150 rpm less than before. The Enertia prop is doing what I had hoped for, so yep I've bought a new prop!
Hope my findings are helpful to someone here.

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Ardy
Adelaide South Australia
Red H180 3.0 Merc