Prop removal questions...

Mark - of course you guys already talked about it!, I obviously need to pay more attention to this thread... So no issues on the clearance, increase of 3/4 inch of dia, only brings the tip 3/8 inch closer to the hull, so I guess not... Maybe I will give ACME a call and see if they can come to Green Lake and demo props - that might be a good idea. Then we could run, a 470, 422, 224, 1442 and at that point I would even try the 1458

Steve go back at bottom of last page I asked Tim about the 2068.

TRBenj wrote: Lewy, bummer on the prop. The 2068 is the cupped 470 IIRC, and would make it turn pretty similar revs to the 422. I am not a fan of adding that much cup to the prop (prefer to keep it at .105 or below). I think adding that much cup just makes the prop less efficient. A few of us have added cup to props and while its effective at dialing in RPM to the desired level, it usually does not come along with increased speed as it should. More pitch is really the ticket for these situations.

Steve see above post about 1442 even though it is a larger diameter 13.25" compared to 12.5" I was able to turn it 5030rpm better than both the 422 and original OJ legend it also produced my best top speed and this was all in a boat with 5 people and gear with low fuel.

Looking forward to back to back testing it against my yet again repaired 422.

Kurt the 224 would be worth a try especially at reducing rpm at footing speeds.

Kurt, the 224 would be interesting to try as its pretty close in size to the proven 422. Skip the 668, it's the extra-cup version of he 422 (meant for 6.0l boats) and would be taller than ideal.

Finally tried a WOT run with the 1442 today. The prop has felt good since installed plenty of bite on hole shot and reasonable rpms at skiing speeds.

With 5 people in the boat 36 mph is almost 4000rpm with skier behind boat.

Top speed was 43.1 @ 5030rpm with 5 people and plenty of gear in the boat.

Should have my repaired 422 back this week. Not sure if it will go straight back on now.

kapla wrote: Details on how you chewed that prop! Boomer

We decided to go to a different dam that we had not been skiing on for a few years. It was a late decision on Sunday afternoon as the conditions were perfect and this dam is the closest but requires ideal conditions to get good water. It was down to about 80% capacity which we had no experience at either. I was actually skiing when the boat stopped, quickly realised what had happened when the water was just over knee deep as I dropped back into the water.

TRBenj wrote: What were your RPM's with the 422?

Tim, I was getting 4940 WOT on the 422. I had always wanted to try the 1442. I am leaning to ordering one and if it increases the RPM to much thinking of adding a bit of cup as it only has 0.090 standard.

The 422 may be repairable so I do not want to end up with 2 of them. Although I think that the 422 may be the best prop for our application. A fresh untouched 422 may even been better than my 422 that I have massaged a few times. I did have it repaired last year by a very reputable company before doing my prop testing.

Details on how you chewed that prop! Boomer

Tim how would a ACME 2068 perform compared to the 422?
Would the extra cup (0.150) reduce WOT rpm's compared to the 470 with (0.105). Have you done any testing with this prop?

The reason I ask is that I damaged my 422 yesterday it may be repairable but I was thinking of ordering a new prop. I would have ordered a 1442 previously but you mentioned it would turn higher rpms just like the 470.

Ok, so next test will include some more jockeying of the ballast (putting it in the trunk), I will use the digital speedo instead of the dial, and I will hook up a temporary digital tach to verify operation. I probably will for go any additional video. I think the video taken so far demonstrates the water breaking point on the hull, and has established that I am reading the gauges correctly (HA!). IO got a get some time to fly down to DBQ, take Valant for his airplane ride and pick up his 1442 for testing... Dang work gets in the way!

I think your tach is lying to you. A 422 will run closer to 1:1 on a lighter Ski Nautique at skiing speeds. It will still overturn by a good margin at WOT (by nearly 400rpm. ie, 46mph @ 5000 rpm). I dont buy that a larger/heavier Sport is only turning that prop 4450rpm at 44mph. Its probably closer to 4800-4900. You'd want to prop it to run 4800-5000 anyways.

Thats the right place for them (unless you can get them further back like in the trunk or on the platform). It doesnt sound like you sped up at all? Does your GPS only read in 1mph increments?

Where did you have the fatsacs?

skutsch wrote: I have seen 'Dyne's riding like the bass boat above. Mike, thanks for the info on the prop, What I would like to do is plan a day to come down and pick it up in the plane (and get you your airplane ride). Then I would run it up here on a couple of boats, collect data and then bring it back. Looks like I am going to have to get working on the schedule. Will that work?

YES!!!

Let me know what kind of dates you're looking for and I'll let you know what's going on. I know we're out of town...June 9th I think it is. But yea, let me know.

mdvalant wrote: Wow there is not much of that crush in the water

Its bouncing due to the water conditions and weight in the back. Just a well timed photo. It was to show that a single snapshot can be very misleading.

Agreed- 40mph is all you need to barefoot. 43+ with a footer is only needed if youre a BIG boy or doing 1-foot stuff.

Chris, that picture is worthless (as far as judging running attitude) because of the water conditions. Cool pic though! Similarly, the Crush doesnt normally run *quite* this bow-high.



Mark, youre absolutely right- a 12.5x15.5 or 12.5x16 modern CNC 3-blade would be great to try, as it might give you close to another mph. Too bad no such prop exists!

I would absolutely say that yes, the up side of having a "slow" hull is that because the nose is more planted, the slalom wake is improved. I think it helps the barefoot table a bit as well, as the turbulence behind my '90 is much more manageable than it was behind our former '92.

My contribution....Thanks again Mr. Morfoot for the pic.

Our windshield is back another 9" so I'm guessing it's worth at least another MPH or 2?