Prop Dilemma -- What to do?

[dgfrinell]

Hello all,

I apologize if this topic has been covered before, but I haven't been able to find what I'm looking for. So I'm hoping you all can deal with me for a bit and share some of your knowledge and experience with me.

Current set-up:
2002 Air Nautique (DD)
GT-40 (825-hrs)
WOT: 4,500 RPM (40-mph)
ACME-422 (12.5" dia // 15.5" pitch // .105 cup // RH)
Current elevation: 4,500' Msl
Slalom 32-34-mph (no course), wakeboard 16-18-mph, just started to wake surf 10-12-mph
Max ballast: 1,600-lbs, 2x adults 340-lbs, 2x kids 90-lbs = 2,030-lbs in the boat

I am currently looking at changing my prop out for something that can help me out in a wide range of areas as you can see. I talked with Tod at ACME Props and he recommended the ACME-480 (13" dia // 12.5 pitch // .105 cup // RH). With his recommendation, he stated I'll have approximately a 500 RPM increase on the engine and about a 2-mph loss. At elevation, it'll be good, but if I drop in elevation I'll have to really watch my RPM's so I don't over-rev the motor. Just bring the throttle back if need be I'm told.

Here are my questions:
1.) Will the RMP increase cause me any issues in the long run? Do I need to worry about my motor?
2.) Would I be able to run this same set-up at sea level? A possibility that I could move at any time.
3.) I currently have 1.25" to 1.35" from the tip of the ACME-422 to the hull. If I go to 1" clearance, will this cause any harm to my hull?
4.) Will the ACME-480 be able to do all the sports my family does? Can I still ski and wife still surf? Or is this an effort in futility?
5.) What else would you recommend for me to run and why?

The family and I really love our boat (2nd owners, bought last year) and are not willing to swap out. And really can't afford anything else right now. So any help and advice you can pass my way would be very much appreciated. I will apologize up front that I am very busy and not so good at responding in a timely manner. Again, thank you all in advance.

V/R,
-Doug

[charlesml3]

Doug,

The very best thing you can do is call Delta Propeller at 513-467-0601 and go through all of this with them. They will help you get the right prop for your boat. Their customer service is outstanding.

-Charles

[dgfrinell]

Charles,

Thanks for the reply. I forgot to mention that I did call Delta Propeller yesterday and they said the ACME-480 could work at my current elevation, but weren’t really sure about being lower in elevation. They told me to call ACME and ask them what they thought. I didn’t tell Delta I had already talked with ACME.

Currently ACME has a 30-day return policy with their props...as long as I don’t damage it when testing it out. But it is not a money back thing, they will continue with me to figure out what prop will work for my needs. I just need to make sure I document everything during the testing phase, and have reasoning as to why the prop is not right for me. Delta does not have that option. If you buy and put on your boat...it is yours for all of eternity.

Again, thank you for the reply and advise.

V/R
-Doug

[kylem03]

I had an acme 1868 12.5x14.25 on my 94 sport that did a great job handling 2k ballast consistently and was also allowing for decent slalom without over-revving. I run at 1600 feet so probably a whole different animal but there’s a data point for you.

[dgfrinell]

Kylem03,

Thanks for the data. I saw that prop, but havent’ heard much on it. Thanks for the push. Enjoy.

V/R
-Doug

[a0128]

You should also consider the Acme 654. I have this prop on my 1999 Pro Air. Good compromise between the 422 (better for slalom) and the 480 (heavy weight). Based on your elevation I can understand why the 480 was recommended, but I think the 654 would be a better all-around prop and work in a lower elevation.

[dgfrinell]

a0128,

Thanks. I was looking at the 654, but just didn’t seem to have the extra little push I might need. But the 480 might just be a little too much push for me. I say this, and I’m still new and learning everything.

I just got off the phone with Kevin at Acme Proppeler, and we worked it out and came up with the 1868. The big reason is the ability for elevation and it should only raise my RPM’s about 200 to 300 above what I’m turning now, which brings me to my optimal WOT range. Here’s hoping. So I order the 1868 and it should show next Fri here in good ole NM. Plan is to get in on and out on the water that Sat and get a good test in. If there are issues, they will work with me for returns and work out another option. Good company so far.

Going out tomorrow and get a good test on the 422, so I can have a good comparison next week. Thank you for the advice and I’ll let you know what becomes of all this. Now to tell the wife I bought a new prop. Wish me luck.

V/R,
-Doug

[beamons]

a0128,

Going out tomorrow and get a good test on the 422, so I can have a good comparison next week. Thank you for the advice and I’ll let you know what becomes of all this. Now to tell the wife I bought a new prop. Wish me luck.

So how did it go? I am looking for data on the 1868 at elevation.

[MTRBTR]

I had the 422 the 1868 and the 654 on my 1997 sport. The elevation thing is way over blown. I live in Bozeman MT and often went to Hebgen lake which is at 6535' elevation.
I will tell you that the 1868 will make your boat scream at slalom speeds. I could only get 37 MPH out of it at full throttle. You basically dont have any more speed with once you get past about 3900 RPM with the 1868. (it did have some awesome hole shot though) I had the 422 and it actually did fine even for surfing. I settled on the 654 and was most happy with that one. It worked the best. Good hole shot, good slalom, and we would sack out and surf and it did fine there too.
I have talked to those ACME guys several times before and if you tell them that you put any type of weight in at all they will always recommend pitch that is way too low. I think they just have some chart they go off of with no experience. I dont think you will be happy with Top end at all with the 480.

[dgfrinell]

So how did it go? I am looking for data on the 1868 at elevation.

Beamons,

Sorry for not getting back to everyone earlier with this, been a bit busy.

We found we really like the ACME-1868 for all-around play. I'm keeping my 422 for my back-up, still a great prop, but the 1868 is working just a bit better for us...right now.

Pros:
- Great hole shot
- Better throttle control/response while surfing (compared to the 422)

Con's:
- RPM's raised 300 over the entire RMP range (not really bad in the long run)
- Maxed out at 38 MPH (4800 RPM / for some reason I just can't get any higher than that)
- Bit more of a bump when Slalom at 32-34 MPH (but overall doesn't seem that fast at all...found out the hard way)

With regards to elevation, if I was only skiing, I would have stayed with the 422, but kids and wife like slower speed sports than I do. For pushing weight around the lake in a small direct drive, the 1868 works well for us. Hope this helps.

V/R,
-Doug