Prop questions holeshot versus top-end

[areamike]

Mike, I'm going to guesstimate that the ACME 13x14 will spin 5200-5400 RPM on your boat. Anyone else care to offer a prediction? Maybe we should have a pool or something!

Thats' what I'm hoping for

How about a acme 1257. Still a 13x14 3blade but with a lot of cup (.135) That might prevent the cavitation that you are seeing. If you get it to grip rpms should drop ~300 and speed should shoot up. With the huge blades, it should be very strong and stable.

I saw that one too. I mentioned it to Bill from ACME after he suggested the 1595 13x14 .80 but I have not heard back yet. the 1595 is new he said.

That's also what I was wondering, more cup=less slippage?

[UWSkier]

I say go 13.5x17.5 4 blade and add aviation gas and a turbo. Sounds like the internals are all turbo friendly already.

[areamike]

WOW, these ACME props are expensive AND you have to pay shipping both ways. I guess OJ definitely beats them in those areas.

[badbyz]

WoW is my prop too big??

My boat came from the factory with 13.5 x 17.5 .150 four blade ACME

I have a Hammerhead 383. Seems to top out around 48mph at 5200.

Help I am very new to inboard boats and after reading this forum...very confused.

[NorCaliBu]

WoW is my prop too big??

My boat came from the factory with 13.5 x 17.5 .150 four blade ACME

I have a Hammerhead 383. Seems to top out around 48mph at 5200.

Help I am very new to inboard boats and after reading this forum...very confused.

Different boats. The boat of discussion here is a direct drive (1:1), your boat is a v-drive and v-drive units have a gear reduction in them.

[electricjohn]

WoW is my prop too big??

My boat came from the factory with 13.5 x 17.5 .150 four blade ACME

I have a Hammerhead 383. Seems to top out around 48mph at 5200.

Help I am very new to inboard boats and after reading this forum...very confused.

Those numbers just don't add up for me. Are you sure you read the prop right, or perhaps the v-drive has a gear reduction? That's a prop you would see on a Mastercraft with powerslot or a Nautique.

[areamike]

How about a acme 1257. Still a 13x14 3blade but with a lot of cup (.135) That might prevent the cavitation that you are seeing. If you get it to grip rpms should drop ~300 and speed should shoot up. With the huge blades, it should be very strong and stable.

Bill from ACME said the only motor they have found so far that stays within it's power band with that prop(1257) is the big 8.1 Indmar.

[D-GOOSE]

How about a acme 1257. Still a 13x14 3blade but with a lot of cup (.135) That might prevent the cavitation that you are seeing. If you get it to grip rpms should drop ~300 and speed should shoot up. With the huge blades, it should be very strong and stable.

Bill from ACME said the only motor they have found so far that stays within it's power band with that prop(1257) is the big 8.1 Indmar.

Yep with those numbers that the only one.

[areamike]

How about a acme 1257. Still a 13x14 3blade but with a lot of cup (.135) That might prevent the cavitation that you are seeing. If you get it to grip rpms should drop ~300 and speed should shoot up. With the huge blades, it should be very strong and stable.

Bill from ACME said the only motor they have found so far that stays within it's power band with that prop(1257) is the big 8.1 Indmar.

Yep with those numbers that the only one.

He also said that if my boat spins the 13x14 .80 (1595)- very doubtful it will. then we would try the 1257 after that. The 1595 is a new prop he says.

[Eric Johnson]

How about a acme 1257. Still a 13x14 3blade but with a lot of cup (.135) That might prevent the cavitation that you are seeing. If you get it to grip rpms should drop ~300 and speed should shoot up. With the huge blades, it should be very strong and stable.

Bill from ACME said the only motor they have found so far that stays within it's power band with that prop(1257) is the big 8.1 Indmar.

Yep with those numbers that the only one.

He also said that if my boat spins the 13x14 .80 (1595)- very doubtful it will. then we would try the 1257 after that. The 1595 is a new prop he says.

I will have a new 3-blade avialable to test next week that may help your situation, assuming you would be will to give OJ another shot. I also have a 4-blade propeller, a FORCE Hand finished, yes they still exisist, that would be worth a run too. Give me a call direct if you'd like to discuss. Thanks, Eric @OJ PROPS 800-359-9730.

[areamike]

How about a acme 1257. Still a 13x14 3blade but with a lot of cup (.135) That might prevent the cavitation that you are seeing. If you get it to grip rpms should drop ~300 and speed should shoot up. With the huge blades, it should be very strong and stable.

Bill from ACME said the only motor they have found so far that stays within it's power band with that prop(1257) is the big 8.1 Indmar.

Yep with those numbers that the only one.

He also said that if my boat spins the 13x14 .80 (1595)- very doubtful it will. then we would try the 1257 after that. The 1595 is a new prop he says.

I will have a new 3-blade avialable to test next week that may help your situation, assuming you would be will to give OJ another shot. I also have a 4-blade propeller, a FORCE Hand finished, yes they still exisist, that would be worth a run too. Give me a call direct if you'd like to discuss. Thanks, Eric @OJ PROPS 800-359-9730.

Thanks Eric. I'll be glad to give you a holler once I am done testing the ACME prop they are sending if it does nto work as expected. I still do not believe that a 4 blade prop is at all a match for my boat and power. However, I could be wrong.

What is the size/pitch and cup of your new 3 blade?

[Eric Johnson]

How about a acme 1257. Still a 13x14 3blade but with a lot of cup (.135) That might prevent the cavitation that you are seeing. If you get it to grip rpms should drop ~300 and speed should shoot up. With the huge blades, it should be very strong and stable.

Bill from ACME said the only motor they have found so far that stays within it's power band with that prop(1257) is the big 8.1 Indmar.

Yep with those numbers that the only one.

He also said that if my boat spins the 13x14 .80 (1595)- very doubtful it will. then we would try the 1257 after that. The 1595 is a new prop he says.

I will have a new 3-blade avialable to test next week that may help your situation, assuming you would be will to give OJ another shot. I also have a 4-blade propeller, a FORCE Hand finished, yes they still exisist, that would be worth a run too. Give me a call direct if you'd like to discuss. Thanks, Eric @OJ PROPS 800-359-9730.

Thanks Eric. I'll be glad to give you a holler once I am done testing the ACME prop they are sending if it does nto work as expected. I still do not believe that a 4 blade prop is at all a match for my boat and power. However, I could be wrong.

What is the size/pitch and cup of your new 3 blade?

The new size of the new prop will be....well....lets just say I'll keep the size under my hat until you run it. The 4-blade I was suggesting is the prop that I built for the orginal Monsoon motors, the early motors that would really run, at a max of 4800 -5000 RPM. The new version of the Monsoon cannot pull this propeller anymore even with the small amount of cupping, .090. So, I would think that propeller with .120 cup could run well for you. For me, more than .120 of cup is a bit much. Yes, more cup will pull the motor down but a better way to do that ,imho, is to be more creative with pitch.

[NorCaliBu]

What is the size/pitch and cup of your new 3 blade?

The new size of the new prop will be....well....lets just say I'll keep the size under my hat until you run it...

Saw that coming. Good for you Eric.

[areamike]

What is the size/pitch and cup of your new 3 blade?

The new size of the new prop will be....well....lets just say I'll keep the size under my hat until you run it...

Saw that coming. Good for you Eric.

oh, it's that way? I'd tell ya but I'd have to kill ya...

[Eric Johnson]

What is the size/pitch and cup of your new 3 blade?

The new size of the new prop will be....well....lets just say I'll keep the size under my hat until you run it...

Saw that coming. Good for you Eric.

oh, it's that way? I'd tell ya but I'd have to kill ya...

Something like that, yes. A prop guy has to have some secrets to avoid soemthing like an Ambush from...another prop guy as long as one can.

[areamike]

Well call me Mr. Bigmouth , I just sold out ACME...oops

[Eric Johnson]

Well call me Mr. Bigmouth , I just sold out ACME...oops

Not a bigmouth at all. Truth be told, what I call a 13 X 14 and what brand X or Y calls a 13 X 14 are not the same,(unless the prop is a Ambush by Michigan Wheel then it is the same as it is a copy of an OJ, Ambush reference) close but not the same thing. The way we look at pitch distribution, as we distribute pitch acrros the blade differently than most, determines a median pitch number that we designate the prop as. So, our 14 could be more or could be less than 14. Make sense yet?

[areamike]

Well call me Mr. Bigmouth , I just sold out ACME...oops

Not a bigmouth at all. Truth be told, what I call a 13 X 14 and what brand X or Y calls a 13 X 14 are not the same,(unless the prop is a Ambush by Michigan Wheel then it is the same as it is a copy of an OJ, Ambush reference) close but not the same thing. The way we look at pitch distribution, as we distribute pitch acrros the blade differently than most, determines a median pitch number that we designate the prop as. So, our 14 could be more or could be less than 14. Make sense yet?

Clear as mudd

just kidding, yeah I understand.

[hotrodbowtie]

Just throwing myself under the bus, but, since you were coming from a 13x13 SS propeller, that would be equivalent to a 13x14 brass. (This is all from past rememberance). SS vs brass is equivalent to 1p. All things equal, I am guessing that a 13x14 SS would give you what you need, which would probably be a 13x15 brass with about .6 to .8 cup. Now all of this is subject to varying pitch numbers that Eric was mentioning combined with the fact that my nibral experience is more with WB props.. This throws a whole new thought on the table. My personal opinion is that three blades run better for speed applications and 4 blades run better for power applications. This should really start something that I cannot finish. On my ws247 with a hammerhead, I run a three blade (acme 13x15.5) I believe. I do not need all of the low end grunt and I ski as well as go for cruises, so I want to keep the rrrs down at speed a bit. The hammerhead and the 8.1 use different tranny's, so this was my compromise. I think that it works very well for my applications.

[areamike]

Just throwing myself under the bus, but, since you were coming from a 13x13 SS propeller, that would be equivalent to a 13x14 brass. (This is all from past rememberance). SS vs brass is equivalent to 1p. All things equal, I am guessing that a 13x14 SS would give you what you need, which would probably be a 13x15 brass with about .6 to .8 cup. Now all of this is subject to varying pitch numbers that Eric was mentioning combined with the fact that my nibral experience is more with WB props.. This throws a whole new thought on the table. My personal opinion is that three blades run better for speed applications and 4 blades run better for power applications. This should really start something that I cannot finish. On my ws247 with a hammerhead, I run a three blade (acme 13x15.5) I believe. I do not need all of the low end grunt and I ski as well as go for cruises, so I want to keep the rrrs down at speed a bit. The hammerhead and the 8.1 use different tranny's, so this was my compromise. I think that it works very well for my applications.

If that is the case then this 13x14 I am getting from ACME should produce pretty much the same numbers I am getting now, which is not what I want. We shall see. I may end up having Eric send me his prop to test, but I don't want him to waste his time if it is not necessary.

[Eric Johnson]

Just throwing myself under the bus, but, since you were coming from a 13x13 SS propeller, that would be equivalent to a 13x14 brass. (This is all from past rememberance). SS vs brass is equivalent to 1p. All things equal, I am guessing that a 13x14 SS would give you what you need, which would probably be a 13x15 brass with about .6 to .8 cup. Now all of this is subject to varying pitch numbers that Eric was mentioning combined with the fact that my nibral experience is more with WB props.. This throws a whole new thought on the table. My personal opinion is that three blades run better for speed applications and 4 blades run better for power applications. This should really start something that I cannot finish. On my ws247 with a hammerhead, I run a three blade (acme 13x15.5) I believe. I do not need all of the low end grunt and I ski as well as go for cruises, so I want to keep the rrrs down at speed a bit. The hammerhead and the 8.1 use different tranny's, so this was my compromise. I think that it works very well for my applications.

If that is the case then this 13x14 I am getting from ACME should produce pretty much the same numbers I am getting now, which is not what I want. We shall see. I may end up having Eric send me his prop to test, but I don't want him to waste his time if it is not necessary.

Never a waste of time to send a prop. More of a waste to have it sit here if it will help your application.

[areamike]

Results from ACME 13x14 .80 (part#1595)

34mph@ 3200RPM

40mph@ 3800RPM

50.4MPH@ 5200RPM @ WOT down river

49.5MPH@ 5200RPM @ WOT up river

Not BAD results, but I'm not crazy about the loss of RPM at 34 and 40. The hole shot was really really good.

I wouldn't mind trying your prop Eric. I'll give you a call.

I have 3 props on their way back to SkiertoSkier...I'm getting prop crazy

[hotrodbowtie]

Mike,

Based on those numbers, if you drop the pitch to 13.5 and keep everything else the same, you should raise your rpm's 200, but speed may drop off. You could also drop the cup slightly to .5 or .6 and that might gain the rpm without loosing speed.

trying to be helpful :)

[edwin]

Slight hijack - first sets of the year today, joined by Galaxy Toad - I love my Edwin special OJ XMP. Thanks Eric for building a great product!

[areamike]

Mike,

Based on those numbers, if you drop the pitch to 13.5 and keep everything else the same, you should raise your rpm's 200, but speed may drop off. You could also drop the cup slightly to .5 or .6 and that might gain the rpm without loosing speed.

trying to be helpful :)

I'm going to put my 13x13 CVP back on her tomorrow and re-test that prop to make sure my previous numbers were right.

If we could get the overall lower range RPM's up a little, that would be great. After talking to a skiing buddy he agreed that a 13x13.5 might be the right nitch and then it would be a matter of tweaking the cup to get it as close to perfect as possible.

I've changed props so many times in the last week and a half,, my prop shaft is just a nub...

Also, when I try the prop from Eric, I may get totally different results. Funny how a 13x13 ACME and a 13x13 OJ are not the same prop even with the same pitch.

Overall, I've gotten the best results from the ACME, however it is not to my satisfaction.