Nautique newbie - prop questions

[capcut]

Purchased a 1992 Ski Nautique about six weeks ago. Beautiful condition, had about 230 hours when purchased. It has the 285 horsepower 351. Runs very well. The boat has a 14x14 OJ prop, which I don't beleive is the correct prop. It appears to be an older prop. My wife and I are strictly slalom skiers. I have noticed that this boat has a significant prop wash or rooster tail, more so than other ski boats I have owned.

I am thinking of buying one of the new cnc Acme props, and am wondering if anyone has suggestions about which props might reduce prop wash and improve the wake for slalom.

I have seen several threads about props, but most are several years old. I guess I am thinking about the newer 3 blade cnc props, but really just want the most effective prop for my usage.

Working on getting boat pics for here as well.

Thanks,
Mark

[NautiqueJeff]

Mark,

You will get lots of answers from experienced people here. I would also suggest that you call our friends at Delta Prop. They can tell you exactly what you need for your situation. They also give a generous discount for members of PlanetNautique.

PlanetNautique Site Sponsors & Industry Discounts

[Mikeski]

I believe the stock prop from 1992 was a 14 x 16 OJ legend 3 blade. If you switch to the 13.5 x 15.5 Acme it will help to reduce the prop wash. I don't believe a good 14 x 14 should have more prop wash than a good 14 x 16. I always clean up the leading edge of my props by filing a little off the back side. Don't take too much off and take off the same from each blade. I have done it for years and have good results. I also use some 320 emery cloth to deburr the prop. I deburr the prop every spring as they somehow seems to pick up small nicks over a summer's use. I am probably doing more to my props than the average boater, then again, I am sure I am more picky than the average boater.

[TRBenj]

I bet that 14x14 does have a bit more propwash than the 14x16, as he'd be turning significantly more RPM at any given speed due to the lower pitch.

The Acme 3-blades are great... I run them pretty much exclusively on all of my boats (1990 Ski Nautique included). However, Acme doesnt make anything larger than 13.25x15 in a 3-blade, which is a tad on the small side for a Ski Nautique with the HO motor, assuming you want to keep WOT RPM's at the recommended 4800-5000 range (which will result in the best all around performance of the boat). Your best bet is probably an Acme 422 (4-blade) unless youre running significant ballast exlusively, or running at altitude.

Delta is a great shop to buy a prop from- great pricing and very good customer service. I dont put much stock in their prop recommendations though. I doubt they have tried all the props they sell on every single hull/powertrain combination they fit. Going straight to Acme for a recommendation isnt a bad idea, as they base their recommendations on the data they collect from users. Even better, go straight to the source- there are many people who have tried lots of newer props hanging out here on PN and CorrectCraftFan that know a bit about what works best.

[capcut]

Thanks for the info so far! Just wanted to add that I don't use ballast and am not at altitude. We ski the Mississippi River. Plan on skiing tomorrow after work.

I see the recommendation for the 4 blade Acme 422. I do understand that that is a good prop. I have never had a four blade prop and was wondering about 3 vs 4 blades. I know that has been discussed over the years. Also, it seems the newer 3 blades have more blade area than they used to.

[TRBenj]

Thanks for the info so far! Just wanted to add that I don't use ballast and am not at altitude. We ski the Mississippi River. Plan on skiing tomorrow after work.

I see the recommendation for the 4 blade Acme 422. I do understand that that is a good prop. I have never had a four blade prop and was wondering about 3 vs 4 blades. I know that has been discussed over the years. Also, it seems the newer 3 blades have more blade area than they used to.

All else being equal, the new CNC 3-blades outperform their 4-blade counterparts when it comes to top end speed- and the difference in holeshot is negligible due to the increased blade surface area. I prefer the 3-blades on my boats.

That being said, Acme does not offer a 3-blade that will keep your HO Ford in that hull below 5000 RPM... I wish they did. You really want to turn that motor in the 4800-5000 range for optimum performance. The 422 is probably going to be the best all around prop for that boat, though the 1490 (13x15.5) might be fun to try too. Both are 4-blades though.

I only run the 3-blades (612 or 1442) on my '90 because I built my motor to make power a bit higher in the RPM range (peak hp is @ 5200) than the factory PCM HO motors. I have a bit of experience trying different props on the No Wake Zone Ski Nautique hull (1990-1996), so I have a decent idea of what works best.

[Wac]

All else being equal, the new CNC 3-blades outperform their 4-blade counterparts when it comes to top end speed- and the difference in holeshot is negligible due to the increased blade surface area. I prefer the 3-blades on my boats.

That being said, Acme does not offer a 3-blade that will keep your HO Ford in that hull below 5000 RPM... I wish they did. You really want to turn that motor in the 4800-5000 range for optimum performance. The 422 is probably going to be the best all around prop for that boat, though the 1490 (13x15.5) might be fun to try too. Both are 4-blades though.

I only run the 3-blades (612 or 1442) on my '90 because I built my motor to make power a bit higher in the RPM range (peak hp is @ 5200) than the factory PCM HO motors. I have a bit of experience trying different props on the No Wake Zone Ski Nautique hull (1990-1996), so I have a decent idea of what works best.

I put a 422 on my '92 ski nautique with the standard 240hp ford engine and 1:23 to 1 trans... I am purely a slalom skier with stargazer as my speed control... the wakes seem just harder compared to the old 3 blade OEM prop, but I love the power out of the hhole with the 422.... that prop also raised the back end a bit and twisted the boat to the port side with all the torque/surface area from the 4 blade..... I'm wondering if a 3 blade could soften the wakes a bit, and still have a simliar holeshot for quick get-ups on into the course..... SO, which 3 blade would you suggest for this application??

[TRBenj]

I put a 422 on my '92 ski nautique with the standard 240hp ford engine and 1:23 to 1 trans... I am purely a slalom skier with stargazer as my speed control... the wakes seem just harder compared to the old 3 blade OEM prop, but I love the power out of the hhole with the 422.... that prop also raised the back end a bit and twisted the boat to the port side with all the torque/surface area from the 4 blade..... I'm wondering if a 3 blade could soften the wakes a bit, and still have a simliar holeshot for quick get-ups on into the course..... SO, which 3 blade would you suggest for this application??

I cant say i know what youre talking about with your statement in bold... the new CNC props have a lot more "bite" due to their blade surface area. This is most pronounced out of the hole, in sharp turns, etc. Not sure what you mean about raising the back end and twisting the boat.

Ive noticed very little changes in the wake going from prop to prop. My '90 has never done anything but plow (it has a slow hull that runs very planted) but I know a few guys who have experience with the Acme's raising the bow up slightly compared to the OJ's. The more planted (bow down) the boat runs, the smaller/softer the wake should be, in theory. Swapping between different Acme models should not make any difference though, regardless of the number of blades. The other thing that can affect how the wake feels is the rooster tail... the more RPM's youre turning at any given speed may have an effect on the firmness. More pitch = lower RPM's = softer rooster.

The 3-blades are all smaller in pitch than the 422, so you'll be increasing your RPM's across the board with any one of them. I would not expect to see an improvement to the wake or slalom skiing performance in any way. If youre after more holeshot or better top end (for barefooting, etc) then either the 470 or 1442 would be awesome props on that boat. I swap between the 1442 and 612 (470 with 1/4" more pitch), on my boat.

If you want to try and soften the wake and dont mind giving up a little top end, you may want to consider a new OJ XMP (428). It will turn lower revs than the 422 and may lower the bow slightly. Both may help. I didnt like the way it performed on my boat- it gave up too much top end for barefooting. You may like it though!

[Wac]

TRBenj - Thanks a ton for your reply! I guess my biggest gripe is the firmness of the wakes on my 92 with the 422 compared to the other boats I ski behind, 98 SN, 2004 SN, malibu response.... Those nautiques also have 4 blades, but the malibu is a 3 and my 92 is noticeably better at tracking and running straight through the course than all of those, but at 22, 28, 32 and 35 off the wakes are also noticeably firmer. I like the hole shot the 422 gave me over the OEM 14x16, as a side note, the RPMs are about 250 higher with the 422 than the OEM to get the same speed (ppass makes this easy to notice).

I guess from your comments above I am leaning toward the 1442 rather than the 470 to lower the RPMs a little from the 422 and maybe the 3 instead of 4 blades will have a little less turbulence also?? I'm hoping the 1442 is a better hole shot than the OEM also. (?) On another boat in my family, an 88 SN, i put a 540 on it instead of the OEM 13x13 and LOVED the difference!! Better hole shot, better mid-range power and higher top end... i never thought all that was possible with one prop!! So, i'm hooked on CNC props - i just need your help to make the right choice now that there are so many variations....I'm leaning toward going back to the 3 blade because that is how the boat was originally engineered (?)

sorry for the bold in my original post, that wasn't intentional. The "twisting" i spoke of was in relation to the ride of the boat that was altered when i went to the 422 on my 92SN... i had to add weight to the driver's side to level the boat with only a driver in it. I assumed the new lean to the port side was due to the increased surface area of the 422 that was "twisting" the boat to that port side... the bow of the boat did come down a little too when I went to the 422 as well.

Thanks for your help and comments!!

[skiinxs]

Mark,
I have a 422 with a little extra cup you are welcome to try to help you decide. (.130 cup vs .105). PM me and I will send you my phone number. (I am in Manchester)

[skiinxs]

TRBenj - Thanks a ton for your reply! I guess my biggest gripe is the firmness of the wakes on my 92 with the 422 compared to the other boats I ski behind, 98 SN, 2004 SN, malibu response.... Those nautiques also have 4 blades, but the malibu is a 3 and my 92 is noticeably better at tracking and running straight through the course than all of those, but at 22, 28, 32 and 35 off the wakes are also noticeably firmer. I like the hole shot the 422 gave me over the OEM 14x16, as a side note, the RPMs are about 250 higher with the 422 than the OEM to get the same speed (ppass makes this easy to notice).

I guess from your comments above I am leaning toward the 1442 rather than the 470 to lower the RPMs a little from the 422 and maybe the 3 instead of 4 blades will have a little less turbulence also?? I'm hoping the 1442 is a better hole shot than the OEM also. (?) On another boat in my family, an 88 SN, i put a 540 on it instead of the OEM 13x13 and LOVED the difference!! Better hole shot, better mid-range power and higher top end... i never thought all that was possible with one prop!! So, i'm hooked on CNC props - i just need your help to make the right choice now that there are so many variations....I'm leaning toward going back to the 3 blade because that is how the boat was originally engineered (?)

sorry for the bold in my original post, that wasn't intentional. The "twisting" i spoke of was in relation to the ride of the boat that was altered when i went to the 422 on my 92SN... i had to add weight to the driver's side to level the boat with only a driver in it. I assumed the new lean to the port side was due to the increased surface area of the 422 that was "twisting" the boat to that port side... the bow of the boat did come down a little too when I went to the 422 as well.

Thanks for your help and comments!!

The "twisting" effect you mention can be caused by different prop design. Different amounts of cup affect the trim of the boat the most. More cup = more effect. For instance, identical props with different cup, the greater the cup, the more the boat will torque to the port side in a RH rotation Nautique. It is usually a very slight difference, but it is there. (By torque, I am refering to leaning, not pulling.)
Dave

[NCH2oSki]

More RPM = harder wake (sort of a broad statement, but usually holds true.) Take inxs up on his offer to borrow the increased cup 422, that should be ideal for your aplication.

BTW did a local guy add the cup to the 422, or did you get it from acme like that?

[skiinxs]

More RPM = harder wake (sort of a broad statement, but usually holds true.) Take inxs up on his offer to borrow the increased cup 422, that should be ideal for your aplication.

BTW did a local guy add the cup to the 422, or did you get it from acme like that?

I had Acme modify a 422 (originally .105 cup) to the .130 cup. My thought process was to get a prop halfway between a 422 (.105 cup that was used on the 5.7 liter 196's) and the 668 (same 12.5X15.5 pitch but .150 cup) that was used on the 6-liter 196's. This prop actually worked really well on my '11 6-liter 200, brought the rpm's down quite a bit from the stock 12.5 x 15 .105 cup, and if anything made that great wake even softer.
Dave

[TRBenj]

I guess from your comments above I am leaning toward the 1442 rather than the 470 to lower the RPMs a little from the 422 and maybe the 3 instead of 4 blades will have a little less turbulence also?? I'm hoping the 1442 is a better hole shot than the OEM also. (?) On another boat in my family, an 88 SN, i put a 540 on it instead of the OEM 13x13 and LOVED the difference!! Better hole shot, better mid-range power and higher top end... i never thought all that was possible with one prop!! So, i'm hooked on CNC props - i just need your help to make the right choice now that there are so many variations....I'm leaning toward going back to the 3 blade because that is how the boat was originally engineered (?)

sorry for the bold in my original post, that wasn't intentional. The "twisting" i spoke of was in relation to the ride of the boat that was altered when i went to the 422 on my 92SN... i had to add weight to the driver's side to level the boat with only a driver in it. I assumed the new lean to the port side was due to the increased surface area of the 422 that was "twisting" the boat to that port side... the bow of the boat did come down a little too when I went to the 422 as well.

No, no, no- Im not sure how you got there based on my comments, but the 1442 will turn MORE rpm than the 422, by about 200. It has less pitch (15" vs. 15.5"), and thus, the extra revs. It will indeed improve your holeshot, but may make your rooster tail harder, and the pull "firmer" relative to the 422. I dont think you want to go this way based on what youre telling us. A cupped 422 is an option, as is the OJ 428, as well as the slightly larger props from Acme, like the 1490 and 1492. Personally, I really like the way the 3-blades perform, but neither OJ nor Acme make anything with more than 15" of pitch in a 3-blade with a 1" shaft, so the choices for a 1.23 boat are limited in that respect. Supposedly the manufacturers like the way the 4-blades work with our hulls and reduction transmissions. That hasnt exactly been my experience, but Im no world class skier either.

I havent noticed a difference in attitude (how high the bow rides) with different props on my '90, but what youre describing seems to be the opposite of what some of my buddies have seen on older boats switching between the Acmes and OJ's. We are all pretty much in agreement that the OJ's ski nice, but the Acme's are better performers (holeshot, top end, etc). Getting the bow down will help the wake, in theory (more surface area) while raising it will improve top speed.

Im a little confused by everyone's comments saying that props of various pitch can have an effect on the wake. Do you mean the wake or the rooster tail? I understand how increased RPM's = more turbulance = firmer rooster. I dont see how it can have an effect on the wake though- that is purely a function of how the hull moves through the water. Changing between props of similar design (ie, similar rake and blade surface area but different pitch) should not affect the attitude of the boat, and thus, have no effect on the wake. It would take a slightly different design (ie, a variation in rake) to see a difference in running attitude, which in turn may have a slight effect on the wake. Or am I way out in left field here?

FWIW, Im not too crazy about adding pitch to props. It just makes them less efficient, IMHO. While it can be helpful to dial in the RPM at a given speed, Ive found that props with extra pitch do not generally improve top end speed, even if they help dial in the WOT RPM's closer to the hp peak (which in theory should make the boat faster). Props with less cup and the proper amount of pitch seem to be more effective and efficient.

[Wac]

No, no, no- Im not sure how you got there based on my comments, but the 1442 will turn MORE rpm than the 422, by about 200. It has less pitch (15" vs. 15.5"), and thus, the extra revs. It will indeed improve your holeshot, but may make your rooster tail harder, and the pull "firmer" relative to the 422. I dont think you want to go this way based on what youre telling us. A cupped 422 is an option, as is the OJ 428, as well as the slightly larger props from Acme, like the 1490 and 1492. Personally, I really like the way the 3-blades perform, but neither OJ nor Acme make anything with more than 15" of pitch in a 3-blade with a 1" shaft, so the choices for a 1.23 boat are limited in that respect. Supposedly the manufacturers like the way the 4-blades work with our hulls and reduction transmissions. That hasnt exactly been my experience, but Im no world class skier either.

I havent noticed a difference in attitude (how high the bow rides) with different props on my '90, but what youre describing seems to be the opposite of what some of my buddies have seen on older boats switching between the Acmes and OJ's. We are all pretty much in agreement that the OJ's ski nice, but the Acme's are better performers (holeshot, top end, etc). Getting the bow down will help the wake, in theory (more surface area) while raising it will improve top speed.

Im a little confused by everyone's comments saying that props of various pitch can have an effect on the wake. Do you mean the wake or the rooster tail? I understand how increased RPM's = more turbulance = firmer rooster. I dont see how it can have an effect on the wake though- that is purely a function of how the hull moves through the water. Changing between props of similar design (ie, similar rake and blade surface area but different pitch) should not affect the attitude of the boat, and thus, have no effect on the wake. It would take a slightly different design (ie, a variation in rake) to see a difference in running attitude, which in turn may have a slight effect on the wake. Or am I way out in left field here?

FWIW, Im not too crazy about adding pitch to props. It just makes them less efficient, IMHO. While it can be helpful to dial in the RPM at a given speed, Ive found that props with extra pitch do not generally improve top end speed, even if they help dial in the WOT RPM's closer to the hp peak (which in theory should make the boat faster). Props with less cup and the proper amount of pitch seem to be more effective and efficient.

My mistake... I'm learning now!! Thanks for the patience here!!!

The original reason I switched to the 422 with the 240hp engine I have, is to turn a little higher RPM, to get further into the HP range where the most power comes from this modest engine. The idea being, that the perfectpass calls for power when under load from a skier and seemed with my boat that is was late to catch up. We all thought it might be "running" to catch up when the skier was in the no-load phase-then turn. We found that the newer boats we ski on, with the same 422 prop were softer pulling/wake crossing behind the boat than my old lower HP carb engine. Our conclusion was that my old boat must be accelerating more aggressively because it needs more help catching up after being pulled down from the pull of our 180-200lb 32-35 off skiers. My boat is hands down the firmest pull/wake crossing of the 2000 SN, 2004 SN with the same props (422's all around)... and we all run the stargazer perfect pass. My engine is well tuned, mallory ignition to replace the protech ignition, and the carb is relatively new. Our thought was that the EFI 300+ HP engines may NOT be getting pulled down as much and have less effort to stay at the correct speed thus softer feeling wake crossings.

Of course, I would rather find a prop to soften the firmness instead of buying a new boat - and my wife 2nds that motion! So I guess my question has really come down to this - rather than going back to my OEM prop - what is going to be the best modern prop that get's the firmness of my wake crossings down from where we are with the 422?? AND... if we decide that more cup on my 422 is the answer; is this something that ACME could modify if I sent this in to them???

Thanks!!!!!