Prop cup on a SN200

[HighAltitude]

I got a 2014 SN200 this summer to replace my old '99 SN. While I absolutely love the boat, the wake at 32mph still seems a bit firmer than my old 196. I live on a private lake at 7000 ft so I am running the 1868 (I have the 6.0L). The 654 seems a little better but the holeshot was a bit weak. Has anybody added some cup to the 1868 to try reduce the RPMs and hopefully get a softer wake? If so, what cup did you use? I was thinking of .150. I was also thinking of doing this to a 654 to see if I could get it to turn the same RPMs as the 422 at 32mph. Thanks in advance for any replies. -Marc

[LeonL]

Not an answer, but another question. Why not use a 422? With a 6.0 I would think power would not be a problem. I know a 422 will not cause a firm wake at 32 mph.

[Jody_Seal]

7000 ft is a tough one for any boat. I would stay away from the 422 at that elevation. Your really not going to help the wake with any propeller. Cupping up a 1868 is something that might bring the rpms down at ski speed. A three blade is what is preferred for overall performamce at those elevations.

[dbutcher]

I have no proof, but I believe adding cup to any prop will make the wake harsher, not softer. Jody is the expert though. You could also call Acme. Acme has done lots of field research on propellers, including the effects of different cups.

[Jody_Seal]

Propellers and effect's on wake are very subjective. More effect of manipulating wake on 200's can be attained via hydrogate adjusting, messing with the trailing edges (not recommended) of the hull or moving weight around forward and aft in the boat.

ACME propeller Design's are very aggressive and move a lot of water in a not so clean way. ACME design's have more inherent slip then that of a more rounded tip design propeller.

When I do cup testing on propellers it has noting to do with wake but everything to do with overall performance , Speed and acceleration and how it reacts to the speed control gain's. Meh! coming from the old world of 70'-80's and even 90's battle wagons, wakes on all of these new model boats are like butter..

[DW]

So to @dbutcher & @Jody_Seal comments, the question might be: Has anybody tested a particular brand prop that is tuned to same RPM at a given speed but with different pitch v cup dimensions (ie: less pitch & more cup) and identified the effect on slalom wake? Agree with Jody that typical testing is done to determine boat performance effects such as speed and acceleration characteristics. My experience on adding some cup to an Acme provided good boat performance results, probably due to reducing slip per Jody's comments for a better holeshot. The wake did not seem overly negatively affected but it was done a while back so personally I would want to repeat that evaluation.

[Bruce_Butterfield]

I'll bet a case of anyone's favorite adult beverage that if you have a group of skiers try a cupped vs non cupped prop behind the same boat that half will not be able to tell the difference and the other half will be split on which prop was "better".

 

Worrying about the effect of cupping on the wake of a modern boat is really anal, even by slalom skier standards:)

[rodltg2]

If you can't find a solution and cannot stand the wake any longer. I'd be willing to straight trade you for my 1999.