A little different Stroker build

Joe,
Thanks for the feedback. My eyes have been opened quite a bit so far. I keep thinking why wouldn't more guys want to take out cup and add pitch. If the engine has the torque to spin it you would think that you'd get more overall performance. When you talk with prop guys, they insist that you need the cup or the boat shakes itself apart. I have to disagree at this point but I'm far from expert at this stage in my testing. FWIW, my stock prop slips and shudders horribly when you get on it but it's still the fastest prop to date. It immediately spins up to 5K+ RPM, shudders a little bit and starts to walk a little bit to the right but it still tries to pull. Virtually all of the other props tested (except the cupped Force) pull hard with very little slip but fall short on WOT MPH.
I'll take your prop along for the AmSkier reunion and let some guys try it out with their stock motors. I'll bet there are more than one who will want to keep it. If you do want to sell it, let me know what you want for it and I'll keep you posted.

Brian and Alan,
I've heard several reports just like yours and I keep expecting those same kind of results but so far have been very disappointed. The XMP has so far been the most positive. Like Alan stated, that prop pulled really hard all the way through the RPM range like a sports car but just didn't have the WOT MPH. I keep expecting that magic bullet that gives me 57MPH like you talk about. I don't know if my expectations are too high or just haven't found the magic bullet yet. It's been a learning experience for sure.

Dave,
My ears were ringing that weekend. I had a feeling there were some very heated discussions going on.

A little late now but as you experiment take note of prop to hub, prop to rudder and prop to hull clearance, some feedback there would be good to know. Any ill handling from any of the props at speed? I assume you boat has tracking fins?

GottaSki wrote: Excelent build, well done. Lot of people crap on it, but I found a late-model Federal to be a very good prop on my supreme, which is not not a distant stretch from your hull. Had superior efficiency, wake, and roost characteristics to many more exspensive, modern props.

Thanks Tom,
Yeah, it would be really interesting to get a new 13x14 federal and see what that prop does. That was my reasoning in trying the 13x14 Legend. My only dis on the stock prop is that it does have a lot of turbulence in the wake and the aforementioned slipping. Makes barefoot wake crosses difficult but not impossible. The Force and XMP both had distinctly smaller and smoother rooster tails observed from the boat. I would assume that would translate to a smoother wake table for crosses but have not been able to verify.
My daughter and I did do some slalom runs with the Force and the Legend. We both ski at 15 off which puts the rooster tail about 3 feet in front of the ski. Both of us noticed a smoother crossing so I have to assume barefoot crosses would be smoother also. It may just be the rebuilt prop creating the turbulence. Like I said, a new 13x14 federal would be an interesting try.

backfoot100 wrote: Thanks Tom, Yeah, it would be really interesting to get a new 13x14 federal and see what that prop does. That was my reasoning in trying the 13x14 Legend. My only dis on the stock prop is that it does have a lot of turbulence in the wake and the aforementioned slipping. Makes barefoot wake crosses difficult but not impossible. The Force and XMP both had distinctly smaller and smoother rooster tails observed from the boat. I would assume that would translate to a smoother wake table for crosses but have not been able to verify. My daughter and I did do some slalom runs with the Force and the Legend. We both ski at 15 off which puts the rooster tail about 3 feet in front of the ski. Both of us noticed a smoother crossing so I have to assume barefoot crosses would be smoother also. It may just be the rebuilt prop creating the turbulence. Like I said, a new 13x14 federal would be an interesting try.

I think we are on the same page. I'm a slalom junkie too. I run the 4-force 13x13, and the wake is the best of the bunch, the roost wash is markedly low, flat and wide , vs narrow and high with the acme's i've tried.
However, it feels that if I worked the engine over to push 5krpm or more, there would be too much parasitics vs other designs to see superior speed with the force.
If the 4-force didn't exist, the federal would be on. The federal had some marginally superior wake charateristics at 28-30 mph for the family, but I like 34-36 and that was where the force really shines.
I also like how it launches, the revs fome up faster then it digs pulls hard. The force could make things a little frothy in the table above 40, I never foot behind my boat, and when i did it was a friends 2001 or sanger

Here is some interesting info.

I have been asked numerous times what the cavitation plate on the transom is for and if it's specific to the Barefoot Skier. I have always originally thought that the Barefoot model specifically had the plate well before Scarpa made it so popular but I have since found out that all AmSkiers have the plate.
After talking with Boat Doc and reading numerous posts about hull hook, I decided to break out the level and take a few pics.
As you can see, there is virtually no power robbing hook in my hull that is common place in the CC's.
The cavitation plate is actually more of a trim tab than anything else. It would be very easy to remove this for that little extra that all the speed demons are looking for without touching a belt sander and totally destroying the hull, gelcote and wake characteristics that make this a ski boat.
I can already see Reid, Tim and Joe calling dibs on who gets the next AmSkier that comes up for sale. They don't come along near as often as a CC does.

From the forward most portion of the base plate


From the end of the transom


From the end of the plate itself.


The angle of the plate in relation to the hull.

backfoot100 wrote: The cavitation plate is actually more of a trim tab than anything else. It would be very easy to remove this for that little extra that all the speed demons are looking for ..

I would highly recommend not even trying doing that, not even once just to see the results... it may also function as trim tab and rooster tail shaper but it definitely also serves as a cavitation plate. The rudder extends well beyond the back of the boat and between that and it's relatively thick foil-like cross section it will very likely pull in air intermittantly at high speeds without that plate. That would result in intermittant inability to steer at high speeds, which I can from experience tell you is pretty much undesirable. Now, would I possibly play with a couple spacer washers on the front to level it out a bit....

Eddie, PLEASE buy this prop! Brand new Acme 431 on ebay for $235 shipped... smoking deal!

Acme 431