68" Radar MPD / Pro Ski Coach Water Ski Forum

Darin Montgomery · #1 Tue, Jun 19, 2007 4:42 PM

Chris,

I have been trying to get my 68" MPD set up with little success. Rini and I have traded emails but none of the set ups are working. Andy suggested I use the HO fin since they are out of the black fins. I would like to mount the Powershells on the MPD and give it another ride. Especially, after watching you rip it at the shoot out. I noticed several other riders rip’ in the MPD, so I know the ski rocks. What binding set up would you recommend using?

Also, what are your thoughts on ski size? I am 198lbs, 6'-1" and typically run mid-39 @ 58k.

These were the last fin settings using the Gold fin:

L 6.850 (tips)
D 2.50
T .74
W 8 upside

Front Binding: 29.75"

Thanks,
Darin

ChrisRossi · #2 Tue, Jun 19, 2007 6:12 PM

Darin,
My thoughts would be to start at the following settings with the HO fin:

Bindings 29.75
2.500
6.850
0.790
9 degrees

Ski it and let me know what you like and what you want to be better.

Chris

Darin Montgomery · #3 Thu, Jun 21, 2007 1:26 AM

Chris,

The ski was better with the HO fin. It seems like you need to run more speed for the ski to work well. My on-side was good, not great; the offside did not finish and blew out on one of my 35's. The ski kept bouncing off the second wake heading into my offside and would occasionally wheelie. What would you suggest I change?

Shark · #4 Thu, Jul 19, 2007 6:10 AM

I just got a 68" MPD. I'll be setting up at 30.25, going straight to our CR fin, just because of the size of the ski and our water. Hopefully everything works out and the ski is not too stiff, since I am 185lbs. The tail feels good - it's pretty stout under the boots and a lot stiffer than my 1.1 Sixam.

Anyway judging from what you are saying you might try to settle the ski down with a 30" boot position and DFT at 0.800. There are other changes you can make too, but that is where I would start. All depends on what type of water you are on.

ChrisRossi · #5 Thu, Jul 19, 2007 11:12 AM

I agree with Shark on this one. Those moves should feel great.

Chris

Darin Montgomery · #6 Tue, Jul 31, 2007 3:00 AM

Chris,

I tried Shark's suggestion and I cannot get the ski to turn on my offside at all. I feel good coming into the turn but the ski will not finish. I noticed during my turn in for my gate, LFF, the ski is proposing as I get to the first wake. Any thoughts?

Thanks,
Darin

Shark · #7 Tue, Jul 31, 2007 6:06 AM

When a ski rolls on edge two things happen - it starts to take on a new planing surface - as defined by the sidewall & the bevel as it's the interface between the two. Also the fin starts to deliver its force on the tail, defined by the settings of the fin. This is supposed to nose the ski in, controllably.

I've seen skis bounce before. I figure it is like a boat. Too much weight or force (from the fin) pulling the ski up out of the water, until there is not enough surface to support you, then the ski comes crashing back in. Repeat.

So to correct that you need to reduce depth and increase length all in one go -and in doing so maintain the same fin surface area. Too late (11pm) to check exactly but the numbers will be something like

... 6.915, 2.475

To go to the limit, our CR fin will give you numbers that you can't achieve with a stock fin. I am getting some made up for MPD with a thickness of 0.100".

ChrisRossi · #8 Wed, Aug 1, 2007 12:12 PM

Darin,
Give me another day on this. Working with the legend on a solution.

ChrisRossi · #9 Thu, Aug 2, 2007 5:30 PM

Darin,
Here is what Andy had to say:

I would suggest 29 7/8” 2,505 6.840 0.785 7

This will feel different, but should let the ski flow more and carry speed through the turn.