For the last number of years or since the advent of Zero Off I have been trying to find ways to eliminate the Zoom feeling that Zero off gives me going into and off the wakes . Setting's do not seem to help just moves the Zoom elsewhere in the work Zone Process. What I call the zoom is the feeling and consequences that happens with us skiers that don't really have the "good" slalom technique that the ZO system was designed for. Also the bigger slalom skier with old school technique that tend to get deep at the buoy can get zoomed as the system has a real tendency to over react. After being slammed into the wake and zoomed out of control off the second side Because I was not as stacked as I could be or in layman's terms had my Ass dragging and trying to get to the next buoy nor getting the chance to get the ski back under me as ZO will not allow that. I felt that their has to be a way to minimize the crappy feel of ZO for skiers such as myself. Keep in mind we used to be able to get the job done with the previous speed control (Perfect Pass) as the score book did not care what it looked like.
After trying to analyze and manipulate the system to minimize the Zoom feel by Toning or running slower in practice mode I decided to take a look at how the power is being transmitted to the water, what I found was that in a lot of cases propeller slip was not my friend in this process and that a propeller with less slip tended to not give me that Zoom feeling. One Boat company that Runs the OJ products did not give me that Zoom feeling when skiing behind their boats however the other two did.....
With today's modern tournament boats they are bigger and heavier then that of the tournament boats we had 10 years ago, they have more HP and are in most way's less efficient then earlier models. Having a propeller that has to some degree increased slip will allow for the motor to run up a bit before it bites and holds firm getting these bigger boats up and down the lake. Now Propeller technology in a ski boat is still a Black art akin to alchemy in my mind however we do have combinations and a few known's that have made the boats be as efficient as current rules dictate. I guess where I am going is that most of the manufacturers of our boats currently being used are not considering how the prop works in conjunction with that of the speed control and overall skier feel. 16.95 or 16.08 and how fast it gets their is the only concern as far as boat performance is concerned or as is tested at our AWSA testing procedures, Hence Our manufactures rely on this testing as a standard even though it is a low standard as per AWSA.
These are my findings and are seat of the pants experience as I don't know that any kind of measurement can be made or manufactured to mathematically come up with desired results on a given craft (I could be wrong!). After having run my new 2012 200 and yes with a 450 hp motor and stock propeller I found my self feeling that old Zoom again if I got out of shape or was just not in the game and trying to get it back on the end of the string. Ordered a OJ 13X15.5 4 blade XMP propeller, with the 450 motor I had them put .120 cup in it. Wow what a difference it has made in the feel of the ZO pull. No more zoom and has made the boat feel quite a bit more docile. The hook up off the ball is quite a bit firmer yet it does not want to over react allowing me to keep the ski more in front of me and staying stacked, I can be in better shape to pre turn and keep the line tight. I also feel that the ZO RPM oscillation is minimized. Time are right their at 36 and 34 07-08/94-95 as is the all the buoy times.
I have run this combination on a number of 6 liter 200's and have made the boats feel tremendously better on the skier end and have received many compliment from skiers skiing with this combination.
On Saturday I took some photos of the ZO head unit at speed with out a skier (Base line RPM)and was surprised at what I found (not really!) top speed also increased over the stock prop by almost 2 mph.
Anyway I will be running the OJ combination on this boat for my personal usage. this setup is probably the best skiing Nautique I have ever owned and it has an incredible feel at the end of the string. However as it pulls tournaments it will have the standard "Tested" prop that it came with.
Also, maybe or maybe not but I also dont feel so beat up and tired after a slalom set with this set up, and at my age trying to continue skiing is a chore as it is.
Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.