Baller mbabiash Posted September 29, 2018 Baller Share Posted September 29, 2018 I’m sure the boat companies have researched this to no end but while watching F1 this morning I was thinking about aerodynamics and my thoughts went to hydrodynamics and boats. It seems that all the research and tuning is in the hull running surface and the skegs and rudders have always been the same. It seems that handling on boats could be improved with a new design of skegs and rudders without affecting wake size. I know nothing about this, I just thought it was interesting. Link to comment Share on other sites More sharing options...
Baller BraceMaker Posted September 29, 2018 Baller Share Posted September 29, 2018 Check out Boesch boats bulge rudder Link to comment Share on other sites More sharing options...
Baller thager Posted September 29, 2018 Baller Share Posted September 29, 2018 Didn't the 2000 DisasterRaft have a wing on the rudder? Anyone have a pic? Todays tracking fins and rudders need holes!!!! Link to comment Share on other sites More sharing options...
Baller Dacon62 Posted September 29, 2018 Baller Share Posted September 29, 2018 More could be done just don’t know how much of an improvement can be achieved and at what cost? My ‘92 California Skier had a piece of ‘new tech’ called an EP (equal pressure) rudder. It had a sharp front edge and a fat 1” or so trailing edge. It was shaped like an axe head. They claimed it helped tracking because there was equal pressure on both sides of it so the rudder was loaded all the time. Sounded good to me. Didn’t feel any different if I recall. Don’t see them on any new boats so I guess it wasn’t accepted by builders or boaters as being an improvement. The Boesch rudder looks like a similar product in design. Anyone drive or ski one of these Boesch boats and could comment on rudder feel or tracking? Link to comment Share on other sites More sharing options...
Baller ForrestGump Posted September 29, 2018 Baller Share Posted September 29, 2018 @thager the MC had a wing on the rudder because without it the boat would chine lock in a tight turn and run onto shore. Typically, the end of a good ski set. Link to comment Share on other sites More sharing options...
Baller pcmcon729 Posted September 29, 2018 Baller Share Posted September 29, 2018 Thager that was a 95ish MC. That was a fix to a stabilization issue along with retrofitable aft chine inserts. 2000 was a new hull design that was used until 2013 I believe. Link to comment Share on other sites More sharing options...
Baller Dacon62 Posted September 29, 2018 Baller Share Posted September 29, 2018 IIRC The hull in question was built from 98-00. The chine inserts and rudder wing followed to try and solve some handling issues until 2001 model year when they built another new hull. Link to comment Share on other sites More sharing options...
Baller_ MISkier Posted September 29, 2018 Baller_ Share Posted September 29, 2018 @Dacon62 has it right. 1998 to 2000 on the Prostar 190 were the years with the issue. Note that it did not affect the other models of that era (Prostar 195, SportStar, Skier 19, Prostar 205). Only the 190 had that hull and the problem. Those other models were based on the 1995-1997 hull, which was a very fine hull free from the safety/handling concerns. 2001 was the start of the Prostar 197 hull. The worst slalom equipment I own is between my ears. Link to comment Share on other sites More sharing options...
Baller_ DW Posted September 30, 2018 Baller_ Share Posted September 30, 2018 @mbabiash: There is always room for improvement although it does come down to ROI in the case of a consumer product v the outright search for speed with pretty much an unlimited budget for the F1 gang. It is pretty amazing how much time and effort is spent in a wind tunnel for the top F1 teams, the fan spins pretty much 24/7. There are improvements by simply doing some basic blueprinting of your existing skegs, rudder and rudder support. One can improve efficiency and also tune the torque steer with appropriate modifications. One of the product improvements has been the adjustable tab introduced by Malibu, another product is the Acme prop cone, not commonly used but installs at the trailing edge of the prop. As you note, much more effort and time is devoted to hull changes to tune and improve the wake, a lot has to do with which axis the component acts. Link to comment Share on other sites More sharing options...
Baller dvskier Posted September 30, 2018 Baller Share Posted September 30, 2018 @DW pretty sure that Nautique introduced the tunable rudder tab in 1998. Link to comment Share on other sites More sharing options...
Baller_ Jody_Seal Posted October 1, 2018 Baller_ Share Posted October 1, 2018 @DW, Actually no we had to pay royalty's on an existing design. If you look at a original 11-A "tabbed" rudder you will see a "Z" marine Hardware logo on it.. Link to comment Share on other sites More sharing options...
Baller BraceMaker Posted October 1, 2018 Baller Share Posted October 1, 2018 Thread is kind of proving the point @mbabiash proposed - not a whole lot going on. More maybe in the world of surf boats with things like dockstar. But the reality is that you need fairly robust hardware underwater to put up with the strains, props have seen some big leaps w/ CNC. Maybe if a company saw fit to CNC the rudders and skegs you could get fancier. Rudder tabs are just a solution to hand tuning the rudder. Rudder winglets were just a solution till they got the hull hooked. I've always felt it wouldn't be horrendous to figure out some form of pylon actuated tracking control. A physical or hydraulic linkage the pylon bolted into with a mechanism such that angle + force would dog track the boat. I figured this would be easier to implement if ski boats used power hydraulic steering like I/O's as you could easily use the deflection to port fluid pressure and influence both the skegs and the rudder. But people like the "feel" of cable steering in these boats. Link to comment Share on other sites More sharing options...
Baller_ DW Posted October 1, 2018 Baller_ Share Posted October 1, 2018 The last two comments remind me of one of my college professors who said on day 1 of an engineering design class: "show me something new and I will give you an A for the class". We thought, damn, this should be easy! Well, by class end none of us succeeded in the 'easy A' since every time we brought something up, he could get some old dusty textbook and basically show us it had been introduced long, long ago:) The rudder tab was merely an example not necessarily meaning it was the first or only. Link to comment Share on other sites More sharing options...
Baller BraceMaker Posted October 1, 2018 Baller Share Posted October 1, 2018 @Dacon62 - it pulled the worlds last year but I never heard driver feedback from it. Also in continuation to previous post - I think its more likely to address this now in an accelerometer/servo type apparatus instead of using hydraulics - even cars are moving away from powered hydraulic steering. Link to comment Share on other sites More sharing options...
Baller Dacon62 Posted October 2, 2018 Baller Share Posted October 2, 2018 So throughout the years here are the tracking fin/strut/rudder advances/fails. In no particular order and to the best of my recollection from front to back, 1) SKEG, Centurion articulating tracking system(CATS)-a front skeg that moves opposite to the rudder to supposedly improve tracking. Introduces in the 90's on the Tru Trac III hull. Not used on their ski boats anymore but the tech has found its way to the wake surf boats. 2) STRUT, Mastercrafts strut dongle that protruded out the front of the strut to smooth out water flow to the prop. I don't recall seeing this on MC's or any other brands for some time now. 3) RUDDER, A)Rudder tab to adjust rudder torque. Still used and a great idea. B)Axe shaped E.P. ((equal Pressure) Rudder. No longer used. C)MC's winged rudder around 2000. No longer used. So of all the attempts at improvements the only item still being manufactured is the rudder tab. Please add to the list as I would expect that something was missed. @DW could you post a pic of the Acme prop cone? Link to comment Share on other sites More sharing options...
Baller_ DW Posted October 2, 2018 Baller_ Share Posted October 2, 2018 @Dacon62 : click on link for pic: volvopentastore.com/Prop-Fair-Water-Cone-Acme-Props/dm/store_id.366--view_id.1183951 4) Insert picture of a grinder:) Which may be the most effective for the slalom gang. Link to comment Share on other sites More sharing options...
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