Righty or Lefty |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Posted: January-30-2013 at 8:01am |
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Tony,
Yes, cavitation would be the introduction of air. Under certain conditions you can get air around the rudder causing a rudder stall. I just did a search using "rudder stall" for key words and found some pretty interesting info. Some even had water tunnel pictures showing the effects of air around rudders. My X55 will rudder stall at times. It happens at about 7/8 throttle turning to port. The theory is the hull steps at the aft introduce an air pocket. |
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Tonali_III
Senior Member Joined: August-30-2004 Location: St. Louis, MO Status: Offline Points: 412 |
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Correct me I'm wrong (and I know you will), but cavitation would involve the introduction of an air source into the water stream to help induce separation of the boundary layer of water. Couldn't the rudder stall without introduction of such an air stream? A fluid is a fluid. |
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1974 Southwind 20
<a href="http://www.correctcraftfan.com/diaries/details.asp?ID=6752" rel="nofollow">1972 Mustan |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Another term that can be used is rudder cavatation.
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hotboat
Gold Member Joined: March-28-2009 Location: Conn Lake Pa Status: Offline Points: 814 |
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In my limited experience yes, I could turn the wheel all the way one direction and change nothing, for fear of what happened in the video I never tried turning it the other way, throttled down until it grabbed and told the plump fellow riding along to sit in middle of back seat unless he was looking to go swimming in a hurry
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Brian
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BuffaloBFN
Grand Poobah Joined: June-24-2007 Location: Gainesville,GA Status: Offline Points: 6094 |
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I get air foil as I'm a left seater too. Crtical angle of attack is somewhat simplified, but I see your point. Are we talking about water 'boiling' around the rudder so that the rudder can 'freewheel' for a time? Is it like jet wash from the hull designing Jody referred to feeding air back to the vitals? |
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Tonali_III
Senior Member Joined: August-30-2004 Location: St. Louis, MO Status: Offline Points: 412 |
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I understand the concept of rudder stall. The rudder exceeds a "critical angle of attack" with the flow of water around it. I understand this concept because this is what an airplane does when it stalls. Water or air, a fluid is a fluid and they behave in similar fashions. |
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1974 Southwind 20
<a href="http://www.correctcraftfan.com/diaries/details.asp?ID=6752" rel="nofollow">1972 Mustan |
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BuffaloBFN
Grand Poobah Joined: June-24-2007 Location: Gainesville,GA Status: Offline Points: 6094 |
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Rudder stall still baffles me. I guess I'll know it if I ever feel it.
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Florida Inboards
Senior Member Joined: December-27-2012 Location: Panama City, Fl Status: Offline Points: 265 |
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Jody, I like the way you explain things. You MUST be an engineer. You don't let judgement or opinion cloud the facts. You remind me of Woody. And that is saying a lot! I put a post of my engine build thread where I quote a conversation that I had with Woody today. To paraphrase Woody, it depends on the hull design or family of hull designs as to whether a righty or lefty conversion has a significant effect on how the hull behaves. [/QUOTE] Nope! Not an engineer! Educated masters degree from the school of Rayson Craft, Sanger,RickShaw,Karlsen,Correct Craft, MasterCraft, American skier and a minor in Hydroplane. Have a PHD in Obrien,Radar and HO. Like Otis Sistrunk Attended the "University of Mars" before going pro! Funny stuff. Learned a lot over the years just immersing myself in performance inboards for nearly 50 years. Spent all of the 90's working with the likes of my Bill Snook, Steve Meloon, Art Cozier and yes Woody. I posted the Video as it is a classic example of rudder stall misbehavior (handling)due to some sort of bottom imbalance also due possibly to Mechanical failure. Boat showed signs of problems early in the race and the driver probably should have put it on the trailer at that point. I have actually come close to making ski boats do very similar things at far slower speeds. Cause and effect, luckily the Correct Crafts most all on these boards own are of designs that do not exhibit such misbehavior, basically due to the concave sides and attention to rudder design. Some of The competitions ski boat hulls even to this day can be easily induced into unsavory misbehavior due in conjunction of their hull bottom and barrel sides and rudder deficiencies. Most all of the circle racer flat bottom's utilize right hand props and left hand engines... They drive off of the front of the engine not the flywheel side. As for C&C design and fabrication of these crafts, most all of the boats being built today initially come off of a cad program and their plugs are cut on a large router. Then the tool maker puts the finishing touch on the plug as per the designer and or design team deems and "pooF!" we have a boat plug to build a mold from! The old school tooling is becoming a lost art as are the craftsman that facilitate the Art form! |
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Money Talks! BS Walks! and loose change rides the bus!!!
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AAM196
Gold Member Joined: October-23-2012 Location: Pittsburgh, PA Status: Offline Points: 846 |
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Is that the mold for the new G328 hull? |
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65 'cuda
Platinum Member Joined: July-12-2005 Location: Cincinnati, OH Status: Offline Points: 1091 |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Same way you come up with yours, Pete. Wanna play some more? [/QUOTE] I go from history going way back to the days of the gentleman racer. They sure did lots of interesting things like hull steps back then. Lots of lofting by hand and plenty of experimenting. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Gary, Thanks for bringing me up to speed on the CNC machining. I wonder if CC has started using the process for their hulls? That's one big 5 axis CNC!! |
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Tonali_III
Senior Member Joined: August-30-2004 Location: St. Louis, MO Status: Offline Points: 412 |
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Tony, I have to ask you how you came up with this idea about old hull design. New hulls may be designed by CAD but tell me, how do they make the molds?? They are NOT CNC machined!!!!!!!! [/QUOTE] Same way you come up with yours, Pete. Wanna play some more? |
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1974 Southwind 20
<a href="http://www.correctcraftfan.com/diaries/details.asp?ID=6752" rel="nofollow">1972 Mustan |
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Tonali_III
Senior Member Joined: August-30-2004 Location: St. Louis, MO Status: Offline Points: 412 |
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Well put. |
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1974 Southwind 20
<a href="http://www.correctcraftfan.com/diaries/details.asp?ID=6752" rel="nofollow">1972 Mustan |
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65 'cuda
Platinum Member Joined: July-12-2005 Location: Cincinnati, OH Status: Offline Points: 1091 |
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Looks like these guys cnc theirs:
http://janseneering.wordpress.com/2010/01/18/34-boat-hull-mold-ready-to-go-out-the-door/ I'm guessing nearly every modern hull mold is cnc'd. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Tony, I have to ask you how you came up with this idea about old hull design. New hulls may be designed by CAD but tell me, how do they make the molds?? They are NOT CNC machined!!!!!!!! |
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Tonali_III
Senior Member Joined: August-30-2004 Location: St. Louis, MO Status: Offline Points: 412 |
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Jody, I like the way you explain things. You MUST be an engineer. You don't let judgement or opinion cloud the facts. You remind me of Woody. And that is saying a lot! I put a post of my engine build thread where I quote a conversation that I had with Woody today. To paraphrase Woody, it depends on the hull design or family of hull designs as to whether a righty or lefty conversion has a significant effect on how the hull behaves. I will agree that the effect on older hull designs, the effect is minimal. There simply was not the ability to make a hull or even study a hull that was so precise that propeller rotation played a large role in handling. In our present day of CAD hulls and computer aided wind tunnel(or water tunnel?) testing, we ARE able to design and manufacture a hull to such tight tolerances that any change outside of the factory will produce a result that needs to be compensated for. Are you educated as an engineer? designer? airplane pilot? |
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1974 Southwind 20
<a href="http://www.correctcraftfan.com/diaries/details.asp?ID=6752" rel="nofollow">1972 Mustan |
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TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
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I've seen both, but I'm going to guess those boats were adapted to the capsule and not built for it. There is of course some contreversy about the capsules and the seat belts, but I believe I heard they are mandatory for most this year. I think most of the K boats at Long Beach this past summer had them in the center. Personally I think they look best without, but after seeing a handful of boats literally break into hundreds of pieces and then having a beer later with the guy driving, they do work.
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phatsat67
Grand Poobah Joined: March-13-2006 Location: Indiana Status: Offline Points: 6149 |
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Why are the cockpits of the K boats on the port side instead of in the middle?
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Riley
Grand Poobah Joined: January-19-2004 Location: Portland, ME Status: Offline Points: 7952 |
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The trouble with owning boats with RH and LH engines is remembering which way the one you're driving is going to back.
Sometimes a RH engine can be had for less money than a LH, but definately not RH specific performance parts. |
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Tonali_III
Senior Member Joined: August-30-2004 Location: St. Louis, MO Status: Offline Points: 412 |
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I just glanced at this thread and have not read the whole gamut, so please forgive me.
But if you are interested in the righty vs. lefty controversy, I would suggest contacting the great guru of Correct Craft, Woody. If you are interested, just IM me your phone number and I will see if he will contact you. |
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1974 Southwind 20
<a href="http://www.correctcraftfan.com/diaries/details.asp?ID=6752" rel="nofollow">1972 Mustan |
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TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
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Alcohol is bad for your motor, really?
I would be pissed too, not very often someone does that to Scarlata with any kind of boat. Jody are the K Boats set up to turn one way? I remember the Crakerbox drivers saying it would flip if we turned it right. We had the K Boats at the drag race one year, very cool they don't usually travel this far from the west coast so they haven't been back. |
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peter1234
Grand Poobah Joined: February-03-2008 Location: United States Status: Offline Points: 2756 |
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yikes ....... anyone have a vega motor i can put in my boat ?
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former skylark owner now a formula but I cant let this place go
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Florida Inboards
Senior Member Joined: December-27-2012 Location: Panama City, Fl Status: Offline Points: 265 |
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http://www.youtube.com/watch?v=lCmtnrYipI4
Thought I would post a video that exemplifies an unsavory handling condition that is probably induced to having too much hook due to failed cavitation plate or it's operating hardware. situation sets up what may be described as rudder stall.. Anyway check out lap three where the boat exhibits a view of things to come. |
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Money Talks! BS Walks! and loose change rides the bus!!!
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AAM196
Gold Member Joined: October-23-2012 Location: Pittsburgh, PA Status: Offline Points: 846 |
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What?? Lol... I'm just saying backing to the right is convenient; especially if lake is busy or driver is lazy. Riding level in my sn is way more enjoyable though!
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TX Foilhead
Grand Poobah Joined: February-01-2009 Location: Kingsland TX Status: Offline Points: 2076 |
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If your pulling in so fast you don't have time to stand up and walk across to secure the boat you need to work on your technique. You can dock on either side, but I got to believe there was something that caused them to call the correct side port.
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74Wind
Grand Poobah Joined: August-02-2011 Location: Georgia Status: Offline Points: 2101 |
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My boats both deep-Vs so no leveling issues like a ski boat. Don't often boat solo, so much simpler to just let passengers worry about dock/lines on port side... For years my bro had a small classic 70something Sutphen with a 200. Kind of a much sexier version of the Donzi Sweet 16 with a giant outboard. What a rocket!...70mph plus but hardest boat I'ver ever docked........ I was born with a hereditary inboard disease I was born with and just can't fight generations on docking on the right side of a dock. Gotta love a Stars & Stripes...lets see some photos! |
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1974 Southwind 18
1975 Century Mark II |
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AAM196
Gold Member Joined: October-23-2012 Location: Pittsburgh, PA Status: Offline Points: 846 |
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Our 83 mc s&s backs to right due to the lh rotation.... easier to dock as driver can just grab dock but leans hard to starboard w/o passenger. I find my 99 sn levels out nicely onces on plane. |
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Florida Inboards
Senior Member Joined: December-27-2012 Location: Panama City, Fl Status: Offline Points: 265 |
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Especially mine! Winter has been rough on me! Understanding The concept of hook and rocker is not rocket science. No worse than rudder torque and how to manipulate it. Not always does hook need to be added to make ride changes a lot of times it is just a little sanding and polishing to increase rocker. It is not a black art like some would believe. Propellers and their dynamics are far more complicated yet is discussed nearly daily on this board. I am off to Short line lake (Pickos site) to take two sets and spend some time in both a new 2013 TXI and put some hours on a new 2013 200. Then back to the shop to put the finishing touches on a 71 Taylor Jet boat that I just fully stringer-ed and installed a composite transom in. Live the boating life and experience is gained! |
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Money Talks! BS Walks! and loose change rides the bus!!!
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BuffaloBFN
Grand Poobah Joined: June-24-2007 Location: Gainesville,GA Status: Offline Points: 6094 |
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Cars usually lean to port for some reason. Cheeseburgers?
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