why ski boats use opposite rotation
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URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=7342
Printed Date: December-23-2024 at 1:00pm
Topic: why ski boats use opposite rotation
Posted By: eric lavine
Subject: why ski boats use opposite rotation
Date Posted: July-03-2007 at 7:04pm
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I was told by a very reliable source why ski boats use opposite rotion engines and props, I truly dont know why but was told it was for reversing, the boat has a tendency to pull to the drivers side for docking because of the prop,
?????? ------------- "the things you own will start to own you" |
Replies:
Posted By: nates78ski
Date Posted: July-03-2007 at 7:06pm
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Doesn't it pull to the port side though?
Nate ------------- Nathan http://correctcraftfan.com/diaries/details.asp?ID=1463&sort=&pagenum=3&yrstart=1978&yrend=1978" rel="nofollow - My '78 Ski Nautique <a href="http://photobucket.com/Nates78ski" rel="nofoll |
Posted By: Hollywood
Date Posted: July-03-2007 at 7:14pm
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there are ski boats that go both ways ------------- |
Posted By: eric lavine
Date Posted: July-03-2007 at 8:14pm
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just passing on what i was told...it makes sense, in general it was also meant for all single screw boats, dont want to start controversey, and he said especially ski boats ------------- "the things you own will start to own you" |
Posted By: Darrel
Date Posted: July-03-2007 at 9:10pm
there are skiers that go both ways, not that theres anything wrong with that.
to counteract the weight of the driver. |
Posted By: nates78ski
Date Posted: July-03-2007 at 9:58pm
Maybe your boat, but mine's straight as an arrow
Nate ------------- Nathan http://correctcraftfan.com/diaries/details.asp?ID=1463&sort=&pagenum=3&yrstart=1978&yrend=1978" rel="nofollow - My '78 Ski Nautique <a href="http://photobucket.com/Nates78ski" rel="nofoll |
Hollywood wrote:Posted By: 75 Tique
Date Posted: July-04-2007 at 2:03am
I'm pretty sure this one doesn't go both ways.
 ------------- _____________ “So, how was your weekend?” “Well, let me see…sun burn, stiff neck, screwed up back, assorted aches and pains….yup, my weekend was great, thanks for asking.” |
Posted By: eric lavine
Date Posted: July-04-2007 at 12:21pm
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what i dont understand about the counteracting the weight of the driver is, 95 % of the time you have a observer next to you to equal the weight ------------- "the things you own will start to own you" |
Posted By: Tomski
Date Posted: July-04-2007 at 2:24pm
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Exactly what I have always wondered Eric. That point applies especially to a ski boat since, as you say, it is going to have a third in almost all the time.
I know that older volvo drives will run either way, what about mercs? I'm going to test it this weekend by getting her lit up and then moving to the observer seat to see what happens - obviously I'll find a quiet bit lake to do it on! ------------- Easily Parted From Money |
Posted By: eric lavine
Date Posted: July-04-2007 at 4:48pm
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with the mercs and volvos you can turn the drive and pull your self into the dock, try it out, keep the rudder straight and throw it into reverse and see what happens....will it pull to the starboard or not...that is the question ------------- "the things you own will start to own you" |
Posted By: boat dr
Date Posted: July-05-2007 at 12:46am
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Eric, you have too much idle time on your hands.Thinking is not one of your better attributes,surely there are more dire issues that your superior mind should be dealing with.
As to global warming or alternative energy , you know things that make a difference in our quality of life............boat dr what about Green Lake ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: reidp
Date Posted: July-05-2007 at 11:32am
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I hate to say it Eric, but you may need to go back to that source. More specific than the engine rotation, is that a right hand prop backs to Port or the passenger side. So a RR engine running thru a straight 1:1 gear will turn a RH prop and will back generally to Port. Similarly in terms of backing, a Std Rot engine, running thru a reduction gear which spins the output shaft the opposite direction (I know you're more aware of that than anyone) turns a RH prop and also backs to Port. So in essence, RH props back to Port and LH props back to starboard. The answer I'm still in search of, and I believe we batted it around somewhat before, is why historically most single engine inboards have turned RH props which necessitated RR engines when using 1:1, and was it because helms were on the starboard side, AND then why were helms on the starboard side to begin with. The chicken or the egg......... ------------- ReidP /diaries/details.asp?ID=231&yrstart=1971&yrend=1975 - 1973 Mustang |
Posted By: Nautique2001
Date Posted: July-05-2007 at 1:00pm
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Gay Craft, isn't that the name of Hollywood's boat?
Ken ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1052&sort=&pagenum=4&yrstart=1986&yrend=1990" rel="nofollow - Nautique 2001 |
Posted By: Darrel
Date Posted: July-05-2007 at 8:39pm
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The chicken or the egg.........
What weighs more, Nicole Ritchie or her unborn baby? |
Posted By: boat dr
Date Posted: July-05-2007 at 8:57pm
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The chicken came first, then KFC....
Who the hell is Nicole Ritchie????? boat dr ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: eric lavine
Date Posted: July-06-2007 at 12:23am
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the quest continues......
------------- "the things you own will start to own you" |
Posted By: eric lavine
Date Posted: July-06-2007 at 10:02am
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Boat doc, I cant believe this countries Media failed and you dont know who nicole ritchie is, have you heard of a church girl named Paris Hilton? ------------- "the things you own will start to own you" |
Posted By: stang72
Date Posted: July-11-2007 at 3:28am
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I think BKH had some points nailed down about the rr turning engine. One as I recall was...when picking up a skier(drivers side)and hitting reverse...the stern swings out away from the skier...safety thing I guess.
------------- stang Face plants are not that funny when it's you face! http://www.correctcraftfan.com/diaries/images/3720/photo1.jpg" rel="nofollow - The Super Air |
Posted By: Tomski
Date Posted: July-11-2007 at 7:30am
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Ah, Ritchie and Hilton, two of Britain's finest exports - you are welcome to them!
Anyway tested the counteracting torque theory, sort of, at the weekend and at speed (between 35 and 40) with just me in the boat on glass like water moving over to the observer seat made no difference at all that I could tell. It does kick to port in reverse, looking at the prop I imagine that it will paddle wheel significantly at low speed in reverse. ------------- Easily Parted From Money |
Posted By: eric lavine
Date Posted: July-11-2007 at 9:16am
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one of the seven wonders of the world,
Ive made it my mission to find out why ------------- "the things you own will start to own you" |
Posted By: 8122pbrainard
Date Posted: July-11-2007 at 9:57am
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Ok, We need to start with the early automotive engine that was marinized for boats.
They hand cranked clockwise because most people are right handed and it's easier for them to crank clockwise. Next you take that auto engine and marinize it with the flywheel forward (with large flywheels, they would sit lower in the bilge with the flywheel forward)and that engine became the marine RH. The next step brought us into the V8's. These early V8's were also mounted flywheel forward to get them lower in the bilge plus by this time all the prop manufacturers we making RH props. The problem really started when these early V8's started snapping cranks because all the power of the engine was taken off the weaker PTO end of the engine. To solve this the auto engines where marinized with the flywheels aft but since all the props were RH, the auto engines needed to be built reverse rotation. There are a few odd balls out there like the 225 c.i. V6 that wasn't built reverse and needed a LH prop as well as a couple years when the marine engine manufacturers decided it was cheaper to use a standard rotation auto engine and let the prop guys tool up for LH props. Of coarse now with a few gears behind the engine we have standard rotation engines running RH props! ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: eric lavine
Date Posted: July-11-2007 at 10:34am
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nowadays transmissions are manufactured to spin full power forward or full power reverse, which means you can use a normal rotation engine and spin a left or a right hand prop.
im rebuilding 2 identical transmissions that go behind 2 normal rotation engines but, it uses a left and a right prop. A borg warner or even a PCM must use forward as forward, opposite rotation engines are slowly fading away because of this ------------- "the things you own will start to own you" |
Posted By: Riley
Date Posted: July-11-2007 at 4:30pm
| I don't think there is a good explanation. The 1st two inboards I had were RH engines and they pulled to port in reverse. The 2nd two were LH engines and they pulled to starboard in reverse. I think LH engines with a starboard helm are easier to handle. |