Two speed transmission
Printed From: CorrectCraftFan.com
Category: General Correct Craft Discussion
Forum Name: Off Topic
Forum Discription: Anything non-Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=21016
Printed Date: January-11-2025 at 11:02am
Topic: Two speed transmission
Posted By: sweet77
Subject: Two speed transmission
Date Posted: March-23-2011 at 12:52am
Was thinking today how to lower rpms in a CC when wanting to cruise around and not pulling anything. just hanging on the lake or river two speed or some kind of gear vendor overdrive setup .......could be way off base or just plain dumb but its just what i think about  ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5528&sort=&pagenum=1" rel="nofollow - 76 Nautique "If you do what you always did,You'll get what you always got!" "An empty wagon makes t |
Replies:
Posted By: eric lavine
Date Posted: March-23-2011 at 8:57am
|
ZF offers a 2 speed, a few other companies out there have tried it in the larger boat market...actually, on the ZFs or twin disc transmissions they offer trolling valves which allows the clutches to slip at lower rpms, fishing boats utilize them often to get slower trolling speeds. back in the early days though they would power up and forget to dis-engage the valve and would smoke the trans...now there are failsafe features that wont let you power up until it is dis-engaged.
btw, you can slip clutches at low rpms and it will not comprimise the clutches, they rely on oil shear between them, but with a trolling valve you can virtually spin the prop as slow as you would like, I know these ski boats are "fast" in the no wake zone and create a wake and you have to pull in and out of gear to keep the boat speed to a minimum ------------- "the things you own will start to own you" |
Posted By: Luchog
Date Posted: March-23-2011 at 10:46am
|
you could get a larger pitched prop but to the cost of loosing pulling power.
You could have a nice set of paddles onboard though... ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique Commander 351W |
Posted By: Bri892001
Date Posted: March-24-2011 at 3:34pm
|
Actually, MB Sports has a two speed transmission. They use it for a different reason though. They used it to get a heavily loaded/ballasted boat out of the hole more quickly. It looks pretty cool. If you watch the video, the driver does a quick "slight of hand" with the throttle to unload the transmission while he shifts it:
http://www.mbsports.net/accessory_view.asp?accessory=transmission - MB Sports Two Speed |
Posted By: Luchog
Date Posted: March-24-2011 at 3:59pm
actually he does this because he thinks it looks good...  ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique Commander 351W |
Bri892001 wrote:Posted By: mdvalant
Date Posted: March-24-2011 at 4:45pm
|
I wanna chat about this 2-speed tranny. Would this be sweet in the show ski world? Will other makers start trying this out? What are your guys' thoughts?
------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: Bri892001
Date Posted: March-24-2011 at 5:14pm
|
I stumbled across that MB Sports video at least a year ago. I'm not sure how long they've had it or how it works. Like, does it need a torque converter?
I kind of figured one of those Dual Clutch Auto-manual type things, that VW has might work, although expensive. With a boat, you don't really have time to clutch and shift before you'd be loosing a lot of momentum. Also, I feel like a torque converter would give up too much horsepower. |
Posted By: 62 wood
Date Posted: March-24-2011 at 6:16pm
|
I came across an old homemade plywood boat years ago that had a Ford 6 banger with the stock three speed trans in place. The boat was small "cruiser"..maybe 17-18 foot. It was not sea-worthy, but I always wondered how it worked? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1117&sort=&pagenum=6" rel="nofollow - 64 American Skier 62 Classic.. 73 Ski Nautique |
Posted By: hotboat
Date Posted: March-24-2011 at 7:28pm
|
Near as I can tell all you could ever do is increase the holeshot with more gears but you get into cavitation and the water makes a nice torque converter. hp torque and amount of drag are all that can be changed to reduce rpm at a given speed. ------------- Brian |
Posted By: eric lavine
Date Posted: March-25-2011 at 10:18am
|
with the technology available today, i think it would be more feasible to go after a a hydraulically controlled variable pitch prop with a govonor on it. but if anything a piggyback gear vendor overdrive/underdrive behind the trans too would work ------------- "the things you own will start to own you" |
Posted By: eric lavine
Date Posted: March-25-2011 at 10:24am
|
man the times i couldve got away with "I had to replace the torque converter too"
actually, you really could utilize just a converter, and just like overdrive on a auto, you hit a certain speed and lock the converter at a true 1:1...thats all overdrive on a car is, a torque converter is just a means of transfering power but is only about 95% efficient until you lock it up into a 1:1....thus that was the day the ratings for mpg's went higher on an automatic transmission back in the day because of the true 1:1 lock up. the button on your gear shifter sends a signal to a solenoid and fluid will go to a clutch plate in the converter and lock it ------------- "the things you own will start to own you" |
Posted By: peter1234
Date Posted: March-25-2011 at 11:40am
|
how fun would a m22 muncie be ------------- former skylark owner now a formula but I cant let this place go |
Posted By: skutsch
Date Posted: March-25-2011 at 1:28pm
Standard propeller technology in the aviation industry. I like the idea. Boat propellers seem to be much more sophisticated/complicated but given enough engineering time applied, I bet someone could solve the riddle. Lots of stuff to work out with it being underwater. Again doesn't sound insurmountable, but VERY expensive. ------------- Our http://www.correctcraftfan.com/diaries/details.asp?ID=4669" rel="nofollow - 98 Sport Nautique My Dad's 63 Ski N |
Posted By: BFNSport
Date Posted: March-25-2011 at 10:33pm
|
Out boards have shifting props ....
My Grand dad made a manual shift boat out of a Crosly back when my dad was a kid.Dad said it was one of the funniest things he has ever seen. Just about sent grandma over the bow when he tried to shift. After that they just used 3rd gear..LOL |
Posted By: eric lavine
Date Posted: March-26-2011 at 10:57am
|
The mastercrafts have the abilty to use a trolling valve because of the transmissions they use "HSW 630's", that would probably be the most feasible choice to slow the boat down in no wake zones, but prop technology is right there and there really seems to be no need for 2 speeds in a ski boat. Oh, it would be a nice addition or option, but, really not needed ------------- "the things you own will start to own you" |
Posted By: Luchog
Date Posted: March-26-2011 at 1:52pm
|
I think of boats like women,the less buttons I have to press to make them work the more I like them. Keep them simple. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=2095" rel="nofollow - 1980 Ski Nautique Commander 351W |
Posted By: eric lavine
Date Posted: March-26-2011 at 6:30pm
|
Luch, just make sure you hit the right button ------------- "the things you own will start to own you" |