pitot tube question?
Printed From: CorrectCraftFan.com
Category: General Correct Craft Discussion
Forum Name: General Discussion
Forum Discription: Anything Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=12833
Printed Date: January-11-2025 at 9:48am
Topic: pitot tube question?
Posted By: 62 wood
Subject: pitot tube question?
Date Posted: February-10-2009 at 12:50am
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I understand the larger tubes (just above the platform) are stabilizers for the speedos, on http://www.correctcraftfan.com/diaries/details.asp?ID=146&sort=&pagenum=9&yrstart=1970&yrend=1973 - this 72 SN ?
I see the speedo tubing runs into them, but how do they actually work? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1117&sort=&pagenum=6" rel="nofollow - 64 American Skier 62 Classic.. 73 Ski Nautique |
Replies:
Posted By: critter
Date Posted: February-10-2009 at 1:20am
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I understand that they are equallizers and the water from the pitot displaces the air in the equallizer. This causes pressure at the speedo and results in needle movement.
------------- 1980 Ski Nautique 1966 Barracuda |
Posted By: Gary S
Date Posted: February-10-2009 at 1:55am
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Steve , they can also be mounted anywhere ,mine is mounted on the stringer behind the toe board ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: 8122pbrainard
Date Posted: February-10-2009 at 10:02am
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Steve,
They can also be called pulsation dampeners. They smooth out the air pressure coming from the pickup so you don't get as much needle bounce on the speedo. ------------- /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: TRBenj
Date Posted: February-10-2009 at 11:33am
True- but you want them to be as close to vertical as possible. ------------- |
Gary S wrote:Posted By: DrCC
Date Posted: February-10-2009 at 10:21pm
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They can also be referred to as Ballast tubes.
They (CC) moved them to the inside of the transom around 1975 or 1976. ____________ http://i54.photobucket.com/albums/g96/DrCC-74/Nautiqueatpark-01.jpg - '74 Ski Nautique http://i54.photobucket.com/albums/g96/DrCC-74/Jess73-01.jpg - '73 Ski Nautique http://i54.photobucket.com/albums/g96/DrCC-74/ol66er.jpg - '66 Mustang http://i54.photobucket.com/albums/g96/DrCC-74/88MustangGT-500pixel.jpg - '88 Mustang |
Posted By: bkhallpass
Date Posted: February-10-2009 at 11:46pm
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Good info. I always called them "those speedo things on the back of the boat."
BKH ------------- Livin' the Dream |
Posted By: 62 wood
Date Posted: February-11-2009 at 12:03am
 me too Brian..
Does anyone know, Do all speedos use them, or are they just for the boats requiring more accurate readings? (ie: tournement ski boats) ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1117&sort=&pagenum=6" rel="nofollow - 64 American Skier 62 Classic.. 73 Ski Nautique |
Posted By: sethro
Date Posted: February-11-2009 at 5:09pm
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I don't know about all boats, but I did a bunch of trouble shooting with pitot driven speedos on an 85 MasterCraft last summer. I learned that the tubes (I was calling them ballast tubes) didn't seem to have any effect on the readout. I didn't see a difference in anything...bouncing or time to register the speed.
I ended up keeping them on the boat just because and replaced the pitots with the new venturi style from skidim.com My friend's 84 MasterCraft has never had the tubes and his speedos function just fine. |
Posted By: Tellarico
Date Posted: February-12-2009 at 7:58pm
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When my speedos were out being serviced water ran out of the end of the tube that attaches to the speedo. I read above "air pressure" where is my problem if I have water instead of air? have not run them since. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=3510 - Restoring 1975 Ski |
Posted By: 8122pbrainard
Date Posted: February-12-2009 at 9:53pm
Paul, Water ran out of them BEFORE you sent them out for restoration, correct? Air pressure is created by the water pushing in at the pickup. Inside the speedo is a bellows that changes the air pressure into a mechanical needle movement. The bellows are known to break. When this happens, the bellows won't hold the air pressure so there's nothing to hold the water back. Now, the water makes it all the way up to the speedo and then usually pis** on your legs!!!! ------------- /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: 65 'cuda
Date Posted: February-12-2009 at 11:11pm
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Last spring after having the speedometer out,I left the line off the back. Running across the lake during first trip I noticed the water pissing on my legs. I was amazed how much pressure was there, I had a difficult time holding back the water with my thumb on the way back to the dock. Be sure to blow all the water back out of the tubing before hooking back up the tubing. ------------- Gary http://www.correctcraftfan.com/diaries/details.asp?ID=941" rel="nofollow - 1965 Barracuda SS |
Posted By: Tellarico
Date Posted: February-13-2009 at 1:02pm
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Thanks Pete, It was before I sent the speedos out and during the time they were out. I will blow the water out before I hook them up again. My motor should be back in after a rebuild next week and I will gewt to run it and check it out. Paul ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=3510 - Restoring 1975 Ski |