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Author
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Topic: Keel Movement
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La chasse-galerie
unregistered
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posted February 18, 2005 10:58 PM
 
I know I have asked this question last year but by pure paranoia I will put it on the table again. Have any of you ever heard your keel move while lowered with the boat either stopped or at anchor? Mine seems to have some travel to it when the boat is not moving and no water pressure pushes on the keel.I have talked to the guys at CL about my concern and they have assured me that it is nothing to worry about unless the travel becomes severe. However, I was still wondering if any of you have ever had this... I have not decided if I will put the boat on the Travel-Lift this spring to inspect any further... IP: 66.130.29.203 |
Hyprstitch
Member
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posted February 19, 2005 01:06 AM
 
I've not noticed any movement on mine. But I've never listened for it. Sid IP: 64.12.117.13 |
SuperPiper
Member
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posted February 19, 2005 04:06 AM
La chasse-galerie:Yes, I know the sound. While lowering the keel on my 'Piper, there is usually some thumping just as it gets to 100% down. Some of the other sailors know their keels better, but, it is my understanding that the keel trunk is hollow & filled with foam. It could be expected to amplify any drumming noises. I don't know how solid or hollow the keel is. Nor do I know how much clearance there is between the keel and the trunk. I can't imagine that it is a machined fit. There has got to be some slop. So, is the Sandpiper keel considered self-tacking? Does it improve pointing to windward? IP: 69.156.2.195 |
CoolBreeze
Member
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posted February 19, 2005 07:45 AM
I have experienced the same thing. To the best of my knowledge it is nothing to worry about. There has to be a little space there to allow the keel to be retracted and lowered freely. SOLUTION: One solution I found was to crank up the keel maybe 2-4 turns. This really doesn't retract the keel enough to make much of a performance issue, but seems to hold it slightly tighter and therefore, no (or not as much) travel and noise. Has anyone else done this?
Not sure about the self tacking question, I'll leave that for a pro!! ------------------
Rob Belliveau
1976 Sandpiper 565
"Cool Breeze"
Halifax NS
Soon to be at DYC IP: 24.215.107.164 |
Eric
Member
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posted February 19, 2005 08:21 PM
If you hear a slight clunking when the keel is fully lowered I wouldn't worry about it, if it is a slight clunk. The keel is fully suspended on the jack screw, with about 4-6" of keel left remaining in the trunk. The trunk is naturally oversized a bit for the keel to move. If you feel the noise is more severe, then yes fully lower the keel on land and check the condition of the trailing edge of the keel. If you hear a noise when lowering, there could be a very slight deflection or bend in the bronze jack screw. At the point of travel in the screw where the deflection is, you will notice this noise. Forget about it.
Eric
 IP: 130.63.85.93 |
SuperPiper
Member
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posted February 20, 2005 03:56 AM
Eric:Gives us an update on the keel rebuild. What have you learned about the construction of this appendage? If you get a chance, could you measure the exact width (chord length) and thickness of the keel for me? It looks quite stout: efficient across a wide angle of attack, but inherently slow. IP: 65.93.72.245 |
2short S565
Member
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posted February 20, 2005 10:04 AM
Eric pretty well summed it up.
I like, he is in the process of doing, have had my keel completely out for rebuilding/fairing so I knew it inside and out (literaly).
The keel hangs from the screw and it will tap against the side of the trunk with subtle movements of the boat or water. This is perfectly normal.
I also agree with the comments about turning up a couple of turns to reduce the tapping. That does help if it bothers you. IP: 70.48.164.83 |
Eric
Member
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posted February 20, 2005 07:12 PM
The keel is still in my shop, although it has been completely sanded and ready for work. I will be getting at it in earnest very soon!
The keel is as you know lead. The fibreglass is molded in two pieces, and encapsulates the lead, joined along the seem. There are voids, but these are normal due to the nature of construction. There is a plate imbedded in the top where the screw goes through the fitting at the top. Cody tells me, the screw goes inside a tube, inside the lead casting.
I'll measure the keel for you Dennis, and post later. I'm not at home now. Hope this helps answer any questions.
EricIP: 130.63.85.93 |
Darcy
Member
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posted February 21, 2005 01:33 PM
Ours clunks a bit when we're at anchor or tied up at a dock. I love lying back in the cockpit and reading while at anchor. The periodic clunk can be a bit irritating. We crank up the keel 10 or 20 turns which seems to stop it. Just remeber to put the keel back down when you set sail. You'll make much better progress to windward if you do.Many centreboard boats do the same thing at anchor. Like the other guys, I don't think it's of any concern. D'Arcy IP: 65.92.98.171 |
Roger
Member
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posted February 21, 2005 09:56 PM
I have a daysailer II with a swing down cb. It too clunks at anchor or in slack water (no wind). Same solution, pull it up slightly so that is touches more of the inside of the cb trunk, and the bumping goes away. Consider this... there is WAY more pressure on the side of the cb and trunk when reaching that when it clunks at anchor! Its not causing your baby any problems.IP: 216.55.213.233 |
Windroos
Member
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posted April 01, 2005 10:40 PM
Hi EricWhen you write : Cody tells me, the screw goes inside a tube, inside the lead casting. Do you know if that tube has grooves so the shaft is turning all the way down the tube or there is only some threads on the top part. If so, how much thread do you imagine there are. Only want to figure how strong it might be. If we want to "warp" a foot of thread it will be much harder than a little 1 inche. Gotta keep my thread on the bronze shaft well lubricate in order to save the other part on the keel. Thanks. ------------------
John
Quebec city
Sandpiper 927 IP: 66.131.169.240 |
2short S565
Member
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posted April 02, 2005 09:54 AM
It is a piece of pipe or tubing with a smooth inside wall. It is about 1/4" larger in diameter than the diameter of the screw. Its purpose is only to serve as a guide thru the lead ballast (which I believe is in sections).
The pipe is actually slightly loose fitted thru the ballast (or was on mine at least)The actual threaded part is a seperate flanged nut that is screwed to the top of the keel. That one inch or so of thread in that nut is all that the screw normally contacts on the keel.
If the screw is slighlty bent, the bottom end of the screw will swing around and make contact with the inside of the tube, causing the keel to wobble as you turn the screw. IP: 70.48.166.149 |
Windroos
Member
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posted April 02, 2005 10:06 AM
He! thanks for the info very valuable.You seem to think that the lead ballast would be in" (which I believe is in sections). Do you think that a delaminated fiberglass kell would be in trouble? Mine is delaminated at the bottom back part in the center. I do not plan to repair it this year since it seems to be quite a job. Water entering between the fiber and the ballast should'nt worried me, what do you think. If Eric is reading this post, may we have your opinion please. ------------------
John
Quebec city
Sandpiper 927 IP: 66.131.169.240 |
