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10688Re: [SabreSailboat] rigging problem, and shuddering rudder

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  • Dave Lochner
    Jun 1, 2007

      In my earlier email, I didn't mean that the mast was no longer useable, rather, that continuing to try and tune it was hopeless, you needed to start from scratch. Any bow in the mast from being stored horizontally, usually comes out quickly once the mast is vertical. 

      If I'm understanding you correctly, the problem is not with the lowers, but the uppers. Look at the turnbuckles, my guess is that the port turnbuckle is tightened up more than the starboard turnbuckle, effectively making the port shroud shorter than the starboard shroud. This would exert pressure on the top of the mast, causing it to fall off to port and pushing the middle of the mast to starboard. This can happen even with equal tension on the shrouds. The solution is to back everything off and give the shrouds a shake or two. Then start over again, tightening equally and slowly. One turn on one side, check the mast to make certain its still in column, then one turn on the other side. Towards the end of the process you may want to do a half turn, check, then another half turn. Keep this up, until you have the right amount of tension (10-15% or so of the breaking strength). The lowers should have just enough tension to keep the rig from falling over, roughly had tight. Forestay and backstay should also be just hand tight, enough to keep the mast standing, but not enough to cause the mast to bend.

      After you get the uppers properly tensioned then it time to do the forward lowers (same process, slow and even) and finally the aft lowers.

      While you're lying on your back sighting up the mast, experiment a bit by pulling on the shrouds and watching the mast bend, you'll get a feel for how little tension it takes to get things out of whack. 

      Selden Masts has a guide that will tell you more than you want to know. You can download it

      I'm not sure what kind of vibration/shudder your getting on the rudder. 


      On Jun 1, 2007, at 8:20 AM, sid wax wrote:

      Don't think the bow is in the mast, because, then the side towards the bow would be loose, not the other side.  I did remove the bottom plate. There was just one screw, which of course sheered off, and I had to drill another hole.  I did that on the other side, and the mast was sort of a sloppy fit.  Could that amount of misadjustment cause the problem?  Also, if a bow in the mast is the problem, then could it be because they left yhe mast supported all winter just from the two ends?
      I'm actually more concerned now with the steering vibration.
      Dave Lochner <davelochner@mac.com> wrote:

      Once a mast gets any kind of bow in it, its ! hopeless to try and get it out.

      Do as Pete suggests, loosen everything, shake it a bit, and let the mast recover and get sort of straight. 

      Then slowly start over again, beginning with the uppers. Tighten the turnbuckles to a loose hand tight and make sure you're still in column. Then tighten one side one turn, then the other side one turn.  Work slowly and check both the tension and the straightness of the mast after every adjustment.


      On Jun 1, 2007, at 12:37 AM, sid wax wrote:

      The other 4 stays all had plenty of room for adjustment,  But the 2 I mentioned were really far out of whack.  As I recall, I didn't try adjusting the uppers, but any adjustment on the other lowers seem like they would either increase the ! bow or further slacken the port lower.
      One thing I did notice, though.  I am not sure whether the PO had a turnbuckle boot on the backstay, but with a boot installed, it interfered with the traveler, which indicates that somehow the rig should be further aft.   I tightened the backstay, but that would even further stretch the forward starboard lower, and that one is so slackened that it is is almost coming apart, and is still tight.
      I guess I depended on the riggers to have a clue how to set up the rig.  I'll have to start from scratch, loosen the lowers and get the uppers straightened out first.&! nbsp; The procedure ought to include using the halyards to check the rig for plumb, and then trying to adjust the aft lowers, then the forward lowers.  I'll need more advice on fine tuning, but the rig is so far off now, that I am concerned there may be some more serious problem.
      The steering is another issue, and everything I have read says that you really have to tighten the cable, but I wonder if it could be too tight, and binding someplace, and/or maybe it just needs proper lubrication.  The yard guy said he had opened it up to examine the system, but presumably he just gave it a quick look, and I will have to open it up myself and go through the full Edson maintenance procedure.  But boat goes in this week, anyway.

      Carter Brey <cbrey@attglobal.net> wrote:

      what about slackening the port upper and tightening the starboard upper?

      What about the starboard aft lower and port forward lower? Can they be
      respectively loosened and tightened?


      sid wax wrote:
      > I had my mast stepped today, and a few of the stays seem to be messed
      > up. There seems to be a bit of bow to starboard, and yet the
      > starboard forward lower is as loose as it can be, and the port aft
      > lower is as tight as it can be (actually, the latter is a bit off
      > center, and I could probably get another 1/2" out of it, but I don't
      > think that would do it.
      > My first thought as to a culprit was the mast step, but the backstay
      > seems good and solid (The headstay is non-adjustable roller
      > furling). Another thought was that since I had to remove the bottom
      > casting and of course drill new holes, so that the casting may have
      > moved, and the mast may be askew. I do not know if this problem
      > existed last season, before the mast was pulled, but I do know the
      > boat was quite slow last year.
      > Any help? Boat goes in the water tomorrow. Is there any reason to
      > delay that?
      > Also, I've had the problem of a shuddering in the rudder. A rigger
      > opened up the pedestal and told me the steering was not the culprit,
      > and thought it was in the rudder bearing. However, it doesn't feel
      > like a bearing thing, and besides, since they repaced bhe rusty
      > clamps on the cable the shuddering seems more pronounced. Any clues?
      > Sid

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