need help quick... MAST vibrations

[bristol321]

Having horrible vibrations in mast (as if you were tohold a rubber band taught between fingers and flick the middle)

Rigging is tight have forestay and aft 2 each at port and starboard just below spreader and then 1 each port and starboard to top of mast.

its a rather violent shake and I am concerned anyone else have this problem...suggest or preferrably know a fix?

[JohnRPollard]

A strong breeze can set up a mast vibration under certain circumstances. Does this occur while sailing underway, or at dock/anchor with sails furled? If you have roller furling, but no jib is set, sometimes the aluminum furler extrusion can induce a serious resonation in the rig. The quick fix is to put some tension on it by tying it off with a line led back to a cleat or the mast.

More info would be helpful.

[bristol321]

have a roller furler with the jib set. It only occurs at dock and anchor never while sailing. have tried tightening the two spreader bar stays that are forward no luck.

[retclt]

Could it be resonating through the mast from something underneath? Maybe something to do with the keel or Shaft/cutlass bearing?

Edit . . . Scratch this comment . . . thought you were in motion.

[bristol321]

definitely the mast nothing from underneath I can see the mast vibrating. It moves 2-3 inches roughly halfway up the mast and that is vibrating/shaking the boat

[bfdtpkt]

I'd axe a qualified "rigging" tech and maybe even have him check it out....

[Idiens]

If its at the dock, with the jib roller furled, I bet on the furled jib creating the vibration. A bungy cord to the pullpit usually fixes it.

[Wayne25]

If it's moving 2-3 inches, I can't imagine its doing the rigging or your boat any good. I would loosen the rigging to just more than slack, plumb the mast and re-tune the rig or have a rigger do it if you don't know how.

[TThomsen]

How big a boat and is the mast deck or keel stepped

[sailingdog]

I would definitely check the roller furling jib for being one possible source. You should also contact a rigger, since that type of vibration can lead to the aluminum mast fatiguing... and that becomes a very expensive repair if the mast fails.