Rigging vibrations

[wcrann]

Hi fellow sailors,

I have a 1988 Catalina 34, hull 660 and was wondering if any other 34 owners have experienced the rigging shaking or vibrating while at the dock... When the wind is up over 10 knots the rigging starts to vibrate and you can feel it throughout the boat. Is it a tensioning problem, if so does anyone have the correct tensioning specs... I'm concerned about the long term effects on the rigging and hull.

Cheers,

Wayne

[Ron Hill]

WAYNE : The rigging on a C34 should be fairly taunt and should not vibrate in the wind. 
What will happen is the halyards will rattle inside the mast when the wind blows.  Re tension and that will hold down the noise alittle. 

[David Sanner]

Sounds like what you have going on is your mast is pumping.

If the rig tension is set a certain way the vibrations in the shrouds from
the wind can become harmonic and you'll feel a pumping in the boat.

It's hard (if not impossible) to completely remove all the harmonics
but you should be able to improve things quite a bit.

Usually the aft lowers are not as tight as the forward lowers.
(If they are the same they are more likely to setup a harmonic)

Here's a thread that might help
http://c34.org/bbs/index.php?topic=1417.0

[Stu Jackson]

In addition, go here:

http://www.c34.org/faq-pages/faq-mast-pumping.html

I heartily recommend that folks go to FAQs on the main hoome page (www.c34.org).

The FAQs on THIS website are NOT how to use the website, but ARE about the BOAT!!!!

[tstrand]

After many windy nights at anchor, we've learned to use rigging sounds as an in-cabin wind gauge. There's the ten-knot hum, the fifteen knot mast pumping, the twenty-knot whistle, and something that starts at around thirty knots that I'd describe as a shriek. All boats are different, of course, so you'll have to calibrate your own.

Tim

[Bill Jenks]

I had the same problem with my 2000 C34. I asked Brian Toss - a highly respected rigger in Washington - and his answer was to hoist a fender using a jib halyard (attatch a down haul to the bottom of the fender) to a point a few feet above the spreaders. He said I may have to play with the height a bit to get it to work. I tried it and it works. The fender disturber the airflow around the mast enough to keep any harmonic vibration from getting started. I looks a bit funny but it works. He also told me to make sure my rig was adjusted properly for sailing and then do not change the adjustment to get rid of the vibration.

Hope it helps

[Gene Regan]

I have found that wraping the halyards around the mast and securing them to the deck at the base of the mast eliminates 90% of the problem. I found this info on our site and applied it and it made a diffenence.

[Jeff_McKinney]

Gene's suggestion also stops that annoying "halyard slap" that everyone hates (especially any live-aboards in the area).

Tim: I think that 20 Kt whistle & 30 Kt shriek is the wind blowing across the luff slot in the mast while docked At least that seems to be the case with me.