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Edavys2018
Last seen: 3 months 2 weeks ago
Joined: 1/31/18
Posts: 3
How tight should my shrouds be on a 36' tall rig?

I have owned this boat for 1,1/2 years and love it!  However I'm getting too much vibration down the mast in winds over 15 knots.  Also I have never owned a sailboat that was rigged this tightly.  There is literally no give in my shrouds.  Is this tight rigging correct for a tall rig?  Or should I ease my shrouds?

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pkeyser
Last seen: 2 hours 9 min ago
Joined: 5/18/13
Posts: 444

Do you get a "mast pumping" that transmits through the boat or more a humming vibration? Vibration can also occur from taught halyards and/or tension on the topping lift. We have a topping lift and a rgid boom vang. We really don't need the topping lift but it was on the boat and it oftem hums when it's under moderate tension. No problem when tension is eased. Our internal halyards can also vibrate because there's a length of exposed line between the turning blocks at the mast base and where they exit the mast. Loosening up tension will relieve that too.

Mast pumping can be caused by improper shroud and stay tension. I'm not a standing rigging expert, and I don't own a tension tool,  so I tighten by feel and sight. First, sight straight up the leading edge of the mast. It should be perfectly straight without side to side bend. Then sight up the sides of the mast. There should be no forward or aft bend.  If there is any bend, pull on each shroud and observe how the mast reacts. (Also observe how tugging on the side stays impacts mast straightness). Assuming the mast is without bend, the shrouds should deflect about 1 1/2-2 inches when pulling inward about 7-8 feet up from the deck. I probably apply ~40 pounds of force. Apply the same force to all four shrouds and see if any turnbuckle adjustment might be needed. The stays should have more tension than the shrouds so will deflect less with the same force. Your leeward shrouds should be slightly slack when sailing close hauled. If they are still under moderate tension, they should be loosened. You should also sight up the mast when underway and it should remain straight if everything is properly tensioned.

Tuning the rig should be done while the boat is in the water, not on the hard.

I'm sure others will have a more scientific and accurate approach

 

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Paul & Wendy Keyser
"First Light"
Newburyport MA/Rye NH
2005 C36 MKII #2257
Wing, M35B

pierview
Last seen: 16 hours 43 min ago
Joined: 9/27/09
Posts: 491

I'm far from an expert on rigging tension, but we had a rigger do a presentation at our club.

His said the shrouds  on the leeward side should be somewhat loose when sailing but not "floppy" loose. When you say you have"no give" I assume you mean when you are sailing.

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Chuck Parker
HelenRita 2072 Mk II
2002 Tall Rig - Winged Keel
Atlantic Highlands, NJ

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pkeyser
Last seen: 2 hours 9 min ago
Joined: 5/18/13
Posts: 444

Chuck-
That's a good way to describe it: leeward shrouds should be loose, but not floppy loose; virtually free of tension while sailing up wind with modest wind.

--

Paul & Wendy Keyser
"First Light"
Newburyport MA/Rye NH
2005 C36 MKII #2257
Wing, M35B

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