Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 29-10-2009, 08:31   #1
Senior Cruiser
 
Ocean Girl's Avatar

Cruisers Forum Supporter

Join Date: Jun 2009
Location: In transit ( Texas to wherever the wind blows us)
Boat: Pacific Seacraft a Crealock 34
Posts: 4,115
Images: 2
Mast Pumping / Vibrating

In the slip during a wind gust my mast vibrates. I have tuned the rig, my friend the rigger has re-tuned the rig..?? The vibration is enough to shake my windex. I have checked all the tangs and chainplates, but will again when I have the time (I work long hours - ugh).

It did not pump before I replaced the bowsprit, which is very odd considering the bowsprit was rotten and the forestay had no support. The new bowsprit is a replica, except it is a bit thicker and longer, the j-measurement has not changed.

Tune the rig again? Should I put in a little more rake?

Thanks,
Erika
__________________

__________________
Ocean Girl is offline   Reply With Quote
Old 29-10-2009, 08:46   #2
Registered User
 
DaveC's Avatar

Join Date: Oct 2009
Location: Melbourne, Florida
Boat: Belliure Endurance 35
Posts: 124
Send a message via Yahoo to DaveC
Too tight?

My first thought would be maybe the rig is a little too tight at the top compared with the lower shrouds? I tend to keep all mine (uppers and lowers) a little loose since I'm not racing (not flopping around loose, but not real tight). Makes it easier on everything. If you're going to be in a rolling sea then maybe tighten it a bit...

I'm not an expert rig-tuner, however.

-David
__________________

__________________
DaveC is offline   Reply With Quote
Old 29-10-2009, 08:55   #3
Senior Cruiser
 
Sailmonkey's Avatar

Cruisers Forum Supporter

Join Date: Sep 2009
Location: Houston
Boat: '76 Allied Seawind II, 32'
Posts: 5,780
Mine does the same thing, shakes the whole boat in a breeze at the slip. Our boats are rigged the same and I have not found what's wrong either.
__________________
Sailmonkey is offline   Reply With Quote
Old 29-10-2009, 09:01   #4
Registered User

Join Date: Sep 2009
Location: Baltimore, USA
Boat: Irwin Citation 39 'Chesagansett'
Posts: 159
It might be as simple as that the new bow sprit is elastic, while the rotten one would have damped down the vibration.
__________________
steve_hendry is offline   Reply With Quote
Old 29-10-2009, 09:03   #5
CF Adviser
 
Bash's Avatar

Cruisers Forum Supporter

Join Date: Dec 2008
Location: sausalito
Boat: 14 meter sloop
Posts: 7,260
given that this problem didn't exist with the old sprit, the first thing I'd recommend checking is the dolphin striker. the source of your problems may be the longer sprit, which means the tension on the stricker is critical.
__________________
cruising is entirely about showing up--in boat shoes.
Bash is offline   Reply With Quote
Old 29-10-2009, 09:15   #6
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,583
Images: 240
Damping or muting:
Was the old sprit so rotten that is couldn’t transmit vibrations to the boat, or hold enough tension for the rig to vibrate?
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 29-10-2009, 09:18   #7
Registered User

Join Date: Oct 2009
Location: Rowayton, Ct.
Boat: Cambria 46, Starlight
Posts: 139
The rig on my old boat, a Contessa 35, sometimes vibrated in a breeze while anchored or moored as well. Often I found that simply adding or letting off the hydraulic backstay pressure helped. Sometimes, it is just a harmonic that can be eliminated with a little change like that.
__________________
HHNTR111 is offline   Reply With Quote
Old 29-10-2009, 09:19   #8
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
Do you have an adjustable backstay. If so, loosen it up during wind storms in port.

Mine will actually sing and I can change it's tune using the hydraulic back stay.

Also a topping lift and halyards can affect the rig. Just experiment with your lines until you get the results you want or can live with............_/)
__________________
Faithful are the Wounds of a Friend, but the Kisses of the Enemy are Deceitful! ........
A nation of sheep breeds a government of wolves!

Unprepared boaters, end up as floatsum!.......
delmarrey is offline   Reply With Quote
Old 29-10-2009, 09:21   #9
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,365
It's really not uncommon for a boat to have the mast start harmonic vibrations under certain conditions, is the problem more mast pumping or more just rigging vibration? Try putting some bungee cords accross the shrouds and uppers tieing all three together on both sides about 7-8 ft up. If the mast pumps, buy a nylon strop, put it around the mast and pass a halyard (spinnaker?) down through it and then forward to the front of the boat... thus supporting the center section of the mast. also, if the prevailing winds do this, have you tried just turning the boat around in the slip?
__________________
Cheechako is offline   Reply With Quote
Old 29-10-2009, 09:30   #10
Registered User
 
sailvayu's Avatar

Join Date: Mar 2006
Location: Fort Myers FL
Boat: Irwin 40
Posts: 878
Do you have a roller furling jib up?

Wayne Canning, AMS
__________________
sailvayu is offline   Reply With Quote
Old 29-10-2009, 10:34   #11
Senior Cruiser
 
Ocean Girl's Avatar

Cruisers Forum Supporter

Join Date: Jun 2009
Location: In transit ( Texas to wherever the wind blows us)
Boat: Pacific Seacraft a Crealock 34
Posts: 4,115
Images: 2
Thanks for the input, I am sorry but I have to run to work! but did want to quickly add that her bowsprit is the same but heavier, no roller furling. I will try to re tune.
She isn't just humming, she is pumping. It moves the whole boat and I worry about the stress that is doing to the rig fittings. One thing I didn't check was the compression post...gulp, if it is soft that could be why she wont stay tuned. Late for work, thanks for the replies
Cheers,
Erika
__________________
Ocean Girl is offline   Reply With Quote
Old 29-10-2009, 10:48   #12
RTB
Registered User
 
RTB's Avatar

Join Date: Nov 2008
Location: Home port Kemah, TX Currently in Brunswick Georgia
Boat: Hunter 36
Posts: 1,509
Images: 2
Mine does the same thing. You may be referring to our little storm last Monday....winds 50+ according to our marina manager, and I was on my boat wondering if my new docklines would hold!
__________________
RTB is offline   Reply With Quote
Old 29-10-2009, 13:03   #13
Eternal Member
 
imagine2frolic's Avatar

Join Date: Feb 2008
Location: Las Brisas Panama AGAIN!
Boat: Simpson, Catamaran, 46ft. IMAGINE
Posts: 4,508
Images: 123
I found releiving the tension on the mainsheet relieved me of the pumping. Something is too tight somewhere.........i2f
__________________
SAILING is not always a slick magazine cover!
BORROWED..No single one of is as smart as all of us!
http://sailingwithcancer.blogspot.com/
imagine2frolic is offline   Reply With Quote
Old 29-10-2009, 14:46   #14
Registered User
 
s/v Moondancer's Avatar

Join Date: Nov 2008
Location: Fiji but heading for Alaska
Boat: Tayana 55
Posts: 1,225
One very windy night in a marina in Scotland I thought I was sleeping in a violin and it turned out to be the topping lift/main sheet tension that turned the topping lift into a very tight violin string being plucked by the gale.
__________________
Phil

"Remember, experience only means that you screw-up less often."
s/v Moondancer is offline   Reply With Quote
Old 29-10-2009, 14:58   #15
RTB
Registered User
 
RTB's Avatar

Join Date: Nov 2008
Location: Home port Kemah, TX Currently in Brunswick Georgia
Boat: Hunter 36
Posts: 1,509
Images: 2
These Ladies are always speaking to us....
__________________

__________________
RTB is offline   Reply With Quote
Reply

Tags
mast

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Mast Pumping - Is This Normal? Sergy Deck hardware: Rigging, Sails & Hoisting 10 13-08-2009 21:00
Vibrating Tiller gbendaly Seamanship & Boat Handling 8 19-06-2009 14:17
Plumbing / tank pumping question Cormorant Plumbing Systems and Fixtures 18 30-01-2009 16:34
head isn't pumping water Aquah0lic Plumbing Systems and Fixtures 20 03-01-2009 13:54
Pumping of POO Therapy Plumbing Systems and Fixtures 26 24-10-2007 21:11



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 20:38.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.