Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 14-04-2012, 23:31   #1
Registered User

Join Date: Jun 2011
Location: Sydney, Australia
Boat: 36ft Timber Ketch
Posts: 75
Box construction masts, rigging tension.

I'm attempting to retune the rigging on my wooden boat with box construction masts. Being a wooden boat I know the tension is not suppose to be that of a glass or steel boat however the mast has a shake in it by which I mean it can be shaken from the deck with little effort. Surely the rigging is too loose however I'm wondering which order to tension the stays in. I've messed around with it over and over and can't seem to get it right so I'll start by loosening all stays and (in a calm bay) retune from scratch. Any advice would be appreciated remembering it's an older timber yacht (ketch).
Attached Thumbnails
Click image for larger version

Name:	image-2601379162.png
Views:	100
Size:	122.3 KB
ID:	39954  
__________________

__________________
Nikos Baillie is offline   Reply With Quote
Old 14-04-2012, 23:59   #2
Registered User
 
TeddyDiver's Avatar

Join Date: Aug 2010
Location: Arctic Ocean
Boat: Under construction 35' ketch
Posts: 1,826
Images: 2
Re: Box construction masts, rigging tension.

Is it deck or keel stepped? Either way wouldn't tension more than so much the lee stays will still get a bit of slack i moderate wind.
BR Teddy

PS beautiful boat
__________________

__________________
TeddyDiver is offline   Reply With Quote
Old 15-04-2012, 00:40   #3
Registered User

Join Date: Jun 2011
Location: Sydney, Australia
Boat: 36ft Timber Ketch
Posts: 75
Keel stepped. I think I need to loosen all stays and then start by tensioning the upper shrouds first and then the lower shrouds. Thanks, she just turned fifty and I'm hoping to ensure she has fifty more.
__________________
Nikos Baillie is offline   Reply With Quote
Old 15-04-2012, 09:33   #4
Registered User
 
S/V Alchemy's Avatar

Join Date: May 2008
Location: Toronto
Boat: Custom 41' Steel Pilothouse Cutter
Posts: 4,575
Re: Box construction masts, rigging tension.

Hmm...I never really considered that wooden boat rigs had to be comparatively slack, but I can see why.

I wonder if the solution isn't to assemble a metal frame thru-bolted to the wooden frames for a greater distance than the normal strap-type chain plates. The stays could be secured to these frames, which would spread the compression loads "around" the hull via the entirety of the frames. The mast steps would need to be beefed up in a similar fashion.

I believe I've seen examples of this logic in some late wooden boats; I know our commodore's 1921 R-boat has had all its frames redone with extensive glassing in order to make the whole structure more "monocoque", if that makes sense.
__________________
Can't sleep? Read www.alchemy2009.blogspot.com for fast relief. Can't read? Avoid www.volumesofsalt.blogspot.com, because it's just personal reviews of sea books.
S/V Alchemy is offline   Reply With Quote
Old 15-04-2012, 09:58   #5
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,352
Re: Box construction masts, rigging tension.

Does the rig pump when sailing? or you just noticed that you can make it pump by hand? You might take 'er sailing with a helper to steer and adjust going to weather.
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 15-04-2012, 10:06   #6
Registered User
 
Ziggy's Avatar

Join Date: Apr 2008
Location: U.S., Northeast
Boat: Contessa 32
Posts: 1,421
Images: 2
Re: Box construction masts, rigging tension.

You really should post your question on The WoodenBoat Forum. I'm not sure there are enough people qualified to answer it here.
__________________
... He knows the chart is not the sea.
-- Philip Booth, Chart 1203
Ziggy is online now   Reply With Quote
Old 15-04-2012, 10:14   #7
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
Re: Box construction masts, rigging tension.

I would agree that pre-tensioning followed by fine tuning on a flat water upwind work solves many questions. I like the wind to be 10-15 knots for that but I bet this is boat specific.

IMHO if the boat hull is stiff then once pre-tensioned, the rigging needs very little tuning.

b.
__________________
barnakiel is offline   Reply With Quote
Old 15-04-2012, 10:22   #8
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,352
Re: Box construction masts, rigging tension.

Quote:
Originally Posted by barnakiel View Post
I would agree that pre-tensioning followed by fine tuning on a flat water upwind work solves many questions. I like the wind to be 10-15 knots for that but I bet this is boat specific.

IMHO if the boat hull is stiff then once pre-tensioned, the rigging needs very little tuning.

b.
Yeah...10-15 is a good range. After 20 you may not get the forward bend at the top out on some boats....
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 15-04-2012, 12:49   #9
Senior Cruiser
 
SkiprJohn's Avatar

Cruisers Forum Supporter

Join Date: May 2006
Location: Kea'au, Big Island, Hawaii
Boat: Cascade, Sloop, 42 - "Casual"
Posts: 14,192
Re: Box construction masts, rigging tension.

This is definitely not a calibrated tune but will get you started. You may find other more technically written tuning directions and please follow them if they were for wood masts and wood boats.
With my old wooden ketch it was tuning at the dock just getting the slack out of the uppers first then the fore and aft shrouds. To get your mast straight and perpendicular to the deck use your jib halyard and first measure to either port or starboard chainplate then swing it over to the opposite side. Tension the uppers to deflect a couple inches while tugging at them with about 35 lbs of pressure. Once you've set up your uppers then lay on the deck and sight up the mast and take out any bend with your lowers. Now its time to go to sea in 10-15 to make certain your leeward shrouds are not too slack and slap around a lot. Sight up the mast and make note of any bend when sailing to windward on both tacks. Tighten to take out bends and tighten equally to take out slack. Its always much easier to do your adjustments on the leeward shrouds so do some tacking back and forth to get it set up.
It's never good to overtighten standing rigging on a wood boat so be cautious not to do that.
You have a beautiful boat.
kind regards,
__________________
John
SkiprJohn is offline   Reply With Quote
Old 16-04-2012, 00:02   #10
Registered User

Join Date: Jun 2011
Location: Sydney, Australia
Boat: 36ft Timber Ketch
Posts: 75
Well thanks to everyone for so many responses. Never need to hire an over priced professional again with all this great advice. Alchemy, the chain plates are in good order but were my first suspect yet could of course always use some more beefing up like you had done to yours. Cheechako, I've been sailing with her while the masts have been like this but like you mentioned I would need someone there to steer to get a really good idea of how much movement they have underway, I am sure however that they would never shake by hand before like they do now. Also the main line is attached to the mizzen mast so upon an sort of gybe the shake on both masts is evident. Skipper John, the idea of measuring the center with a jib halyard is genius! The rest of the advice will be put to use today and tomorrow and I will let you all know how it goes. I'm thinking I'm to tension all the upper shrouds first and for most before fiddling around with the lowers. Also I think I've been putting too many turns per adjustment, one and a half to two, where as I should be doing half turns per shroud. I really thought this would be something I would have solved by messing around for a few hours until perfect however it's turned out to be more challenging. The way I see it is that once I've done it I'll know how forever. Don't know how many people on this forum are from Sydney but the prices here for slipways and specialists is ridiculous so all this help is appreciated. Nikos from Gwenn a Du.
__________________

__________________
Nikos Baillie is offline   Reply With Quote
Reply

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




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 19:24.


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.