Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 23-02-2017, 08:24   #1
Registered User

Join Date: Feb 2015
Posts: 13
Adding Running Backstays

Hello,

I own a Cabot 36 full keel double headsail sloop. Built in 1977. Single spreader with fore and aft lower shrouds. The original configuration included a boomed self tacking staysail in addition to a jib. The staysail and hardware had been lost by the previous owner when I bought the boat so I never saw it. I would like to add a loose footed staysail. There never were running backstays for the boomed staysail and I wonder if I need them now with a loose footed staysail. Does a club footed staysail not require running backstays or was this an oversight on the part of the architect (Ted Brewer so I doubt it) ?

The inner stay tang is welded to the mast. The chainplate/tang at deck level is attached to a bulkhead. Is it appropriate to weld the backstay tangs to the mast or is through bolting a better option ?

Thanks for your help

Mike Wybo
mwybo is offline   Reply With Quote
Old 23-02-2017, 08:37   #2
Registered User
 
UNCIVILIZED's Avatar

Join Date: Jun 2014
Location: Up the mast, looking for clean wind.
Boat: Currently Shopping, & Heavily in LUST!
Posts: 5,629
Re: Adding Running Backstays

Bolting is the norm. Welding weakens aluminum due to the heat involved. And also it's easier to configure bolt hung tangs to accomodate stay articulation & flexing.
__________________

The Uncommon Thing, The Hard Thing, The Important Thing (in Life): Making Promises to Yourself, And Keeping Them.
UNCIVILIZED is offline   Reply With Quote
Old 23-02-2017, 08:40   #3
Registered User
 
Suijin's Avatar

Join Date: Feb 2013
Location: Bumping around the Caribbean
Boat: Valiant 40
Posts: 4,625
Re: Adding Running Backstays

Quote:
Originally Posted by mwybo View Post
Hello,

I own a Cabot 36 full keel double headsail sloop. Built in 1977. Single spreader with fore and aft lower shrouds. The original configuration included a boomed self tacking staysail in addition to a jib. The staysail and hardware had been lost by the previous owner when I bought the boat so I never saw it. I would like to add a loose footed staysail. There never were running backstays for the boomed staysail and I wonder if I need them now with a loose footed staysail. Does a club footed staysail not require running backstays or was this an oversight on the part of the architect (Ted Brewer so I doubt it) ?

The inner stay tang is welded to the mast. The chainplate/tang at deck level is attached to a bulkhead. Is it appropriate to weld the backstay tangs to the mast or is through bolting a better option ?

Thanks for your help

Mike Wybo
The simplest solution is the best. Send Ted an email and ask him about it. I'm sure that he'd be more than happy to discuss it.

His email:

brewer@island.net
Suijin is offline   Reply With Quote
Old 23-02-2017, 08:46   #4
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29° 49.16’ N 82° 25.82’ W
Boat: Pearson 422
Posts: 16,306
Re: Adding Running Backstays

Not sure why no runners but I see no negatives in adding them and a few positives.

Would not weld the tangs on. My admittedly amateur understanding of metalurgy is welds are not the strongest part of a connection and better to take force on a bolted connection. Also welding aluminum is tricky and could result in a weak spot on the mast.
__________________
The water is always bluer on the other side of the ocean.
Sometimes it's necessary to state the obvious for the benefit of the oblivious.
Rust is the poor man's Loctite.
skipmac is offline   Reply With Quote
Old 23-02-2017, 08:50   #5
Moderator
 
neilpride's Avatar

Join Date: Jul 2009
Location: Sxm , Spain
Boat: CSY 44 Tall rig Sold!
Posts: 4,367
Re: Adding Running Backstays

How far is the inner tang from the masthead ?
neilpride is offline   Reply With Quote
Old 23-02-2017, 09:09   #6
Registered User

Join Date: Feb 2015
Posts: 13
Re: Adding Running Backstays

Suijin: I have emailed M. Brewer and will share his response. Thanks for the address

neilpride: Great question, I have that info elsewhere and will post it later.


Mike Wybo
mwybo is offline   Reply With Quote
Old 23-02-2017, 09:31   #7
Registered User
 
markwesti's Avatar

Join Date: Feb 2010
Location: Long Beach Ca.
Boat: Westsail 28
Posts: 353
Re: Adding Running Backstays

Hi Mike , from the sailboat data pic I don't see any staysail back stays . And the staysail head stay is way up there . Of course Mr. Brewer will be the final word and I will be interested to hear . I see now why you referred to your boat as a double head sail sloop , by comparison a Westsails' staysail back stays attach at the spreader .
CABOT 36 sailboat specifications and details on sailboatdata.com
markwesti is offline   Reply With Quote
Old 23-02-2017, 10:14   #8
Registered User

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 20,420
Re: Adding Running Backstays

If the new stay attaches in between the rigging that stays the mast aft, you need runners in any serious conditions (wind/waves).

Otherwise the sail can pull the mast far enough out of column to break it.

b.
barnakiel is offline   Reply With Quote
Old 23-02-2017, 10:45   #9
Registered User

Join Date: Feb 2015
Posts: 13
Re: Adding Running Backstays

Here is part of the reply I had from Ted brewer, the architect for the Cabot 36

"I suppose the builders decided that the stays'l stay did not require runners, but we did show them on the drawings."

I guess that settles it !

One last question for this thread. I've read that both a 4:1 purchase tightened by hand is best and that a 1:1 on a winch is best for securing the working running backstay. Any experience with either (or preferably both) ?

Thanks .

Mike Wybo
mwybo is offline   Reply With Quote
Old 23-02-2017, 11:10   #10
Registered User
 
UNCIVILIZED's Avatar

Join Date: Jun 2014
Location: Up the mast, looking for clean wind.
Boat: Currently Shopping, & Heavily in LUST!
Posts: 5,629
Re: Adding Running Backstays

4:1 is quite common, but were it me, I'd design things so that the tail end coming out of the tackle could easily be led to a winch. One reason being that when you account for friction in a 4:1, you get about 3:1 efficency. So then if you can pull on the line with 50lbs of force by hand, that's 150lb of tension on the stay. Which is no where near the nominal 20-25% breaking strength that standing rigging is routinely tuned to. Not that they necessarily need to be quite so tight, but having the ability to crank them up a bit more than by hand is better than not.

Also, if you can't lead them to a winch, then you'll be relying on the built in cam cleat on a block to fully hold 25% of the load on the stay. And even if said cleat can mechanically hold this much, it may not be enough if the load on the stay gets real high. Plus which, at higher loads, cam cleats tend to chew up lines via their sharp teeth.

Just my $0.02 anyway
__________________

The Uncommon Thing, The Hard Thing, The Important Thing (in Life): Making Promises to Yourself, And Keeping Them.
UNCIVILIZED is offline   Reply With Quote
Old 23-02-2017, 11:13   #11
Marine Service Provider

Join Date: May 2012
Location: New Orleans
Boat: We have a problem... A serious addiction issue.
Posts: 3,974
Re: Adding Running Backstays

Quote:
Originally Posted by mwybo View Post
Here is part of the reply I had from Ted brewer, the architect for the Cabot 36

"I suppose the builders decided that the stays'l stay did not require runners, but we did show them on the drawings."

I guess that settles it !

One last question for this thread. I've read that both a 4:1 purchase tightened by hand is best and that a 1:1 on a winch is best for securing the working running backstay. Any experience with either (or preferably both) ?

Thanks .

Mike Wybo
For simplicity you can route the runners to the jib winches since the windward winch should generally be free when you use the runners so you justhave to buy one block a side. But if you can get enough purchase with a block and tackle and attached cam cleat that works too.

The amount of purchase you need is pretty boat dependent, some rigs like a lot of runner, others just want it snuggled up a touch. I would ask the designer how much load they predicted on the runners (if he knows off hand) or what system was drawn for the runners from the get go.
__________________
Greg

- If animals weren't meant to be eaten then they wouldn't be made of food.
Stumble is offline   Reply With Quote
Old 23-02-2017, 11:18   #12
Moderator Emeritus
 
roverhi's Avatar

Join Date: Aug 2005
Location: Carlsbad, CA
Boat: 1976 Sabre 28-2
Posts: 7,505
Send a message via Yahoo to roverhi
Re: Adding Running Backstays

The tension on a one to one runner would be excessive and tie up a winch. Wouldn't want to rely on a clutch to hold that line especially if it's dacron over exotic because of core creep.

We had Schaefer Series 7 fiddle blocks led to a cleat for the runners on our Westsail 32. Used them mostly from a close reach to hard on the wind where they could be set up on the lee side before a tack and left alone. The runners don't need to be set up rock hard like a backstay with typical cruising boat telephone pole mast so the 4-1 purchase worked to keep the mast in column.

Runners were not part of the rigging setup for a base boat from Westsail. The mast did have the tangs on the mast but the wire and blocks weren't provided. One of the early boats did a circumnavigation of the Pacific and made it amost alll the way around without running backstays He got caught in a storm off the Oregon coast on the way to closing the circle in SoCal. While working at the mast during the storm he looked up and saw the mast was being pulled seriously out of column. Scared him so much he made an unscheduled stop in SF and installed running backs before he continued the final leg of the sail to Newport Beach.
__________________
Peter O.
'Ae'a, Pearson 35
'Ms American Pie', Sabre 28 Mark II
roverhi is offline   Reply With Quote
Old 23-02-2017, 11:46   #13
Registered User
 
UNCIVILIZED's Avatar

Join Date: Jun 2014
Location: Up the mast, looking for clean wind.
Boat: Currently Shopping, & Heavily in LUST!
Posts: 5,629
Re: Adding Running Backstays

This is one of those "it depends" questions.
Quote:
Originally Posted by roverhi View Post
The tension on a one to one runner would be excessive and tie up a winch. Wouldn't want to rely on a clutch to hold that line especially if it's dacron over exotic because of core creep.
This is really dependent on the boat, the clutch, the line used. Some runners are 1:1, or led to a hyfield lever. There are clutches that'll hold many tons. And high tech lines that are all but creep free.

We had Schaefer Series 7 fiddle blocks led to a cleat for the runners on our Westsail 32. Used them mostly from a close reach to hard on the wind where they could be set up on the lee side before a tack and left alone. The runners don't need to be set up rock hard like a backstay with typical cruising boat telephone pole mast so the 4-1 purchase worked to keep the mast in column.
Some of whether or not the runners need adjusting is based on how stiff the spar is, how much pre-bend is in it, the wind range that the runners get used in, where they're attached to the mast, & a few other things. But some do require adjusting based on wind strength, sail shape, sail trim, etc. Even on non-racing boats. Particularly those with fractional rigs.
__________________

The Uncommon Thing, The Hard Thing, The Important Thing (in Life): Making Promises to Yourself, And Keeping Them.
UNCIVILIZED is offline   Reply With Quote
Old 23-02-2017, 12:12   #14
Registered User
 
markwesti's Avatar

Join Date: Feb 2010
Location: Long Beach Ca.
Boat: Westsail 28
Posts: 353
Re: Adding Running Backstays

Interesting thread . Here is how we do it , please note that I said "how we do it" and not how it should be done haha but please feel free to comment on my set up . First shot , the upper block is a double the wire goes to a tang at the spreader .

Second shot... the single block attaches to a tang on the gunnel , also there is a aft tang should you need more angle there is a horn cleat on the block so you can do the tighten up .
markwesti is offline   Reply With Quote
Old 23-02-2017, 12:41   #15
Marine Service Provider

Join Date: May 2012
Location: New Orleans
Boat: We have a problem... A serious addiction issue.
Posts: 3,974
Re: Adding Running Backstays

Mark,

1) Leeward runners should never be tensioned they actually reduce the design strength of the mast by pulling to the side. Only the windward runner should be tensioned ever.

2) runners should be brought as far back as possible. Ideally to the transom corner or close thereabouts. The further forward they are the less support they provide for a given tension.

3) wire runners are pretty much a thing of the past. Dyneema in some flavor is far preferable due to the reduced weight aloft.

The cascade you are using is a pretty reasonable set up btw. But the amount of purchase you need is very, very rig dependent. On a Trip 40 there practically isn't a backstay an the runners carry the entire rig load. Wi a 2:1 cascade ending in a winch we carried an easy 3,000lbs of tension in anything over 10kn. A J-130 I raced on carried about 50lbs of runner up to 35 knots, and didn't need any until the wind hit 20.

Trimming with a runner isn't that complicated. For a boat with a loaded backstay (almost all cruising boats, and most race boats) the runner just needs enough tension to keep the mast from pumping. Less is almost always better than more. On highly loaded runners you are actually bending the mast and then the runner takes the place of the backstay in determining rig bend so you trim it like a hydrolic backstay.
__________________
Greg

- If animals weren't meant to be eaten then they wouldn't be made of food.
Stumble is offline   Reply With Quote
Reply

Tags
backstays, running backstays

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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
Running Backstays? farotherside Multihull Sailboats 24 13-08-2009 21:59
Running Backstays vs Fixed mestrezat Deck hardware: Rigging, Sails & Hoisting 6 12-08-2009 09:02
Replacement Running Backstays Oceanroaming Deck hardware: Rigging, Sails & Hoisting 30 06-08-2009 06:53
Should we have running backstays ? ribbony Deck hardware: Rigging, Sails & Hoisting 21 19-12-2006 19:39

Advertise Here


All times are GMT -7. The time now is 21:36.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.