Com-Pac Yacht Owners Association

Com-Pac Model Specific Discussions => CP-23's => Topic started by: johnny b on November 19, 2009, 09:01:36 PM

Title: Asymmetric backstay
Post by: johnny b on November 19, 2009, 09:01:36 PM
I haven't seen this topic discussed anywhere, and have always been curious about it.  Many boats have backstays that split into two several feet above the deck and attach a two stern points on either side of the tiller.  But on many boats, including my CP 23 Mark I, there is only one backstay, and it attaches about a foot to one side (in my case, starboard) of the tiller. 

1) Is this a problem?  Over time, will this slight additional pull to starboard affect the shape of the mast, or the performance on starboard vs. port tack?

2) Why is the rigging designed this way?  There is already a point where a second cable is attached: the pigtail / topping-lift.  It seems like it would be easy to attach another cable there to run to the stern on the port side, for balance.  Or isn't it that important?

Thanks!
Title: Re: Asymmetric backstay
Post by: Steve Ullrich on November 20, 2009, 08:08:22 AM
On two of my previous sailboats the backstay was split and attached to plates on the stern corners.  I would guess that the most likely reason was to keep the backstay clear of the tiller/rudder assembly...

Quote from: johnny b on November 19, 2009, 09:01:36 PM
I haven't seen this topic discussed anywhere, and have always been curious about it.  Many boats have backstays that split into two several feet above the deck and attach a two stern points on either side of the tiller.  But on many boats, including my CP 23 Mark I, there is only one backstay, and it attaches about a foot to one side (in my case, starboard) of the tiller. 

1) Is this a problem?  Over time, will this slight additional pull to starboard affect the shape of the mast, or the performance on starboard vs. port tack?

2) Why is the rigging designed this way?  There is already a point where a second cable is attached: the pigtail / topping-lift.  It seems like it would be easy to attach another cable there to run to the stern on the port side, for balance.  Or isn't it that important?

Thanks!
Title: Re: Asymmetric backstay
Post by: brackish on November 20, 2009, 08:52:38 AM
I think most of the time when a boat maker goes to the expense to split the backstay it is so it can be made adjustable putting some type of roller yoke on the split to tension it differently and define the mast rake/bend.  I don't think there is any inherent problem with the back stay slightly off center, particularly with a six shroud system to maintain lateral centering.

Frank 2
Title: Re: Asymmetric backstay
Post by: Potcake boy on November 20, 2009, 05:53:26 PM
Brackish stated it quite concisely - have you noticed your forestay is off center to the port a little bit.  Kind of like driving one of those bent frame cars that go down the road skewed to one side.
Title: Re: Asymmetric backstay
Post by: Bob23 on November 20, 2009, 07:31:13 PM
The 'Vette was one of Chevys best cars. Not likely to be revived in any form under Obama Motors.
Bob23
Title: Re: Asymmetric backstay
Post by: Craig Weis on November 21, 2009, 11:44:09 AM
Asymmetric backstay is used because it can be rigged to be tightened up or loosened via hydraulics, or manual come-a-long to bend the mast. No other good reason for two backstays or backstays even in the center. Off center is OK mast won't know the difference.
skip.