Split backstay mod

[zoidberg]

Inspecting my Y-shaped split backstay, which has two separate lower legs with two separate rigging screws, with forks to a s/s triangle plate.

What might be the merits or otherwise of changing this, fitting a sheave-block and an inverted-V single cable as the new 'lower legs'..... besides saving one rigging screw....?

 

[rob2]

OK, quite a few things to consider here. One advantage of the original set-up is that should one of the lower legs break, there;s a good chance the rig will survive on the other one rather than topple foward. Simply changing to a single lower on a pulley introduces weak points without benefit, such as the pully pivot. To run over a pulley, the new lower span would have to be of 7x7 construction for flexibility rather than the usual (rigid) 1x19 type.

But why use a turnbuckle when a tackle would offer backstay tension adjustment? This is a common configuration on a fractional rig - with a wire strop spanning the tackle to prevent the rig becoming unsupported should the tackle fail.
On a masthead rig there is less potential for rig tuning with such a configuration, though as the mast is usually much stiffer.

Rob.

 

[Poignard]

I replaced my inverted Y backstays with twin backstays. It seemed a simpler configuration and also enabled me to fit a tackle between the backstays which enables easy tensioning.

 

[William_H]

Much depends on the rig. For a typical fractional rig the backstay is an adjustable control not absolutely vital to holding the mast up. The loads on the back stay are less and a sheave at the bottom of the backstay main wire and a running 7x19 wire attached one side and a tackle the other is common. Makes for quick and easy back stay tensioning. (reccomended)

However a typical mast head rig will rely on the backstay integrity to hold up the mast. Further the force needed to effect significant mast bending are much greater. Indeed many do not bother. The common way to get adjustable tension then is to make up a box of 2 sheaves that the 2 bottom legs of the back stay run through.This box is pulled downwards by a tackle to force the 2 legs closer so tensioning the back stay. Let it run up wards for less tension.
This system has the advantage of keeping the backstay in place even with no tension applied via the sheave box and so is more reliable. If You do not need to adjust backstay tension while sailing. (ie for stronger winds so greater forestay tension) then I would suggest OP leave as is. Not worth the loss of reliability to change to a sheave and one turnscrew.

 

[zoidberg]

Thanks, WilH. That figures, so that's what I'll do.