Adjustable Backstay?

[lrak]

Hi

I have a split ("y") backstay that I would like to add a simple tensioner / fidle block too. It is for a tophat 25 and some do and some don't already have this in place.

I just want to learn if I need to consider addition stress this will add to the rig and if I need to be careful or if this is no more than standard stress anyhow...

Can I just add a tensioner or do I need to modify the rig to suit?

Any thoughts appreciated.

Cheers


Karl

[mikehoyt]

Try Mike Quill's rigging shop web site. you can find thru Google search. there is a forum on that site and it is a great place to ask this question.

Mike (not Quill)

[sailingdog]

Is your boat a fractional rig or masthead rig? If it is a fractional rig, an adjustable backstay would make sail shape control a lot better, and provided you don't use gorilla tactics to adjust it, probably not strain the rig much. You should probably consult with a rigger to review your rig and check to see it will handle a backstay adjuster. You could do the back stay adjuster in one of two ways. The first is to put a block at the bottom of the center section fo the backstay and then run a wire from one chainplate, through the pulley to a block and tackle that is attached to the other chainplate. With a four-to-one block and tackle, this would give you an 8:1 mechanical advantage in adjusting the backstay. The other is to use a backstay tensioner that rides on the two sections of the split backstay and has a block and tackle to adjust its height and the backstay tension.

Here are images of the two types:
Type 1:


Type 2:

[lrak]

Thanks guys - it is a masthead rig... I will read those links... thanks

[sailingdog]

An adjustable backstay for a masthead rig isn't as useful. It just isn't, because of the fact that a masthead rig mast won't bend the way a fractional rig does.

[knuterikt]

An adjsutable backstay mastheaded rig can give the same possibilities to adjust the bend of the mast as on a masthead rig.

But to make this possible you will need a masthead fitting on the mast where the attachement of the backstay are placed some inches (6?) further aft than the aft wall of the mast section. These masthead fittings are also angled so the aft part sits higher than the forward part.

Mastheaded rigs must always have a basic trim with a litle bit of prebend to avoid the mast beeing bent the wrong way.

So when the rig is set correctly and the rigth astehad fitting is in place adjustable backstay gives the same possibility to adjust the curve of the mast.

On my Benetau First 38 fitted with a hydraulic backstay tensioner it no problem bending the mast the correct way.