Mast tuning

[Fire Escape]

I have had my 29.5 hunter only a few years. The club I belong to requires that all masts be un-stepped for winter storage. With the 29.5 being the typical B&R rig with no back stay, all the mast adjustments are done with two side shrouds and the head stay. Stepping the mast in spring and then going through the various adjustments to finally get the mast bent just right sometimes takes several weeks. If I follow the instructions that came with the owners manual the shrouds are way too tight and the mast has too much bend in it. So I have come up with my own system using a wire tension gauge. It's not perfect, but it works. Having a mast that requires a certain amount of bent in it is always a balancing act. Too much or to little bent will mis-shape the main sail.

Is there any 29.5 owner (or other Hunter model that does not have a back stay) out there with with more experience setting up this type of mast system and have developed what they feel is good system that can be set up quickly.

 

[Patrik]

Hi,
We do this every year with our 356 and it works quite well. Make sure you measure the free space within every turnbuckle (?) in the fall so you can put it back next spring and get the same distance, tension and mast bend again.We also use a tension gauge and we try to tension almost up to 20% of breakingpoint (recommended in som article I have read).
Good luck

Patrik

 

[Alan]

Not quite sure I understand how you determined that the "...shrouds are way too tight and the mast has too much bend in it." Double spreader B&R rigs normally have more mast bend in them than other designs. The amount of prebend dialed into the mast is set by the diagonals and is usually done with the mast on the ground. The headstay adjustment is only use to adjust mast rake and the cap shrouds set the amount of headstay sag.
How much prebend are you carrying and what are the settings of your cap shrouds?

 

[Bob 04 H260]

I am a new owner of a single spreader B&R rig, and am trying to learn how to tune it as well. I find if I tighten the shrouds anywhere near the recommended tension I put more bend in the mast and the diagonals become loose.

I have one diagonal that touches a shroud, the Hunter dealer told this was "normal" on many Hunters and not to worry about wear or alignment, is this correct ?

I have access to a Loos gauge and will try to use it when I get the mast back up in a couple of weeks time.

The manual for this boat gives no guidance on setup of the rigging. I have read two detailed posts from 260 owners about the methods they use to setup the rigging, neither makes mention of these two issues.

 

[Alan]

Bob, here's a link to a detailed discussion of tuning the B&R.
http://sbo.sailboatowners.com/index.php?option=com_content&task=view&id=35&Itemid=87
As you note, the diagonals slacken as more prebend is dialed in by the shrouds. The diagonals pull out the prebend as they are tensioned. In this way you can control both cap shroud tension and prebend amount.
Do not worry about the diagonals touching eachother, it is a non factor. If you like you could tape the crossing point together with rigging tape.

 

[Scott B]

Selden Mast Tuning Guide

 

[Bob 04 H260]

good information, thanks Bob