Batten tension?

[KenMcCulloch]

Our new boat has a fully battened main, a weird new-fangled device for someone like me who is only just coming to terms with not having peak & throat halyards. The batten cars have a cunning arrangement (a screw) to allow adjustment of the compressive force applied to the battens. How do we arrive at the optimum setting for these adjustments?

 

[AngusMcDoon]

Adjustment of these is only really important if you have a backstay-less rig and a very large roach, as found on multihulls and B&R rigs, as these sails have much higher batten compression loads from the roach when the mainsheet is on hard.

If you have a normal backstayed rig and small roach, hand tightness of the battens is fine. If at the haylard tension to get the point of maximum depth of draft in the correct place (40%) you do not get any vertical crease up the sail just behind the mast, everything is fine at your current batten compression setting.

I have a picture somewhere of insufficient batten compression with a corresponding vertical crease which I can post if anyone wants to see it.

 

[Robin]

There are different systems for adjustment, ours from Crusader always had round battens and screw adjusters both ends. These screws have small plastic inserts in the threads to stop them coming loose, so adjust the mast end one at least until that insert is in the thread. The outer end needs only to be tightened just enough to take out any creases in the batten pockets, at least as an initial setting, but again make sure the plastic thread locking insert is in place. Thereafter adjustment is very much fine tuning, more tension makes for more camber, less makes for flatter and as AngusMcDoon says check no hard vertical creases arise with the halyard tension set. I've only ever adjusted the settings once each season and the secondary fine tuning was usually only of the top or maybe top two battens so as to get the telltales flying properly with all the others.

Beware also too much tension as this will put a lot of pressure on the mast cars and make hoisting and dropping the sail harder and especially so on the lower end systems without fancy roller bearing cars running on a proper mast track.

Enjoy the sail, you will find it a whole lot better.

 

[KenMcCulloch]

Thanks guys, very helpful in that you confirm my intuitions.

 

[johnalison]

My sailmaker's advice is to begin by tensioning just enough to spread out the creases, and go from there according to taste.

 

[semolina pilchard]

Cherry Ripe

Congratulations on getting a really great boat,Ken.
I passed my yachtmaster on her back in 1999.

 

[DavidMcMullan]

I was told to put enough tension on to give a slight bow in the batten, but not too much that causes the batten remain 'bowed to windward' when tacking in light airs.