luff pockets

[simonfraser]

Hi,
researching mainsail design on the net for a new fully battened flat topped main i came accross luff pockets, what are they ??

windsurfing sails seem to have them, but i can't find any details.

on a slightly different note, i have seen some mains with the luff brought foreward between the attachment points of the battens, i guess to make the airflow behind the mast better i.e. no gap between the aft section of the mast and the luff of the main. any idea what the improvement of this would be???

 

[William_H]

I have no idea what a luff pocket is unless it is to accept the inboard end of the batten.

Batten inboard ends come in a variety of styles. The sophisticated ones have a slider even rollers that go into the mast track. These take up a fair bit of batten lenght so it would be normal to have a cut out(of the sail cloth) to house the fitting. ie the luff extends to the mast.
Less sophistacated for smaller sails has a plastic adjustable expansion box arrangement but at the track just relies on the bolt rope. Or simplest is just a plastic socket (2 halves) screwed to the
cloth again relying on the bolt rope for support at the mast. This just has a piece of string at the leach for adjustment. Others have a pocket at the leach to drop the batten end into.
Mnay with luff sliders have additional sliders at the batten ends.

In my case because of the way I run the spin from the cockpit the halyard always seems to catch on the bits of batten protruduing from the leach. A real pain. My batten holding at the leach is done by a flap of velcro (hook and pile) which goes around the end of the batten and goes into the batten pocket to mate on the inside. You have to unmate the velcro with a steel ruler pushed into the batten pocket for adjustment. Not very satisfacory. So I really don't have an answer to what is best for batten adjustment
Are you having a bolt rope for the luff or going to fit sliders. I have always had a bolt rope and find it most suitable especially for reefing but you need a good feeder. (Bolt rope into mast track)
I don't think a small gap between the luff and the mast will make much difference to airflow. good luck olewill

 

[simonfraser]

thanks will,
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These take up a fair bit of batten lenght so it would be normal to have a cut out(of the sail cloth) to house the fitting. ie the luff extends to the mast.
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that sounds like a good idea, looks good too.

i don't think my code zero sheet will catch the leach of the main, different heights, but it's a good thought.

Simon