: Hi Mike
: 10% of the luff to leach would give me 5 inches of depth. That will give me
: something to shoot for to start with. I am making a 1/8th scale model sail
: out of Tyvex house wrap (those big shipping envelopes you can?t tear) you
: can get in the US post office?s,,,,, and with battens to see what the
: characteristics are. I can check to scale the chamber belly.

: The reason I think the bottom of the sail may not have an angular batten is
: some of the Balogh sails have a zipper reefing and it would seem the
: bottom batten would have to be taken out each time you reefed. I?m not
: sure of that but it looks like if the batten was left in that it would
: bind as you dropped the sail. But I can?t think that through very well.
: Maybe the model will give me the answer. Thanks.

: John

Hi John,
I had a look at Balogh's site and the reefing zip looks to be at the third and second from the top of the sail. That makes perfect sense as those battens are parallel.
In the picture you posted, the blue and yellow sail, the two mid-sail batten pockets look wider than the top batten pocket and the lowermost one, that's where the zip is fitted.

An interesting book on sails is "Sails" by Jeremy Howard-Williams. It's published by Adlard Coles. There's also "Small Boat Sails" by the same author and publisher, basically a condensed version of "Sails" aimed specifically at small boats, dinghy's, etc.
Either should be available at library's, usually the sports section.

Sail design can be fun, and exasperating.
Mike Savage
South West Cork