Hi, Jim.
The short answer:
Because batten pockets distribute strain better than grommets.
The long answer:
I guess it depends on several factors:
- · Batten material
- · DIY or by sailmaker
- · Distance and area of sailing.
Wooden battens, which break instead of bending, favours either tied on battens or a layout with several shorter lengths of batten pockets. This lets one push out broken stubs, or putting on splints, tied on where the pocket gaps are.
Personally I would never want to own wooden battens - they clearly break too often and weigh too much. With bamboo and CFRE unavailable here, I prefer ‘Norway bamboo’ - thin-walled aluminium tubes. These work well with batten pockets.
A sailmaker may possibly make a quicker job of it by banging in grommets on strengthened patches than by sewing on pockets, I dunno, but I, as an amateur have lost confidence in grommets, so all my junksails have been totally free of metal. When using my Amateur Method B of assembling batten panels and adding batten pockets, I bet one would have a hard time making a quicker job with grommets instead.
For short distance sailing, I certainly would only use simple batten pockets. For long distance sails, I guess I would recommend making 5-10 stubs of batten pockets. This, as said, lets one add splints to a damaged batten, and also reef away a damaged panel quite easily. This last problem will not be serious as long as the sail has been given a strong boltrope around it.
The hinge type which Roger Taylor and Jami Jokinen make use of, appears to be very good and reliable, but the method is probably slower to make than any other method (More measuring, checking and double-checking...).
Arne
PS:
I have removed my sails from my boats a few times. Apart from the tiny sail of ‘Broremann’, I untie the sail bundle from the boom before lifting it ashore with the battens still in place. This makes re-rigging the sail easier, as I can rig the boom first, with mastlift and topping lifts plus TP and TL before bringing the sail bundle back on board.
PPS:
Have you launched Hobbit yet?