The cruising sailors friend - a self tacking jib. This design can be adapted to most boats with little problem and a few simple modifications.
This system is used on a Merit 25, I=28.75 ft (8.76 m) and J=9.66 ft (2.94 m). The boat is 24.5 ft (7.47 m) long and weighs 3,120 lb (1,415 kg) in measurement trim.
Quoting from Fishmeal:
"The decision to develop a "floating track" for a self-tacking jib was driven by two considerations:
1) The boat is heavily raced and often sails with 150% or larger overlapping deck-sweeping jibs. A conventional track would be a serious obstruction during tacks. But unlike a fixed track, the ends of the floating track lie flat on the deck when not in use (and the track is easily unrigged and removed to clean things up even more on light-air days).
2) The elimination of the sheet block on the car allows the radius of the track to be larger without violating the "low energy at the ends" condition necessary for easy self-tacking. Rule of thumb for conventional (Soling style) self-tacking tracks is to have track radius approximately equal to the J measurement. For the floating track, radius equal to half the jib hoist appears more then adequate, and a larger radius (nearly straight) track would probably work".
This picture gives a good idea of the simplicity of adapting the "Rocky Rail" to almost any boat -- DO NOT just copy this make sure to get the whole story and see the MkIIver2 info -- you really need to read the whole story - it can be found at the Fishmeal Site site.