Our main has a foot shelf in the bottom. This is an extra flap that provides a bit more area when you slack the outhaul on a run. For the '98 season I did not put the foot of the sail into the slot on the boom. I wanted to see how the sail flew loose footed. I found that overall control over sail shape (especially in the lower third of the sail) was greatly improved. Some people say that flying the main loose footed like this eliminates (or reduces) the endplate effect of the boom. The end plate effect blocks air flow under the foot of the main which decreases it's efficiency. Deck sweeping genoas are an effort to exploit the endplate effect using the deck as the endplate. C.A. Marchaj studied this effect on the main sail in his classic text "Sailing Theory and Practice" and concluded that there is indeed an effect to be taken advantage of but you need an endplate about the size of a surf board on a sail this size. This is impractical on a boom like the P26's. I think the enhanced control over mainsail shape is more advantageous. If I were having a new main built I would get it loose footed with a big foot roach. Consult your sailmaker.
The photo also shows the small windsurfer Windex I mounted to the backstay. This is a nice indicator of shear from the top of the mast to the bottom when you compare it to the masthead windex.
Another photo of the main sail...
Reefing...
| Luff | 27.50 ft |
| Leech | 28.96 ft |
| Foot | 10.00 ft |
| Area | 138 sf |
Other photos that show the main sail...
 Another photo |
 Main and WJ |
 Main and 130 |
 Main and 150 |
 Reefing |
