The original and I.O.R. sail plans for the Alpa 11.50. Note difference in the mainsails on the two different plans. The foot of the IOR mainsail being much shorter.
The cut of the jib is also interesting: the foot is cut in such a way that the clew corresponds to the goose neck of the boom. This is typical of S&S designs of that area like the Swan 36 or the Sagitta 35. On the later S&S Swans (37 and 38) the jib clews are slightly lower than the boom…
Original Sail Plan
I.O.R. Sail Plan
IOR Sail Dimensions
| Sail | Foot | Luff | Leech | Area | Cloth Weight |
|---|---|---|---|---|---|
| Genoa 1 (Light) | 7.840 | 13.500 | 13.000 | 53.5 | 142 |
| Genoa 2 (Intermediate) | 7.100 | 12.700 | 12.240 | 42.3 | 325 |
| Genoa 3 (Heavy) | 6.380 | 12.040 | 11.200 | 35.4 | 325 |
| Jib | 5.000 | 9.600 | 8.100 | 20.4 | 227 |
| Storm Jib | 3.640 | 7.120 | 5.420 | 9.5 | 340 |
| Wide Spin Staysail | 7.840 | 7.120 | 8.700 | 26.2 | 75 |
| Spinnaker | 8.960 | 14.090 | 14.090 | Max IOR | 45 |
| Drifter | 7.840 | 13.500 | 13.000 | 53.5 | 65 |
| Mainsail | 3.270 | 11.500 | 11.960 | 21 | 206 |
| Max Sail Area | 74.5 |
IOR Rating Measurements
Foretriangle I = 13.200 J = 4.940 Area = 32.6 m2
Mainsail P = 11.500 E = 3.270 Area 18.8 m2
Total Sail Area 51.40 m2