Andromache 31 1/2 TON
Description
The Andromache 31 1/2 Ton (also listed as Andromache 31 1/2 TON or similar) is an obscure vintage racing sailboat from the late 1970s to early 1980s era, optimized for Half Ton Cup (International Half Ton) class racing or similar IOR (International Offshore Rule) events. The "1/2 Ton" designation refers to the IOR rating band (around 22–25 feet IOR rating, corresponding to boats ~30 ft LOA), not displacement. These were competitive one-design or semi-custom racers emphasizing light-air speed, as noted in historical sail data sources. The designer is listed as Unknown in major databases (likely a custom or limited-production design by a lesser-known naval architect or yard for the Half Ton class). No widespread production builder is tied to it—possibly built by a small European or US yard in low numbers, similar to other IOR-era half-tonners (e.g., evolutions of designs by Ron Holland, Ed Dubois, or local builders).
The standard boat dimensions
| i | 38.95 ft |
|---|---|
| j | 12.10 ft |
| p | 35.95 ft |
| e | 8.14 ft |
| p2 | - |
| e2 | - |
| i2 | - |
| j2 | - |
| I | J | P | E | P2 | E2 | I2 | J2 |
|---|---|---|---|---|---|---|---|
| 38.95 ft | 12.10 ft | 35.95 ft | 8.14 ft | - | - | - | - |
Sails
Andromache 31 1/2 TON - MAINSAIL
| Luff | * 35.95 ft - (10958 mm) |
|---|---|
| Foot | * 8.14 ft - (2481 mm) |
| Leech | * 36.47 ft - (11116 mm) |
| Tack Angle | * 87.99 ° |
| Diagonal | * 36.58 ft - (11150 mm) |
| Head (inches) | * 3.5 in - (89 mm) |
| Area | * 151.16 ft² |
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Andromache 31 1/2 TON - JIBSAIL
| Luff | 32.63 ft - (9946 mm) |
|---|---|
| Foot | * 15.96 ft - (4865 mm) |
| Leech | * 28.46 ft - (8675 mm) |
| Percentage LP | * 115.04 % |
| Length Perpendicular | * 13.92 ft - (4243 mm) |
| Deck Angle | * 12.03 ° |
| Area | * 227.11 ft² |
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Andromache 31 1/2 TON - GENOA
| Luff | 38.75 ft - (11811 mm) |
|---|---|
| Foot | * 19.48 ft - (5938 mm) |
| Leech | * 36.51 ft - (11128 mm) |
| Percentage LP | * 150 % |
| Length Perpendicular | * 18.15 ft - (5532 mm) |
| Deck Angle | * 4.03 ° |
| Area | * 351.68 ft² |
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Andromache 31 1/2 TON - SPINNAKER
| Stays | * 38.75 ft - (11811 mm) |
|---|---|
| MidGirth | * 21.78 ft - (6639 mm) |
| Foot | * 21.78 ft - (6639 mm) |
| Perc LP | * 180 % |
| Area | * 717 ft² |
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Disclaimer. Boats are not all the same -- even when produced in the same factory of the same model. Sailrite does its best to publish accurate dimensions, but we often find it worthwhile to have our customers measure their boats carefully before we produce kits for them. You should take the same precautions, especially when the data is not from Sailrite. The information on this site is not guaranteed to be accurate. Sailrite offers this content as a service to our community, but takes no responsibility for the reliability of the data provided.