Irwin 21 Mini-Ton
Description
The Irwin Mini-Ton (also spelled Mini Ton or Mini-Tone) is a fiberglass masthead sloop designed by naval architects Ted Irwin and O. H. Rodgers and built by Irwin Yachts from 1978 to 1980. As part of the International Offshore Rule (IOR) Mini Ton class (boats under 16.5 ft IOR rating), it was engineered for competitive offshore racing, emphasizing high performance, light weight, and agility over cruising comfort. With a narrow, low-displacement hull, deep fin keel, and spade rudder, it's optimized for upwind speed and handling in moderate winds, suitable for one-design races or handicap events like the Southern Ocean Racing Conference (SORC) qualifiers. The design is closely related to (or identical to) the Irwin Free Spirit, another Mini Ton racer from the same era. Approximately 10-20 hulls were produced, making it extremely rare and a collector's item for vintage racing enthusiasts today. 1800 lbs. Disp. 750 lbs. Ballast 18'6" Ballast 8' Beam
Construction Details
| Designer | Ted Irwin |
|---|---|
| Length | 20.840 ft |
| LOA | 20.810 ft |
| LWL | 16.500 ft |
| Beam | 8.000 ft |
| Displacement | 1900 lb |
| Max Draft | 4.500 ft |
| Min Draft | 0.800 ft |
The standard boat dimensions
| i | 24.50 ft |
|---|---|
| j | 8 ft |
| p | 24.50 ft |
| e | 8.50 ft |
| p2 | - |
| e2 | - |
| i2 | - |
| j2 | - |
| I | J | P | E | P2 | E2 | I2 | J2 |
|---|---|---|---|---|---|---|---|
| 24.50 ft | 8 ft | 24.50 ft | 8.50 ft | - | - | - | - |
Blueprints
Sails
| Sail Type | MAINSAIL |
|---|---|
| Luff | * 24.5 ft - (7468 mm) |
| Foot | * 8.5 ft - (2591 mm) |
| Leech | * 25.47 ft - (7763 mm) |
| Tack Angle | * 88 ° |
| Diagonal | * 25.65 ft - (7818 mm) |
| Head (inches) | * 4 in - (102 mm) |
| Area | * 107.65 ft² |
| Sail Type | JIBSAIL |
|---|---|
| Luff | * 20.62 ft - (6285 mm) |
| Foot | * 10.63 ft - (3240 mm) |
| Leech | * 17.85 ft - (5441 mm) |
| Percentage LP | * 115 % |
| Length Perpendicular | * 9.2 ft - (2804 mm) |
| Deck Angle | * 11.97 ° |
| Area | * 94.86 ft² |
| Sail Type | JIBSAIL |
|---|---|
| Luff | 24.25 ft - (7391 mm) |
| Foot | 8.5 ft - (2591 mm) |
| Leech | 22.167 ft - (6757 mm) |
| Percentage LP | * 96.88 % |
| Length Perpendicular | * 7.75 ft - (2362 mm) |
| Deck Angle | * 6.11 ° |
| Area | * 94.01 ft² |
| Sail Type | GENOA |
|---|---|
| Luff | 24.5 ft - (7468 mm) |
| Foot | 12.92 ft - (3938 mm) |
| Leech | 23.083 ft - (7036 mm) |
| Percentage LP | * 150 % |
| Length Perpendicular | * 12 ft - (3658 mm) |
| Deck Angle | * 3.64 ° |
| Area | * 147.03 ft² |
| Sail Type | GENOA |
|---|---|
| Luff | 24.25 ft - (7391 mm) |
| Foot | 11.25 ft - (3429 mm) |
| Leech | 22.5 ft - (6858 mm) |
| Percentage LP | * 130 % |
| Length Perpendicular | * 10.4 ft - (3170 mm) |
| Deck Angle | * 4.37 ° |
| Area | * 126.07 ft² |
| Sail Type | DRIFTER |
|---|---|
| Luff | * 24.48 ft - (7462 mm) |
| Foot | * 13.48 ft - (4109 mm) |
| Leech | * 21.92 ft - (6681 mm) |
| Perc LP | * 150 % |
| Length Perp | * 12 ft - (3658 mm) |
| Deck Angle | * 9 ° |
| Area | * 146.9 ft² |
| Sail Type | ASYMMETRICAL |
|---|---|
| Luff | * 24.48 ft - (7462 mm) |
| Foot | * 13.2 ft - (4023 mm) |
| Leech | * 22.52 ft - (6864 mm) |
| Perc LP | * 165 % |
| Area | * 242 ft² |
| Sail Type | SPINNAKER |
|---|---|
| Stays | * 24.48 ft - (7462 mm) |
| MidGirth | * 14.4 ft - (4389 mm) |
| Foot | * 14.4 ft - (4389 mm) |
| Perc LP | * 180 % |
| Area | * 300 ft² |
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.