Irwin 37 Mk III Ketch
Description
The Irwin 37 Mk III Ketch, produced from 1974 to 1979, is a spacious, comfortable center-cockpit cruising boat designed by Ted Irwin with a reputation for roomy interiors and respectable performance under sail for its era. Featuring a ketch rig (main + mizzen) that makes sail handling easy and provides flexible sail plans in heavy weather, it has a moderate-displacement hull (approximately 20,000 lbs displacement, 8,000 lbs ballast) with a shoal-draft keel (typically 5′ 4″) or optional deeper fin, a long waterline, and a relatively high ballast/displacement ratio that gives it reasonable stiffness. Below decks, the layout is notably voluminous for a 37-footer, offering a private aft stateroom with en-suite head, a large U-shaped galley, generous saloon, and a forward V-berth with second head, making it popular with liveaboard and family cruisers.
The standard boat dimensions
| i | 42 ft |
|---|---|
| j | 17.50 ft |
| p | 35.50 ft |
| e | 12.75 ft |
| p2 | 22.17 ft |
| e2 | 8.33 ft |
| i2 | - |
| j2 | - |
| I | J | P | E | P2 | E2 | I2 | J2 |
|---|---|---|---|---|---|---|---|
| 42 ft | 17.50 ft | 35.50 ft | 12.75 ft | 22.17 ft | 8.33 ft | - | - |
Sails
Irwin 37 Mk III Ketch - MAINSAIL
| Luff | * 35.5 ft - (10820 mm) |
|---|---|
| Foot | * 12.75 ft - (3886 mm) |
| Leech | * 37.02 ft - (11284 mm) |
| Tack Angle | * 88 ° |
| Diagonal | * 37.3 ft - (11369 mm) |
| Head (inches) | * 6 in - (152 mm) |
| Area | * 233.88 ft² |
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Irwin 37 Mk III Ketch - JIBSAIL
| Luff | * 36.4 ft - (11095 mm) |
|---|---|
| Foot | * 24.45 ft - (7452 mm) |
| Leech | * 30.19 ft - (9202 mm) |
| Percentage LP | * 114.97 % |
| Length Perpendicular | * 20.12 ft - (6133 mm) |
| Deck Angle | * 12 ° |
| Area | * 366.19 ft² |
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Irwin 37 Mk III Ketch - GENOA
| Luff | * 43.22 ft - (13173 mm) |
|---|---|
| Foot | * 29.36 ft - (8949 mm) |
| Leech | * 39.92 ft - (12168 mm) |
| Percentage LP | * 150 % |
| Length Perpendicular | * 26.25 ft - (8001 mm) |
| Deck Angle | * 3.98 ° |
| Area | * 567.31 ft² |
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Irwin 37 Mk III Ketch - ASYMMETRICAL
| Luff | * 43.22 ft - (13173 mm) |
|---|---|
| Foot | * 28.88 ft - (8803 mm) |
| Leech | * 39.76 ft - (12119 mm) |
| Perc LP | * 165 % |
| Area | * 936 ft² |
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Irwin 37 Mk III Ketch - SPINNAKER
| Stays | * 43.22 ft - (13173 mm) |
|---|---|
| MidGirth | * 31.5 ft - (9601 mm) |
| Foot | * 31.5 ft - (9601 mm) |
| Perc LP | * 180 % |
| Area | * 1157 ft² |
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Irwin 37 Mk III Ketch - STORMJIB
| Luff | * 25.02 ft - (7626 mm) |
|---|---|
| Foot | * 14.05 ft - (4282 mm) |
| Leech | * 18.87 ft - (5752 mm) |
| Perc LP | * 60 % |
| Length Perp | * 10.5 ft - (3200 mm) |
| Deck Angle | * 19.04 ° |
| Area | * 131.32 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.