Thomas 1/4 Ton
Description
The Thomas 1/4 Ton is a 25-foot International Offshore Rule (IOR) Quarter Ton class racing sailboat designed in the mid-1970s by prominent British yacht designer David Thomas (1932–2014), known for his successful club and offshore racers including the Sigma series and Hunter models. The prototype, Purple Haze (launched 1977), served as the basis for the production Bolero model; individual boats were built as one-offs or small runs, often in cold-molded wood (such as mahogany by builders like Bob Hoare) or early GRP with marine plywood options, with examples like Quarto (plywood) and Cascade competing in Quarter Ton Cups in the 1970s. Exact production quantity is not well documented in public records but appears limited to a handful of custom and semi-custom builds rather than large-scale series production. These boats emphasized light-air performance, a sleek low-freeboard hull, and competitive IOR optimization for club racing and events like the revived Quarter Ton Cup.
Construction Details
| Designer | David Thomas |
|---|---|
| Builder | One-offs or small runs |
| Length | 25.000 ft |
| LOA | 25.000 ft |
| LWL | 19.830 ft |
| Beam | 9.000 ft |
| Displacement | 2800 lb |
| Ballast | 1550 lb |
| Year Built | 1977 |
The standard boat dimensions
| i | 35.25 ft |
|---|---|
| j | 11.25 ft |
| p | 30.75 ft |
| e | 10.75 ft |
| p2 | - |
| e2 | - |
| i2 | - |
| j2 | - |
| I | J | P | E | P2 | E2 | I2 | J2 |
|---|---|---|---|---|---|---|---|
| 35.25 ft | 11.25 ft | 30.75 ft | 10.75 ft | - | - | - | - |
Sails
Thomas 1/4 Ton - MAINSAIL
| Luff | * 30.75 ft - (9373 mm) |
|---|---|
| Foot | * 10.75 ft - (3277 mm) |
| Leech | * 32.1 ft - (9784 mm) |
| Tack Angle | * 88.01 ° |
| Diagonal | * 32.22 ft - (9821 mm) |
| Head (inches) | * 4.5 in - (114 mm) |
| Area | 165.1 ft² |
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Thomas 1/4 Ton - JIBSAIL
| Luff | * 29.6 ft - (9022 mm) |
|---|---|
| Foot | * 14.89 ft - (4538 mm) |
| Leech | * 25.71 ft - (7836 mm) |
| Percentage LP | * 115 % |
| Length Perpendicular | * 12.94 ft - (3944 mm) |
| Deck Angle | * 12 ° |
| Area | 191.4 ft² |
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Thomas 1/4 Ton - GENOA
| Luff | * 35.15 ft - (10714 mm) |
|---|---|
| Foot | * 18.16 ft - (5535 mm) |
| Leech | * 33.06 ft - (10077 mm) |
| Percentage LP | * 150 % |
| Length Perpendicular | * 16.88 ft - (5145 mm) |
| Deck Angle | * 4 ° |
| Area | 296.51 ft² |
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Thomas 1/4 Ton - SPINNAKER
| Stays | * 35.15 ft - (10714 mm) |
|---|---|
| MidGirth | * 20.25 ft - (6172 mm) |
| Foot | * 20.25 ft - (6172 mm) |
| Perc LP | * 180 % |
| Area | 605.02 ft² |
| Edit in Calculator |
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.
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