Foldsib 26
Description
The Foldsib 26 (likely a portmanteau of "Folding" + "Siberian" or "Sib" for its rugged, expedition-style build) is a custom or semi-custom folding trimaran sailboat designed by renowned multihull pioneer John Marples in the 1970s–1980s, inspired by his innovative Constant Camber (CC) 26 but adapted with enhanced folding mechanisms for superior trailering and coastal exploration. Drawing from Marples' constant camber construction technique—using a single curved plywood template for ultra-strong, eggshell-like hull panels—this 26-foot sloop-rigged trimaran emphasizes portability, speed, and simplicity, allowing the amas (outer hulls) to fold inward via hinged beams to a beam of just 8 feet for road transport behind a standard vehicle. Built by amateur or small-yard constructors using wood-epoxy composites, fewer than 100 were likely completed worldwide, making it a rare gem for blue water dreamers who value multihull performance without the bulk. Marples, through his firm Marples Marine, refined the design for durability in varied conditions, from Pacific trades to Northern European chop—proving its mettle in transoceanic passages.
The standard boat dimensions
| i | 27 ft |
|---|---|
| j | 9.60 ft |
| p | 27.20 ft |
| e | 11.70 ft |
| p2 | - |
| e2 | - |
| i2 | - |
| j2 | - |
| I | J | P | E | P2 | E2 | I2 | J2 |
|---|---|---|---|---|---|---|---|
| 27 ft | 9.60 ft | 27.20 ft | 11.70 ft | - | - | - | - |
Sails
Foldsib 26 - MAINSAIL
| Luff | 27.2 ft - (8291 mm) |
|---|---|
| Foot | 11.67 ft - (3557 mm) |
| Leech | * 29.05 ft - (8854 mm) |
| Tack Angle | * 87.99 ° |
| Diagonal | * 29.22 ft - (8906 mm) |
| Head (inches) | * 5.25 in - (133 mm) |
| Area | 158.51 ft² |
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Foldsib 26 - JIBSAIL
| Luff | 23.83 ft - (7263 mm) |
|---|---|
| Foot | 12.17 ft - (3709 mm) |
| Leech | 16.33 ft - (4977 mm) |
| Length Perpendicular | 7.7 ft - (2347 mm) |
| Area | 91.7 ft² |
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Foldsib 26 - GENOA
| Luff | 26.5 ft - (8077 mm) |
|---|---|
| Foot | 16.42 ft - (5005 mm) |
| Leech | 23.33 ft - (7111 mm) |
| Length Perpendicular | 14.3 ft - (4359 mm) |
| Area | 189.49 ft² |
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Foldsib 26 - SPINNAKER
| Stays | 27 ft - (8230 mm) |
|---|---|
| MidGirth | 18 ft - (5486 mm) |
| Foot | 18 ft - (5486 mm) |
| Area | 413.1 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.