Block Island 40
Description
The Block Island 40 is a celebrated classic cruising yacht designed by William H. Tripp Jr. and first built by American Boatbuilding Company of East Greenwich, Rhode Island. Introduced in 1957, the design marked a turning point in yacht construction, being among the first series‑built fiberglass offshore sailboats—a bold move at a time when most bluewater yachts were still constructed of wood. The Block Island 40 quickly earned a reputation for its seaworthiness, beauty, and balanced performance, blending traditional lines with modern underbody efficiency. Production ran in several iterations from 1957 through the early 1970s, with roughly 60 to 65 hulls built across different marks (Mk I, II, and III).
Construction Details
| Designer | William Tripp, Jr |
|---|---|
| Builder | American Boat Building |
| Length | 40.000 ft |
| LOA | 40.000 ft |
| LWL | 27.500 ft |
| Beam | 11.750 ft |
| Displacement | 21000 lb |
| Max Draft | 8.420 ft |
| Min Draft | 3.920 ft |
The standard boat dimensions
| i | 44.70 ft |
|---|---|
| j | 15.70 ft |
| p | 38.50 ft |
| e | 17.50 ft |
| p2 | - |
| e2 | - |
| i2 | - |
| j2 | - |
| I | J | P | E | P2 | E2 | I2 | J2 |
|---|---|---|---|---|---|---|---|
| 44.70 ft | 15.70 ft | 38.50 ft | 17.50 ft | - | - | - | - |
Sails
Block Island 40 - MAINSAIL
| Luff | * 38.5 ft - (11735 mm) |
|---|---|
| Foot | * 17.5 ft - (5334 mm) |
| Leech | * 41.53 ft - (12658 mm) |
| Tack Angle | * 88 ° |
| Diagonal | * 41.73 ft - (12719 mm) |
| Head (inches) | * 6 in - (152 mm) |
| Area | * 346.21 ft² |
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Block Island 40 - JIBSAIL
| Luff | 37.9 ft - (11552 mm) |
|---|---|
| Foot | * 21.15 ft - (6447 mm) |
| Leech | * 32.39 ft - (9872 mm) |
| Percentage LP | * 115.03 % |
| Length Perpendicular | * 18.06 ft - (5505 mm) |
| Deck Angle | * 12.02 ° |
| Area | * 342.2 ft² |
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Block Island 40 - GENOA
| Luff | 45.01 ft - (13719 mm) |
|---|---|
| Foot | * 25.65 ft - (7818 mm) |
| Leech | * 42.06 ft - (12820 mm) |
| Percentage LP | * 150 % |
| Length Perpendicular | * 23.55 ft - (7178 mm) |
| Deck Angle | * 3.99 ° |
| Area | * 530.02 ft² |
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Block Island 40 - SPINNAKER
| Stays | * 45.01 ft - (13719 mm) |
|---|---|
| MidGirth | * 28.26 ft - (8614 mm) |
| Foot | * 28.26 ft - (8614 mm) |
| Perc LP | * 180 % |
| Area | * 1081 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.