Swan 391 vs Swan 40
How do the Swan 391 and Swan 40 compare? Below, their dimensions, displacement, sail area and the standard design ratios side by side, followed by a data-driven summary.
Swan 391 
Swan 40 | Swan 391 | Swan 40 | |
|---|---|---|
| Length overall | 33.1 ft10.08 m | 39.3 ft11.98 m |
| Waterline length | 33.1 ft10.08 m | 28.5 ft8.70 m |
| Beam | 12.4 ft3.79 m | 10.8 ft3.30 m |
| Draft | 7.2 ft2.19 m | 6.7 ft2.05 m |
| Displacement | 18,900 lb8,573 kg | 18,960 lb8,600 kg |
| Ballast | 6,800 lb3,084 kg | 7,900 lb3,583 kg |
| Sail area | 767 ft²71.3 m² | 709 ft²65.9 m² |
| SA / Displacement | 17.30 | 15.95 |
| Displacement / Length | 233 | 364 |
| Comfort ratio | 30.8 | 38.6 |
| Capsize screening | 1.87 | 1.62 |
| Hull speed (kn) | 7.7 | 7.2 |
Swan 391 vs Swan 40: the short version
- The Swan 40 is the larger boat at 39.3 ft11.98 m LOA versus 33.1 ft10.08 m for the Swan 391.
- On sail area/displacement the Swan 391 carries the more powerful rig (17.3 vs 16.0), favouring lighter-air performance.
- The Swan 40 scores higher on the Brewer comfort ratio, suggesting an easier motion in a seaway.
- By the capsize screening formula the Swan 40 rates better for offshore work (1.62 vs 1.87).
Ratios are guidelines computed from published specs; condition, layout and gear matter as much as the numbers.