Swan 391 vs Swan 55
How do the Swan 391 and Swan 55 compare? Below, their dimensions, displacement, sail area and the standard design ratios side by side, followed by a data-driven summary.
Swan 391 
Swan 55 | Swan 391 | Swan 55 | |
|---|---|---|
| Length overall | 33.1 ft10.08 m | 54.6 ft16.65 m |
| Waterline length | 33.1 ft10.08 m | 38.5 ft11.73 m |
| Beam | 12.4 ft3.79 m | 14.2 ft4.33 m |
| Draft | 7.2 ft2.19 m | 8.5 ft2.60 m |
| Displacement | 18,900 lb8,573 kg | 45,636 lb20,700 kg |
| Ballast | 6,800 lb3,084 kg | 17,000 lb7,711 kg |
| Sail area | 767 ft²71.3 m² | 1,277 ft²118.6 m² |
| SA / Displacement | 17.30 | 16.00 |
| Displacement / Length | 233 | 358 |
| Comfort ratio | 30.8 | 47.5 |
| Capsize screening | 1.87 | 1.59 |
| Hull speed (kn) | 7.7 | 8.3 |
Swan 391 vs Swan 55: the short version
- The Swan 55 is the larger boat at 54.6 ft16.65 m LOA versus 33.1 ft10.08 m for the Swan 391.
- The Swan 55 is heavier, displacing about 141% more, which usually means a steadier but slower-to-accelerate hull.
- On sail area/displacement the Swan 391 carries the more powerful rig (17.3 vs 16.0), favouring lighter-air performance.
- The Swan 55 scores higher on the Brewer comfort ratio, suggesting an easier motion in a seaway.
- By the capsize screening formula the Swan 55 rates better for offshore work (1.59 vs 1.87).
Ratios are guidelines computed from published specs; condition, layout and gear matter as much as the numbers.