Swan 39 vs Swan 391
How do the Swan 39 and Swan 391 compare? Below, their dimensions, displacement, sail area and the standard design ratios side by side, followed by a data-driven summary.
Swan 39 
Swan 391 | Swan 39 | Swan 391 | |
|---|---|---|
| Length overall | 31.5 ft9.60 m | 33.1 ft10.08 m |
| Waterline length | 31.5 ft9.60 m | 33.1 ft10.08 m |
| Beam | 12.5 ft3.81 m | 12.4 ft3.79 m |
| Draft | 7.2 ft2.19 m | 7.2 ft2.19 m |
| Displacement | 18,001 lb8,165 kg | 18,900 lb8,573 kg |
| Ballast | 7,900 lb3,583 kg | 6,800 lb3,084 kg |
| Sail area | 761 ft²70.7 m² | 767 ft²71.3 m² |
| SA / Displacement | 17.73 | 17.30 |
| Displacement / Length | 257 | 233 |
| Comfort ratio | 30.6 | 30.8 |
| Capsize screening | 1.91 | 1.87 |
| Hull speed (kn) | 7.5 | 7.7 |
Swan 39 vs Swan 391: the short version
- The Swan 391 is the larger boat at 33.1 ft10.08 m LOA versus 31.5 ft9.60 m for the Swan 39.
- On sail area/displacement the Swan 39 carries the more powerful rig (17.7 vs 17.3), favouring lighter-air performance.
- The Swan 391 scores higher on the Brewer comfort ratio, suggesting an easier motion in a seaway.
- By the capsize screening formula the Swan 391 rates better for offshore work (1.87 vs 1.91).
Ratios are guidelines computed from published specs; condition, layout and gear matter as much as the numbers.