Swan 39 vs Swan 46 Mk III
How do the Swan 39 and Swan 46 Mk III compare? Below, their dimensions, displacement, sail area and the standard design ratios side by side, followed by a data-driven summary.
Swan 39 
Swan 46 Mk III | Swan 39 | Swan 46 Mk III | |
|---|---|---|
| Length overall | 31.5 ft9.60 m | 46.6 ft14.20 m |
| Waterline length | 31.5 ft9.60 m | 39.6 ft12.06 m |
| Beam | 12.5 ft3.81 m | 14.0 ft4.26 m |
| Draft | 7.2 ft2.19 m | 7.2 ft2.20 m |
| Displacement | 18,001 lb8,165 kg | 32,408 lb14,700 kg |
| Ballast | 7,900 lb3,583 kg | 12,125 lb5,500 kg |
| Sail area | 761 ft²70.7 m² | 1,179 ft²109.5 m² |
| SA / Displacement | 17.73 | 18.56 |
| Displacement / Length | 257 | 234 |
| Comfort ratio | 30.6 | 35.8 |
| Capsize screening | 1.91 | 1.75 |
| Hull speed (kn) | 7.5 | 8.4 |
Swan 39 vs Swan 46 Mk III: the short version
- The Swan 46 Mk III is the larger boat at 46.6 ft14.20 m LOA versus 31.5 ft9.60 m for the Swan 39.
- The Swan 46 Mk III is heavier, displacing about 80% more, which usually means a steadier but slower-to-accelerate hull.
- On sail area/displacement the Swan 46 Mk III carries the more powerful rig (18.6 vs 17.7), favouring lighter-air performance.
- The Swan 46 Mk III scores higher on the Brewer comfort ratio, suggesting an easier motion in a seaway.
- By the capsize screening formula the Swan 46 Mk III rates better for offshore work (1.75 vs 1.91).
Ratios are guidelines computed from published specs; condition, layout and gear matter as much as the numbers.