San Juan 21 vs San Juan 34
How do the San Juan 21 and San Juan 34 compare? Below, their dimensions, displacement, sail area and the standard design ratios side by side, followed by a data-driven summary.
San Juan 21 
San Juan 34 | San Juan 21 | San Juan 34 | |
|---|---|---|
| Length overall | 20.5 ft6.25 m | 33.8 ft10.30 m |
| Waterline length | 17.5 ft5.33 m | 27.9 ft8.51 m |
| Beam | 7.0 ft2.13 m | 10.9 ft3.33 m |
| Draft | 4.0 ft1.22 m | 5.9 ft1.80 m |
| Displacement | 1,250 lb567 kg | 10,500 lb4,763 kg |
| Ballast | 400 lb181 kg | 4,800 lb2,177 kg |
| Sail area | 193 ft²17.9 m² | 551 ft²51.2 m² |
| SA / Displacement | 26.61 | 18.39 |
| Displacement / Length | 104 | 215 |
| Comfort ratio | 7.9 | 22.6 |
| Capsize screening | 2.60 | 1.99 |
| Hull speed (kn) | 5.6 | 7.1 |
San Juan 21 vs San Juan 34: the short version
- The San Juan 34 is the larger boat at 33.8 ft10.30 m LOA versus 20.5 ft6.25 m for the San Juan 21.
- The San Juan 34 is heavier, displacing about 740% more, which usually means a steadier but slower-to-accelerate hull.
- On sail area/displacement the San Juan 21 carries the more powerful rig (26.6 vs 18.4), favouring lighter-air performance.
- The San Juan 34 scores higher on the Brewer comfort ratio, suggesting an easier motion in a seaway.
- By the capsize screening formula the San Juan 34 rates better for offshore work (1.99 vs 2.60).
Ratios are guidelines computed from published specs; condition, layout and gear matter as much as the numbers.