Catalina 18 vs Catalina 310
How do the Catalina 18 and Catalina 310 compare? Below, their dimensions, displacement, sail area and the standard design ratios side by side, followed by a data-driven summary.
Catalina 18 
Catalina 310 | Catalina 18 | Catalina 310 | |
|---|---|---|
| Length overall | 18.0 ft5.49 m | 31.0 ft9.45 m |
| Waterline length | 16.3 ft4.98 m | 26.5 ft8.08 m |
| Beam | 7.6 ft2.31 m | 11.5 ft3.51 m |
| Draft | 2.3 ft0.71 m | 5.8 ft1.75 m |
| Displacement | 1,500 lb680 kg | 10,300 lb4,672 kg |
| Ballast | 425 lb193 kg | 4,000 lb1,814 kg |
| Sail area | 151 ft²14.0 m² | 493 ft²45.8 m² |
| SA / Displacement | 18.44 | 16.66 |
| Displacement / Length | 154 | 247 |
| Comfort ratio | 9.3 | 22.1 |
| Capsize screening | 2.65 | 2.11 |
| Hull speed (kn) | 5.4 | 6.9 |
Catalina 18 vs Catalina 310: the short version
- The Catalina 310 is the larger boat at 31.0 ft9.45 m LOA versus 18.0 ft5.49 m for the Catalina 18.
- The Catalina 310 is heavier, displacing about 587% more, which usually means a steadier but slower-to-accelerate hull.
- On sail area/displacement the Catalina 18 carries the more powerful rig (18.4 vs 16.7), favouring lighter-air performance.
- The Catalina 310 scores higher on the Brewer comfort ratio, suggesting an easier motion in a seaway.
- By the capsize screening formula the Catalina 310 rates better for offshore work (2.11 vs 2.65).
Ratios are guidelines computed from published specs; condition, layout and gear matter as much as the numbers.