Fireball vs Viper 640
How do the Fireball and Viper 640 compare? Below, their dimensions, displacement, sail area and the standard design ratios side by side, followed by a data-driven summary.
Fireball 
Viper 640 | Fireball | Viper 640 | |
|---|---|---|
| Length overall | 16.2 ft4.93 m | 21.1 ft6.43 m |
| Waterline length | 13.3 ft4.04 m | 19.1 ft5.82 m |
| Beam | 4.6 ft1.40 m | 8.2 ft2.49 m |
| Draft | 4.0 ft1.22 m | 4.5 ft1.37 m |
| Displacement | 170 lb77 kg | 750 lb340 kg |
| Ballast | —— | 262 lb119 kg |
| Sail area | 124 ft²11.5 m² | 211 ft²19.6 m² |
| SA / Displacement | 64.65 | 40.90 |
| Displacement / Length | 33 | 48 |
| Comfort ratio | 2.4 | 3.6 |
| Capsize screening | 3.31 | 3.60 |
| Hull speed (kn) | 4.9 | 5.9 |
Fireball vs Viper 640: the short version
- The Viper 640 is the larger boat at 21.1 ft6.43 m LOA versus 16.2 ft4.93 m for the Fireball.
- The Viper 640 is heavier, displacing about 341% more, which usually means a steadier but slower-to-accelerate hull.
- On sail area/displacement the Fireball carries the more powerful rig (64.7 vs 40.9), favouring lighter-air performance.
- The Viper 640 scores higher on the Brewer comfort ratio, suggesting an easier motion in a seaway.
- By the capsize screening formula the Fireball rates better for offshore work (3.31 vs 3.60).
Ratios are guidelines computed from published specs; condition, layout and gear matter as much as the numbers.