Hull Speed
The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.
4.9 kts
A displacement hull pushes a bow wave whose speed is limited by the waterline length.
With a waterline of 13.2′, the 420 tops out around 4.9 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √13.2′ LWL = 4.9 kts
Performance Ratios
Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.
Displacement / Length
43
Ultralight — responsive and fast, but carries less stores.
Hull Speed
4.9kts
Pounds/Inch Immersion
2lbs
Weight needed to sink the hull one inch — loading sensitivity.
How It Compares
Side-by-side with the boats most often cross-shopped against the 420.
| 420 | Flying Tern | Force 5 | Ilca 6 Laser Radial | Ilca 7 Laser International | Javelin 14 Fox | |
|---|---|---|---|---|---|---|
| Dimensions | ||||||
| LOA | 13.8 | 13.9 | 13.9 | 13.9 | 13.9 | 14.0 |
| LWL | 13.2 | — | 13.2 | 12.5 | 12.5 | 13.2 |
| Beam | 5.4 | 5.1 | 4.8 | 4.5 | 4.5 | 5.7 |
| Displacement | 220 | 287 | 140 | 128 | 128 | 475 |
| Ballast | — | — | — | — | — | 49 |
| Sail Area | — | 120 | 91 | 62 | 76 | 125 |
| Performance | ||||||
| SA/Disp | — | 44.2 | 54.0 | 39.1 | 47.9 | 32.9 |
| Bal/Disp | — | — | — | — | — | 10.3 |
| Comfort | — | — | 2.0 | 2.1 | 2.1 | 5.4 |
| Capsize | — | 3.09 | 3.72 | 3.56 | 3.56 | 2.91 |
| Hull Speed | — | — | 4.9 | 4.7 | 4.7 | 4.9 |