Hull Speed
The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.
4.2 kts
A displacement hull pushes a bow wave whose speed is limited by the waterline length.
With a waterline of 10.0′, the Montgomery 12 tops out around 4.2 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √10.0′ LWL = 4.2 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
65
Ultralight — responsive and fast, but carries less stores.
Hull Speed
4.2kts
Pounds/Inch Immersion
1lbs
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 Montgomery 12.
| Montgomery 12 | Butterfly | Dyer Dhow 12 12 | Oday 12 | Petrel 12 Rhodes | Tech Dinghy | |
|---|---|---|---|---|---|---|
| Dimensions | ||||||
| LOA | 12.2 | 12.0 | 12.5 | 12.3 | 12.0 | 12.0 |
| LWL | 10.0 | — | — | 11.5 | — | — |
| Beam | 4.8 | 4.5 | 5.0 | 5.0 | 5.0 | 4.7 |
| Displacement | 145 | 137 | 195 | 243 | 225 | 250 |
| Sail Area | — | 75 | 91 | 75 | 100 | 72 |
| Performance | ||||||
| SA/Disp | — | 45.2 | 43.3 | 30.8 | 43.3 | 29.1 |
| Comfort | — | 2.6 | 3.1 | 3.7 | 3.8 | — |
| Capsize | — | 3.49 | 3.45 | 3.21 | — | 2.97 |
| Hull Speed | — | 4.3 | 4.4 | 4.5 | 4.3 | — |