Hull Speed
The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.
5.3 kts
A displacement hull pushes a bow wave whose speed is limited by the waterline length.
With a waterline of 15.5′, the Aurora 21 tops out around 5.3 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √15.5′ LWL = 5.3 kts
Performance Ratios
Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.
Ballast / Displacement
29.4%
Light ballast — tends to be tender; reef earlier than the numbers suggest.
Displacement / Length
204
Moderate — a good balance of speed and load-carrying ability.
Hull Speed
5.3kts
Pounds/Inch Immersion
2lbs
Weight needed to sink the hull one inch — loading sensitivity.
PHRF Fleet Position
Where the Aurora 21 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Venture 21
South Coast 21
Victory 21
How It Compares
Side-by-side with the boats most often cross-shopped against the Aurora 21.
| Aurora 21 | South Coast 21 | Varianta | Venture 21 | Victory 21 | Windward 21 Luger | |
|---|---|---|---|---|---|---|
| Dimensions | ||||||
| LOA | 21.0 | 21.0 | 21.0 | 21.0 | 21.0 | 21.0 |
| LWL | 15.5 | 14.3 | 17.7 | 18.5 | 15.0 | 19.5 |
| Beam | 6.3 | 6.9 | 6.9 | 6.8 | 6.3 | 8.0 |
| Displacement | 1 | 2 | 1 | 1 | 1 | 1 |
| Ballast | 500 | 625 | 573 | 400 | 500 | — |
| Sail Area | — | 206 | — | — | 185 | — |
| Performance | ||||||
| PHRF | — | 258 | — | 252 | 276 | — |
| SA/Disp | — | 20.8 | — | — | 24.3 | — |
| Bal/Disp | 29.4 | 31.3 | 44.1 | 26.7 | 37.0 | — |
| Comfort | — | 14.4 | — | — | 10.8 | — |
| Capsize | — | 2.20 | — | — | 2.26 | — |
| Hull Speed | — | 5.1 | — | — | 5.2 | — |