The Nacra Inter 18 is with a quick, snappy motion best suited to day sailing.
Hull Speed
The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.
5.7 kts
A displacement hull pushes a bow wave whose speed is limited by the waterline length.
With a waterline of 18.1′, the Nacra Inter 18 tops out around 5.7 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √18.1′ LWL = 5.7 kts
Performance Ratios
Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.
Comfort Ratio
2.0
Quick, snappy motion — better for day sails and racing than long passages.
Capsize Screening
4.63
Above the 2.0 offshore threshold — best suited for coastal and protected waters.
Hull Speed
5.7kts
Pounds/Inch Immersion
3lbs
Weight needed to sink the hull one inch — loading sensitivity.
Motion & Offshore Suitability
Two ratios that matter most when you're planning passages — how the boat feels in a seaway, and whether the hull geometry is suitable for open ocean.
Comfort Ratio
2.0
Quick, snappy motion — better for day sails and racing than long passages.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
4.63
Above the 2.0 offshore threshold — best suited for coastal and protected waters.
Under 2.0 — Acceptable for offshore
Over 2.0 — Coastal / protected waters
How It Compares
Side-by-side with the boats most often cross-shopped against the Nacra Inter 18.
| Nacra Inter 18 | Dart 18 | Hobie 18 Magnum | Hobie Tiger 18 | Prindle 18 | Prindle 18 2 | |
|---|---|---|---|---|---|---|
| Dimensions | ||||||
| LOA | 18.1 | 18.0 | 18.0 | 18.1 | 18.0 | 18.0 |
| LWL | 18.1 | 17.0 | — | — | 17.0 | 17.2 |
| Beam | 8.5 | 7.5 | 8.0 | 8.5 | 7.9 | 8.5 |
| Displacement | 397 | 285 | 440 | 397 | 335 | 375 |
| Sail Area | 220 | 175 | 240 | 220 | 218 | 233 |
| Performance | ||||||
| SA/Disp | — | 64.7 | 66.5 | 65.2 | 72.4 | — |
| Comfort | 2.0 | 1.7 | 2.6 | 2.2 | — | 1.9 |
| Capsize | 4.63 | 4.56 | 4.21 | 4.65 | — | 4.72 |
| Hull Speed | 5.7 | 5.5 | 5.2 | 5.3 | — | 5.6 |