The Iso Dinghy 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.
4.9 kts
A displacement hull pushes a bow wave whose speed is limited by the waterline length.
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.
Comfort Ratio
2.4
Quick, snappy motion — better for day sails and racing than long passages.
Hull Speed
4.9kts
Pounds/Inch Immersion
2lbs
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
2.4
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
How It Compares
Side-by-side with the boats most often cross-shopped against the Iso Dinghy.
| Iso Dinghy | 470 | Snipe | Vanguard 15 | Wayfarer | Windmill | |
|---|---|---|---|---|---|---|
| Dimensions | ||||||
| LOA | 15.6 | 15.4 | 15.5 | 15.3 | 15.8 | 15.5 |
| LWL | — | 14.6 | 12.7 | 15.0 | 14.8 | 14.5 |
| Beam | 5.7 | 5.5 | 5.0 | 5.5 | 6.1 | 4.8 |
| Displacement | 220 | 269 | 380 | 200 | 372 | 198 |
| Sail Area | 152 | 137 | 128 | 127 | 141 | 119 |
| Performance | ||||||
| SA/Disp | — | 52.7 | 39.1 | 59.5 | 43.7 | 56.1 |
| Comfort | 2.4 | 2.9 | 5.1 | 2.1 | 3.4 | 2.6 |
| Capsize | — | 3.41 | 2.76 | 3.76 | 3.38 | 3.26 |
| Hull Speed | 4.9 | 5.1 | 4.8 | 5.2 | 5.2 | 5.1 |