Nacra 55 18 Sq Meter Performance

Hull Speed

The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.

5.2 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

41

Ultralight — responsive and fast, but carries less stores.

Comfort Ratio

1.3

Quick, snappy motion — better for day sails and racing than long passages.

Capsize Screening

6.37

Above the 2.0 offshore threshold — best suited for coastal and protected waters.

Hull Speed

5.2kts

Pounds/Inch Immersion

4lbs

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

1.3

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

6.37

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 55 18 Sq Meter.

	Nacra 55 18 Sq Meter	A Class Catamaran	Dart 18	Hobie 18 Magnum	Prindle 18	Prindle 18 2
Dimensions
LOA	18.0	18.0	18.0	18.0	18.0	18.0
LWL	—	18.0	17.0	—	17.0	17.2
Beam	11.0	7.5	7.5	8.0	7.9	8.5
Displacement	330	165	285	440	335	375
Sail Area	193	150	175	240	218	233
Performance
SA/Disp	—	79.8	64.7	66.5	72.4	—
Comfort	1.3	1.0	1.7	2.6	—	1.9
Capsize	6.37	5.49	4.56	4.21	—	4.72
Hull Speed	5.2	5.7	5.5	5.2	—	5.6