The Thompson 30 is with a quick, snappy motion best suited to day sailing, and competitive on the racecourse.
Hull Speed
The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.
7.2 kts
A displacement hull pushes a bow wave whose speed is limited by the waterline length.
With a waterline of 29.2′, the Thompson 30 tops out around 7.2 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √29.2′ LWL = 7.2 kts
Performance Ratios
Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.
PHRF Rating
36s/nm
Performance racer — quick around the cans and offshore.
Ballast / Displacement
60.0%
Race-oriented ballast ratio — very stiff and powerful.
Displacement / Length
59
Ultralight — responsive and fast, but carries less stores.
Comfort Ratio
7.8
Quick, snappy motion — better for day sails and racing than long passages.
Capsize Screening
2.74
Above the 2.0 offshore threshold — best suited for coastal and protected waters.
Hull Speed
7.2kts
Pounds/Inch Immersion
1lbs
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
7.8
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
2.74
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
PHRF Fleet Position
Where the Thompson 30 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Thompson 30
Performance racer — quick around the cans and offshore.
Harbor 30
Catalina 309
How It Compares
Side-by-side with the boats most often cross-shopped against the Thompson 30.
| Thompson 30 | Catalina 309 | F 31 Sport Cruiser | Harbor 30 | Sun Fast 30 Od Jeanneau | Z 30 | |
|---|---|---|---|---|---|---|
| Dimensions | ||||||
| LOA | 30.7 | 30.8 | 30.8 | 30.8 | 30.5 | 30.7 |
| LWL | 29.2 | 26.0 | 30.0 | 26.1 | 26.6 | — |
| Beam | 10.2 | 11.0 | 22.4 | 9.9 | 10.5 | 10.7 |
| Displacement | 3 | 9 | 3 | 7 | 7 | 5 |
| Ballast | 1 | 3 | — | 3 | 3 | 3 |
| Sail Area | — | 452 | 599 | 523 | 484 | — |
| Performance | ||||||
| PHRF | 36 | 167 | — | 120 | — | — |
| SA/Disp | — | 16.4 | 40.7 | 21.9 | 19.4 | — |
| Bal/Disp | 60.0 | 41.3 | — | 44.0 | 40.3 | 56.7 |
| Comfort | 7.8 | 21.1 | — | 19.8 | 19.2 | 13.6 |
| Capsize | 2.74 | 2.10 | — | 2.03 | 2.11 | — |
| Hull Speed | 7.2 | 6.8 | — | 6.9 | 6.9 | 6.8 |