The Thompson 850 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.
7.0 kts
A displacement hull pushes a bow wave whose speed is limited by the waterline length.
With a waterline of 27.6′, the Thompson 850 tops out around 7.0 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √27.6′ LWL = 7.0 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
51s/nm
Performance racer — quick around the cans and offshore.
Comfort Ratio
13.9
Quick, snappy motion — better for day sails and racing than long passages.
Capsize Screening
1.97
Below the 2.0 offshore threshold — acceptable for ocean passages.
Hull Speed
7.0kts
S# (Speed Number)
6.7
Pounds/Inch Immersion
756lbs
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
13.9
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
1.97
Below the 2.0 offshore threshold — acceptable for ocean passages.
Under 2.0 — Acceptable for offshore
Over 2.0 — Coastal / protected waters
PHRF Fleet Position
Where the Thompson 850 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Thompson 850
Performance racer — quick around the cans and offshore.
J/88
Tanzer 29
How It Compares
Side-by-side with the boats most often cross-shopped against the Thompson 850.
| Thompson 850 | First 277 Beneteau | J/88 | Merlin 29 Westerly | Regatta 290 Westerly | Tanzer 29 | |
|---|---|---|---|---|---|---|
| Dimensions | ||||||
| LOA | 29.0 | 29.0 | 29.0 | 29.0 | 29.0 | 29.0 |
| LWL | 27.6 | 27.2 | 25.0 | 23.6 | 23.0 | 24.3 |
| Beam | 7.7 | 9.8 | 10.2 | 9.9 | 9.9 | 10.3 |
| Displacement | 3 | 5 | 5 | 7 | 7 | 6 |
| Ballast | 1 | — | 2 | 2 | 3 | 2 |
| Sail Area | — | 448 | 436 | — | 330 | 403 |
| Performance | ||||||
| PHRF | 51 | — | 72 | — | — | 174 |
| SA/Disp | — | 23.0 | 24.0 | — | 13.6 | 18.6 |
| Bal/Disp | — | — | 42.3 | 38.8 | 43.3 | 37.3 |
| Comfort | 13.9 | 14.6 | 20.1 | — | 22.6 | 17.6 |
| Capsize | 1.97 | 2.23 | 1.75 | — | 2.01 | 2.20 |
| Hull Speed | 7.0 | 7.0 | 7.5 | — | 6.4 | 6.6 |