The Seamaster 47 is modestly canvassed and unhurried, with a steady, comfortable ride offshore.
Hull Speed
The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.
A displacement hull pushes a bow wave whose speed is limited by the waterline length.
With a waterline of 34.0′, the Seamaster 47 tops out around 7.8 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √34.0′ LWL = 7.8 kts
Performance Ratios
Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.
SA / Displacement
12.1
Modestly canvassed — a comfortable, unhurried cruiser.
Comfort Ratio
35.6
Good offshore comfort — steady enough for multi-day passages.
Capsize Screening
1.76
Below the 2.0 offshore threshold — acceptable for ocean passages.
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
35.6
Good offshore comfort — steady enough for multi-day passages.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
1.76
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 Seamaster 47 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Racer 0–90
Cruiser/Racer 90–150
Cruiser 150–210
Valiant 47
92s/nm
Hylas 47
93s/nm
Ct 47
111s/nm
Estimated Speed by Wind
Rough boat speed estimates at different true wind speeds and points of sail — derived from hull speed, SA/D, and displacement, not measured polars.
| Point of Sail |
6 kts TWS |
10 kts TWS |
15 kts TWS |
20 kts TWS |
| Close-hauled40–50° |
2.7 |
3.4 |
3.8 |
3.9 |
| Close Reach60° |
3.2 |
4.1 |
4.6 |
4.8 |
| Beam Reach90° |
4.0 |
5.0 |
5.6 |
5.8 |
| Broad Reach120–135° |
3.7 |
4.6 |
5.2 |
5.4 |
| Run150–180° |
2.9 |
3.7 |
4.1 |
4.3 |
These are simplified estimates based on hull speed (7.8 kts),
SA/D (12.1), and empirical efficiency curves — not instrument-measured
polars. Real-world speed varies with sea state, bottom condition, sail trim, and current.
Speeds in gold approach hull speed;
bold gold means near or at hull speed.
Wind Range & Comfort Envelope
Estimated wind ranges for comfortable sailing on the Seamaster 47 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–8 kts
8–22 kts
22–30 kts
30+ kts
Ghosting
0–8 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
8–22 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
22–30 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
30+ kts
Storm conditions. Storm jib or bare poles. Seek shelter if coastal.
How It Compares
Side-by-side with the boats most often cross-shopped against the Seamaster 47.
|
Seamaster 47 |
Ct 47 |
Gulfstar 47 Sailmaster |
Hylas 47 |
Tayana 47 Cc |
Valiant 47 |
| Dimensions |
| LOA |
47.2 |
46.9 |
47.4 |
46.8 |
47.0 |
47.0 |
| LWL |
34.0 |
37.5 |
40.5 |
37.8 |
40.3 |
40.0 |
| Beam |
13.3 |
13.2 |
13.8 |
14.3 |
14.5 |
13.8 |
| Displacement |
27 |
29 |
38 |
35 |
35 |
30 |
| Ballast |
8 |
12 |
10 |
14 |
11 |
11 |
| Sail Area |
680 |
908 |
923 |
1 |
1 |
— |
| Performance |
| PHRF |
— |
111 |
— |
93 |
— |
92 |
| SA/Disp |
12.1 |
15.3 |
13.1 |
15.8 |
20.7 |
— |
| Bal/Disp |
— |
40.8 |
27.6 |
41.7 |
33.4 |
36.7 |
| Comfort |
35.6 |
36.4 |
41.7 |
38.9 |
36.4 |
— |
| Capsize |
1.76 |
1.71 |
1.65 |
1.75 |
1.78 |
— |
| Hull Speed |
7.8 |
8.2 |
8.5 |
8.2 |
8.5 |
— |