The Cape George 31 is moderately powered for comfortable coastal cruising, with a gentle bluewater motion.
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 27.5′, the Cape George 31 tops out around 7.0 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √27.5′ 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
218s/nm
Heavy or slow cruiser — all about the journey, not the elapsed time.
SA / Displacement
16.2
Moderate sail power — a capable coastal cruiser, not overpowered.
Ballast / Displacement
49.3%
Race-oriented ballast ratio — very stiff and powerful.
Displacement / Length
340
Moderate-heavy — carries provisions well, deliberate in light air.
Comfort Ratio
42.3
Very comfortable in a seaway — a genuine bluewater motion.
Capsize Screening
1.53
Below the 2.0 offshore threshold — acceptable for ocean passages.
Pounds/Inch Immersion
6lbs
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
42.3
Very comfortable in a seaway — a genuine bluewater motion.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
1.53
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 Cape George 31 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Cruiser/Racer 90–150
Cruiser 150–210
Heavy Cruiser 210–300
Island Packet 31
186s/nm
Cape George 31
218s/nm
Heavy or slow cruiser — all about the journey, not the elapsed time.
Bombay Clipper 31
234s/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 |
3.5 |
3.9 |
4.0 |
| Close Reach60° |
3.3 |
4.2 |
4.7 |
4.9 |
| Beam Reach90° |
4.1 |
5.1 |
5.7 |
6.0 |
| Broad Reach120–135° |
3.7 |
4.7 |
5.3 |
5.5 |
| Run150–180° |
3.0 |
3.8 |
4.2 |
4.4 |
These are simplified estimates based on hull speed (7.0 kts),
SA/D (16.2), 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 Cape George 31 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–7 kts
7–22 kts
22–32 kts
32+ kts
Ghosting
0–7 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
7–22 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
22–32 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
32+ 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 Cape George 31.
|
Cape George 31 |
Bombay Clipper 31 |
Bristol 311 |
Island Packet 31 |
Offshore 31 Cheoy Lee |
Rival 31 |
| Dimensions |
| LOA |
31.0 |
31.0 |
31.0 |
31.0 |
31.0 |
31.0 |
| LWL |
27.5 |
25.6 |
24.8 |
27.8 |
23.3 |
24.5 |
| Beam |
9.6 |
11.0 |
10.2 |
11.6 |
8.8 |
9.7 |
| Displacement |
15 |
10 |
11 |
11 |
10 |
11 |
| Ballast |
7 |
3 |
4 |
4 |
3 |
4 |
| Sail Area |
634 |
419 |
455 |
530 |
403 |
— |
| Performance |
| PHRF |
218 |
234 |
— |
186 |
— |
— |
| SA/Disp |
16.2 |
14.5 |
14.6 |
17.2 |
13.3 |
— |
| Bal/Disp |
49.3 |
34.0 |
40.2 |
40.9 |
35.5 |
40.0 |
| Comfort |
42.3 |
23.3 |
29.6 |
22.6 |
35.9 |
31.9 |
| Capsize |
1.53 |
2.05 |
1.82 |
2.09 |
1.59 |
1.73 |
| Hull Speed |
7.0 |
6.8 |
6.7 |
7.1 |
6.5 |
6.6 |