The Westerly 21 is moderately powered for comfortable coastal cruising, with a quick, snappy motion best suited to day sailing.
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 18.8′, the Westerly 21 tops out around 5.8 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √18.8′ LWL = 5.8 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
14.2
Moderate sail power — a capable coastal cruiser, not overpowered.
Ballast / Displacement
45.8%
Race-oriented ballast ratio — very stiff and powerful.
Displacement / Length
248
Moderate — a good balance of speed and load-carrying ability.
Comfort Ratio
18.9
Quick, snappy motion — better for day sails and racing than long passages.
Capsize Screening
2.01
Above the 2.0 offshore threshold — best suited for coastal and protected waters.
Pounds/Inch Immersion
519lbs
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
18.9
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
2.01
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 Westerly 21 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Cruiser 150–210
Heavy Cruiser 210–300
Cs 22
249s/nm
Hunter 22
252s/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° |
2.1 |
2.7 |
3.0 |
3.1 |
| Close Reach60° |
2.6 |
3.2 |
3.6 |
3.8 |
| Beam Reach90° |
3.2 |
4.0 |
4.5 |
4.6 |
| Broad Reach120–135° |
2.9 |
3.7 |
4.1 |
4.3 |
| Run150–180° |
2.3 |
2.9 |
3.3 |
3.4 |
These are simplified estimates based on hull speed (5.8 kts),
SA/D (14.2), 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 Westerly 21 — 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 Westerly 21.
|
Westerly 21 |
Chrysler 22 Fk |
Cs 22 |
Etap 22 |
Hunter 22 |
Jaguar 22 |
| Dimensions |
| LOA |
21.5 |
21.6 |
21.6 |
21.7 |
21.5 |
21.5 |
| LWL |
18.8 |
19.0 |
17.5 |
18.7 |
18.5 |
19.3 |
| Beam |
7.8 |
7.8 |
8.0 |
7.9 |
8.0 |
7.7 |
| Displacement |
3 |
3 |
2 |
2 |
2 |
2 |
| Ballast |
1 |
725 |
1 |
1 |
1 |
550 |
| Sail Area |
210 |
— |
— |
— |
213 |
205 |
| Performance |
| PHRF |
— |
— |
249 |
— |
252 |
— |
| SA/Disp |
14.2 |
— |
— |
— |
17.8 |
19.2 |
| Bal/Disp |
45.8 |
— |
50.0 |
44.0 |
37.7 |
24.4 |
| Comfort |
18.9 |
15.3 |
— |
— |
13.1 |
11.5 |
| Capsize |
2.01 |
2.15 |
— |
— |
2.32 |
2.34 |
| Hull Speed |
5.8 |
5.8 |
— |
— |
5.8 |
5.9 |