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Westerly 21
Designer: Laurent Giles  ·  Builder: Westerly Yachts Ltd. (Uk)  ·  First built: 1977
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About the Westerly 21

Designed by the prestigious Laurent Giles studio and built by Westerly Yachts between 1977 and 1979, this compact cruiser represents British boatbuilding at its most practical. With only 53 hulls produced during its brief three-year run, the Westerly 21 has become a sought-after example of quality fiberglass construction from one of the UK's most respected builders. The twin keel configuration stands as this boat's defining characteristic, offering the significant advantage of drying out upright in tidal harbors and accessing shallow cruising grounds that would challenge deeper-drafted vessels. This feature, combined with her modest 21-foot length, makes her ideally suited for coastal exploration and weekend cruising in areas with dramatic tidal ranges. Her masthead sloop rig provides straightforward sail handling, while the substantial ballast-to-displacement ratio of nearly 46% ensures reassuring stability despite her compact size. The comfort ratio of 18.88 suggests a relatively quick motion in a seaway, typical of smaller cruisers but manageable for coastal work. With a capsize screening value of 2.01, she falls within acceptable parameters for protected waters and moderate coastal conditions, though extended offshore passages would stretch her intended envelope.

Core Dimensions
LOA (Length Overall) 21.50 ft / 6.55 m
LWL (Waterline Length) 18.75 ft / 5.72 m
Beam 7.75 ft / 2.36 m
Max Draft 2.75 ft / 0.84 m
Displacement 3,660.00 lb / 1,660 kg
Ballast 1,675.00 lb / 760 kg
Sail Area (Reported) 210.00 ft² / 19.51 m²
Design & Construction
Hull Type Twin Keel
Rigging Type Masthead Sloop
Construction FG
Designer Laurent Giles
Builder Westerly Yachts Ltd. (UK)
First Built 1977
Last Built 1979
Number Built 53
Associations Westerly Owners Association
Related Sailboats Jaguar 22 · Etap 22 · Hunter 22 · Chrysler 22 Fk · Cs 22
Owner Reviews

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Performance Ratios
SA/Displacement Sail Area to Displacement ratio measures how much sail power a boat has relative to its weight. Higher values mean more performance and speed.
Under 14 — Heavy cruiser, slow14–18 — Cruising sailboat18–22 — Cruiser/racerOver 22 — Performance racer
14.19
Ballast/Displacement Ballast to Displacement ratio shows what percentage of the boat's total weight is ballast. Higher values generally mean better initial stability and stiffer sail carrying.
30–35% — Typical cruiser35–45% — Stiff performance boatOver 45% — Racing oriented
45.77
Displacement/Length Displacement to Length ratio measures how heavy a boat is relative to its waterline length. Lower values mean a lighter, faster boat.
Under 100 — Ultralight racer100–200 — Light cruiser/racer200–300 — Moderate cruiser300–400 — Heavy cruiserOver 400 — Very heavy
247.87
Comfort Ratio Ted Brewer's Comfort Ratio predicts how comfortable a boat will feel in offshore conditions. Higher values mean a steadier, more comfortable motion in a seaway.
Under 20 — Uncomfortably rough20–30 — Acceptable coastal30–40 — Good offshore comfortOver 40 — Very comfortable offshore
18.88
Capsize Screening Formula The USHS Capsize Screening Formula estimates offshore capsize risk. Lower is safer — values under 2.0 are considered acceptable for offshore sailing.
Under 2.0 — Safe for offshore2.0–2.2 — Borderline offshoreOver 2.2 — Coastal use recommended
2.01
Hull Speed Hull Speed is the theoretical maximum speed of a displacement hull, calculated from waterline length. Most cruising sailboats reach this speed in moderate conditions. 5.80 kn
Pounds/Inch Immersion Pounds per Inch Immersion (PPI) tells you how much weight is needed to sink the boat one inch. Useful for calculating how additional gear and stores affect waterline. 519.22 pounds/inch
How It Compares

vs. Chrysler 22 Fk, Cs 22, Etap 22, Hunter 22, Jaguar 22

This boat Similar boats
Dimensions
LOA
Westerly 21 ★
21.5 ft
Chrysler 22 Fk
21.6 ft
Cs 22
21.6 ft
Etap 22
21.7 ft
Hunter 22
21.5 ft
Jaguar 22
21.5 ft
LWL
Westerly 21 ★
18.8 ft
Chrysler 22 Fk
19.0 ft
Cs 22
17.5 ft
Etap 22
18.7 ft
Hunter 22
18.5 ft
Jaguar 22
19.3 ft
Beam
Westerly 21 ★
7.8 ft
Chrysler 22 Fk
7.8 ft
Cs 22
8.0 ft
Etap 22
7.9 ft
Hunter 22
8.0 ft
Jaguar 22
7.7 ft
Displacement
Westerly 21 ★
3 lbs
Chrysler 22 Fk
3 lbs
Cs 22
2 lbs
Etap 22
2 lbs
Hunter 22
2 lbs
Jaguar 22
2 lbs
Ballast
Westerly 21 ★
1 lbs
Chrysler 22 Fk
725 lbs
Cs 22
1 lbs
Etap 22
1 lbs
Hunter 22
1 lbs
Jaguar 22
550 lbs
Sail Area
Westerly 21 ★
210 sq ft
Chrysler 22 Fk
Cs 22
Etap 22
Hunter 22
213 sq ft
Jaguar 22
205 sq ft
Performance
PHRF Rating (lower = faster)
Westerly 21 ★
Chrysler 22 Fk
Cs 22
249 s/nm
Etap 22
Hunter 22
252 s/nm
Jaguar 22
SA / Displacement (higher = more powerful)
Westerly 21 ★
14.2
Chrysler 22 Fk
Cs 22
Etap 22
Hunter 22
17.8
Jaguar 22
19.2
Ballast / Disp (higher = stiffer)
Westerly 21 ★
45.8 %
Chrysler 22 Fk
Cs 22
50.0 %
Etap 22
44.0 %
Hunter 22
37.7 %
Jaguar 22
24.4 %
Comfort Ratio (higher = more comfortable offshore)
Westerly 21 ★
18.9
Chrysler 22 Fk
15.3
Cs 22
Etap 22
Hunter 22
13.1
Jaguar 22
11.5
Capsize Screening (lower = safer)
Westerly 21 ★
2.01
Chrysler 22 Fk
2.15
Cs 22
Etap 22
Hunter 22
2.32
Jaguar 22
2.34
Displacement / Length (lower = lighter)
Westerly 21 ★
247
Chrysler 22 Fk
Cs 22
183
Etap 22
188
Hunter 22
186
Jaguar 22
139
Hull Speed
Westerly 21 ★
5.8 kts
Chrysler 22 Fk
5.8 kts
Cs 22
Etap 22
Hunter 22
5.8 kts
Jaguar 22
5.9 kts
Speed Number (higher = faster)
Westerly 21 ★
Chrysler 22 Fk
2.7
Cs 22
Etap 22
Hunter 22
Jaguar 22
3.9
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