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Snapdragon 21
Designer: Thames Structural Plastics/Thames Marine  ·  Builder: Thames Marine  ·  First built: 1970
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About the Snapdragon 21

A compact and practical pocket cruiser, the Snapdragon 21 is part of the well-regarded Snapdragon family of British sailing boats that earned a loyal following throughout the latter half of the twentieth century. Built for accessibility and ease of use, this little vessel appeals to sailors looking for an affordable entry point into cruising without sacrificing the character and seaworthiness that the Snapdragon name became known for. Suited primarily to coastal and estuary sailing, the Snapdragon 21 is a capable daysailer that can handle the modest overnight passage in settled conditions. Its manageable size makes it ideal for short-handed sailing, and its British heritage means it was designed with the often unpredictable conditions of UK coastal waters in mind. The boat has historically attracted sailors who appreciate simplicity and reliability over complexity, and its strong secondhand presence on the market speaks to both its durability and the dedicated community that surrounds the Snapdragon brand. For those seeking a characterful and manageable coastal cruiser with genuine heritage behind it, the Snapdragon 21 remains a worthwhile option to consider.

Core Dimensions
LOA (Length Overall) 21.00 ft / 6.40 m
LWL (Waterline Length) 18.00 ft / 5.49 m
Beam 7.25 ft / 2.21 m
Max Draft 2.50 ft / 0.76 m
Displacement 2,200.00 lb / 998 kg
Ballast 950.00 lb / 431 kg
Sail Area (Reported) 188.00 ft² / 17.47 m²
Design & Construction
Hull Type Twin Keel
Rigging Type Masthead Sloop
Construction FG
Designer Thames Structural Plastics/Thames Marine
Builder Thames Marine
First Built 1970
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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
17.82
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
12.85
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
2.23
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. 5.69
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. 466.29
How It Compares

vs. Jouster 21 Westerly, Parker 21 Trailer Sailer 21, South Coast 21, Varianta, Venture 21

This boat Similar boats
Dimensions
LOA
Snapdragon 21 ★
21.0 ft
Jouster 21 Westerly
21.0 ft
Parker 21 Trailer Sailer 21
21.0 ft
South Coast 21
21.0 ft
Varianta
21.0 ft
Venture 21
21.0 ft
LWL
Snapdragon 21 ★
18.0 ft
Jouster 21 Westerly
18.3 ft
Parker 21 Trailer Sailer 21
18.8 ft
South Coast 21
14.3 ft
Varianta
17.7 ft
Venture 21
18.5 ft
Beam
Snapdragon 21 ★
7.3 ft
Jouster 21 Westerly
7.5 ft
Parker 21 Trailer Sailer 21
8.2 ft
South Coast 21
6.9 ft
Varianta
6.9 ft
Venture 21
6.8 ft
Displacement
Snapdragon 21 ★
2 lbs
Jouster 21 Westerly
2 lbs
Parker 21 Trailer Sailer 21
1 lbs
South Coast 21
2 lbs
Varianta
1 lbs
Venture 21
1 lbs
Ballast
Snapdragon 21 ★
950 lbs
Jouster 21 Westerly
950 lbs
Parker 21 Trailer Sailer 21
800 lbs
South Coast 21
625 lbs
Varianta
573 lbs
Venture 21
400 lbs
Sail Area
Snapdragon 21 ★
188 sq ft
Jouster 21 Westerly
210 sq ft
Parker 21 Trailer Sailer 21
220 sq ft
South Coast 21
206 sq ft
Varianta
Venture 21
Performance
PHRF Rating (lower = faster)
Snapdragon 21 ★
Jouster 21 Westerly
Parker 21 Trailer Sailer 21
South Coast 21
258 s/nm
Varianta
Venture 21
252 s/nm
SA / Displacement (higher = more powerful)
Snapdragon 21 ★
17.8
Jouster 21 Westerly
19.9
Parker 21 Trailer Sailer 21
22.6
South Coast 21
20.8
Varianta
Venture 21
Ballast / Disp (higher = stiffer)
Snapdragon 21 ★
Jouster 21 Westerly
Parker 21 Trailer Sailer 21
41.0 %
South Coast 21
31.3 %
Varianta
44.1 %
Venture 21
26.7 %
Comfort Ratio (higher = more comfortable offshore)
Snapdragon 21 ★
12.9
Jouster 21 Westerly
12.2
Parker 21 Trailer Sailer 21
9.5
South Coast 21
14.4
Varianta
Venture 21
Capsize Screening (lower = safer)
Snapdragon 21 ★
2.23
Jouster 21 Westerly
2.31
Parker 21 Trailer Sailer 21
2.62
South Coast 21
2.20
Varianta
Venture 21
Displacement / Length (lower = lighter)
Snapdragon 21 ★
Jouster 21 Westerly
Parker 21 Trailer Sailer 21
132
South Coast 21
303
Varianta
104
Venture 21
105
Hull Speed
Snapdragon 21 ★
5.7 kts
Jouster 21 Westerly
5.7 kts
Parker 21 Trailer Sailer 21
5.8 kts
South Coast 21
5.1 kts
Varianta
Venture 21
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