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Boomerang 20
Designer: Eric Maizey  ·  Builder: Maison Marine (Aus)/Peninsula Yachts (Aus)  ·  First built: 1968
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About the Boomerang 20

Designed by Eric Maizey and launched in 1968, this compact Australian sailboat carved out a reputation as a versatile coastal cruiser during the height of the small boat sailing boom. Built by Maison Marine and later Peninsula Yachts, the Boomerang 20 represents practical yacht design focused on ease of handling and shallow-water capability. The boat's most distinctive feature is its swing keel configuration, allowing the 4.16-foot draft to be reduced significantly for beaching, shallow anchorages, or trailer launching. This flexibility makes it particularly appealing for coastal exploration and gunkholing in protected waters. The fractional sloop rig with 183 square feet of sail area provides adequate power while remaining manageable for small crews. At 1,830 pounds with 531 pounds of ballast, the fiberglass construction strikes a reasonable balance between stability and trailability. The comfort ratio of 10.49 suggests a relatively stiff motion in choppy conditions, while the capsize screening value of 2.36 indicates this is clearly a boat intended for protected waters rather than offshore passages. With a hull speed of 5.81 knots and moderate sail area-to-displacement ratio, performance is respectable for weekend cruising and casual sailing. The Boomerang 20 appeals to sailors seeking an affordable entry into cruising with the convenience of shallow-draft versatility.

Core Dimensions
LOA (Length Overall) 20.64 ft / 6.29 m
LWL (Waterline Length) 18.80 ft / 5.73 m
Beam 7.22 ft / 2.20 m
Max Draft 4.16 ft / 1.27 m
Min Draft 1.00 ft / 0.30 m
Displacement 1,830.00 lb / 830 kg
Ballast 531.00 lb / 241 kg
Sail Area (Reported) 183.00 ft² / 17.00 m²
Design & Construction
Hull Type Swing Keel
Rigging Type Fractional Sloop
Construction FG
Designer Eric Maizey
Builder Maison Marine (AUS)/Peninsula Yachts (AUS)
First Built 1968
Related Sailboats Cal 21 · San Juan 21 · Precision 21 · Buccaneer 210 · Islander 21
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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
19.61
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
29.02
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
122.95
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
10.49
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
2.36
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. 5.81 kn
S# (Speed Number) The Speed Number (S#) is a quick performance index. Higher values indicate a faster, more powerful design relative to its size.
Under 3.0 — Slow cruiser3.0–5.0 — Average cruiser5.0–7.0 — Performance cruiserOver 7.0 — Racer
4.15
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. 485.00 pounds/inch
SA/Displacement (Calc) Calculated Sail Area to Displacement ratio using actual measured sail dimensions rather than reported values. More precise than the reported SA/Disp figure. 19.23
Rig Dimensions
I (Foretriangle Height) 23.98 ft / 7.31 m
J (Foretriangle Base) 8.26 ft / 2.52 m
P (Mainsail Luff) 20.75 ft / 6.32 m
E (Mainsail Foot) 7.75 ft / 2.36 m
SA Fore 99.04 ft² / 9.20 m²
SA Main 80.41 ft² / 7.47 m²
SA Total (100%) 179.45 ft² / 16.67 m²
Est. Forestay Length 25.36 ft / 7.73 m
How It Compares

vs. Buccaneer 210, Cal 21, Islander 21, Precision 21, San Juan 21

This boat Similar boats
Dimensions
LOA
Boomerang 20 ★
20.6 ft
Buccaneer 210
20.8 ft
Cal 21
20.5 ft
Islander 21
20.8 ft
Precision 21
20.8 ft
San Juan 21
20.5 ft
LWL
Boomerang 20 ★
18.8 ft
Buccaneer 210
18.3 ft
Cal 21
16.7 ft
Islander 21
18.0 ft
Precision 21
17.5 ft
San Juan 21
17.0 ft
Beam
Boomerang 20 ★
7.2 ft
Buccaneer 210
8.0 ft
Cal 21
6.7 ft
Islander 21
7.8 ft
Precision 21
8.3 ft
San Juan 21
7.0 ft
Displacement
Boomerang 20 ★
1 lbs
Buccaneer 210
3 lbs
Cal 21
1 lbs
Islander 21
1 lbs
Precision 21
1 lbs
San Juan 21
1 lbs
Ballast
Boomerang 20 ★
531 lbs
Buccaneer 210
900 lbs
Cal 21
360 lbs
Islander 21
1 lbs
Precision 21
600 lbs
San Juan 21
400 lbs
Sail Area
Boomerang 20 ★
183 sq ft
Buccaneer 210
191 sq ft
Cal 21
196 sq ft
Islander 21
215 sq ft
Precision 21
203 sq ft
San Juan 21
190 sq ft
Performance
PHRF Rating (lower = faster)
Boomerang 20 ★
Buccaneer 210
282 s/nm
Cal 21
261 s/nm
Islander 21
279 s/nm
Precision 21
243 s/nm
San Juan 21
258 s/nm
SA / Displacement (higher = more powerful)
Boomerang 20 ★
19.6
Buccaneer 210
14.7
Cal 21
29.5
Islander 21
22.1
Precision 21
21.4
San Juan 21
26.3
Ballast / Disp (higher = stiffer)
Boomerang 20 ★
29.0 %
Buccaneer 210
30.0 %
Cal 21
32.7 %
Islander 21
51.3 %
Precision 21
32.0 %
San Juan 21
Comfort Ratio (higher = more comfortable offshore)
Boomerang 20 ★
10.5
Buccaneer 210
15.2
Cal 21
7.6
Islander 21
10.3
Precision 21
9.4
San Juan 21
8.0
Capsize Screening (lower = safer)
Boomerang 20 ★
2.36
Buccaneer 210
2.22
Cal 21
2.59
Islander 21
2.51
Precision 21
2.68
San Juan 21
2.60
Displacement / Length (lower = lighter)
Boomerang 20 ★
122
Buccaneer 210
217
Cal 21
106
Islander 21
149
Precision 21
156
San Juan 21
Hull Speed
Boomerang 20 ★
5.8 kts
Buccaneer 210
5.7 kts
Cal 21
5.5 kts
Islander 21
5.7 kts
Precision 21
5.6 kts
San Juan 21
5.5 kts
Speed Number (higher = faster)
Boomerang 20 ★
4.2
Buccaneer 210
2.3
Cal 21
6.0
Islander 21
4.1
Precision 21
3.7
San Juan 21
5.4
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