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Sonic 23
Designer: Joseph D'alessio  ·  Builder: Sonic Sailboats Ltd. (Can)  ·  First built: 1981
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About the Sonic 23

Designed by Joseph D'Alessio and built by Sonic Sailboats Ltd. in Canada starting in 1981, this compact 23-footer represents solid value in the trailerable cruiser market. With a length overall of 23 feet and waterline length of 20 feet, the Sonic 23 offers respectable interior volume while remaining manageable for single-handed sailing or small crew adventures. The boat's fin keel configuration with transom-hung rudder provides responsive handling characteristics, while the substantial ballast-to-displacement ratio of 44% ensures good stability and stiff sailing performance. Her masthead sloop rig carries 242 square feet of sail area, delivering adequate power for coastal cruising and weekend adventures without being overwhelming in fresh conditions. Built with fiberglass construction, the Sonic 23 demonstrates typical early-1980s build quality with straightforward systems that appeal to budget-conscious sailors. The boat's hull speed of nearly 6 knots and moderate sail area-to-displacement ratio make her well-suited for relaxed coastal cruising rather than aggressive racing. Her comfort ratio suggests she's designed more for protected waters and day sailing, though capable crews can certainly venture into open water conditions. The Sonic 23 remains an attractive option for sailors seeking an affordable entry into keelboat sailing or those wanting a simple, no-nonsense coastal cruiser.

Core Dimensions
LOA (Length Overall) 23.00 ft / 7.01 m
LWL (Waterline Length) 20.00 ft / 6.10 m
Beam 7.58 ft / 2.31 m
Max Draft 3.75 ft / 1.14 m
Displacement 3,400.00 lb / 1,542 kg
Ballast 1,500.00 lb / 680 kg
Ballast Type Iron
Sail Area (Reported) 242.00 ft² / 22.48 m²
Design & Construction
Hull Type Fin w/transom hung rudder
Rigging Type Masthead Sloop
Construction FG
Designer Joseph D'Alessio
Builder Sonic Sailboats Ltd. (CAN)
First Built 1981
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Performance Ratios
PHRF Rating PHRF (Performance Handicap Racing Fleet) is a national racing handicap measured in seconds per nautical mile. Lower values indicate faster boats. Ratings are sourced from US Sailing's national database (median across 60+ regional fleets).
Under 0 — Ultralight racer0–90 — Performance racer90–150 — Cruiser/racer150–210 — Typical cruiserOver 210 — Heavy/slow cruiser
 227
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
 17.17
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
 44.12
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
 189.73
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
 16.92
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
 2.02
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. 5.99 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
 2.85
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. 541.68 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. 17.17
Rig Dimensions
I (Foretriangle Height) 27.00 ft / 8.23 m
J (Foretriangle Base) 10.00 ft / 3.05 m
P (Mainsail Luff) 23.00 ft / 7.01 m
E (Mainsail Foot) 9.30 ft / 2.83 m
SA Fore 135.00 ft² / 12.54 m²
SA Main 106.95 ft² / 9.94 m²
SA Total (100%) 241.95 ft² / 22.48 m²
Est. Forestay Length 28.79 ft / 8.78 m
Mast Height (DWL) 30.67 ft / 9.35 m
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