What is the Precision 21's sail area to displacement ratio?

The Precision 21 has a Sail Area to Displacement ratio (SA/D) of 21.41. Values between 14–18 are typical cruising sailboats; 18–22 is cruiser/racer; over 22 is performance racing.

What is the Precision 21's comfort ratio?

The Precision 21 has a Ted Brewer Comfort Ratio of 9.43. A ratio over 30 indicates good offshore comfort; over 40 is very comfortable offshore.

Is the Precision 21 safe for offshore sailing?

The Precision 21 has a Capsize Screening Formula value of 2.68. Values under 2.0 are considered acceptable for offshore sailing; under 1.8 is ideal.

What is the hull speed of the Precision 21?

The theoretical hull speed of the Precision 21 is 5.61 kn knots, calculated from its waterline length.

How much does a Precision 21 weigh?

The Precision 21 has a displacement of 1,875.00 lb and a length overall (LOA) of 20.75 ft.

How much does a used Precision 21 cost?

Based on 3 recent market listings, used Precision 21 sailboats typically sell for between $1,000 and $2,000, with a median asking price of $2,000. Price varies significantly based on year, condition, location, and included equipment.

Who designed the Precision 21?

The Precision 21 was designed by Jim Taylor, first built in 1986.

Precision 21 Performance — PHRF, SA/D, Hull Speed & Sailing Characteristics

The Precision 21 is well-powered with enough sail area to move in light air, 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.

5.6 kts

A displacement hull pushes a bow wave whose speed is limited by the waterline length. With a waterline of 17.5′, the Precision 21 tops out around 5.6 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.

1.34 × √17.5′ LWL = 5.6 kts

Performance Ratios

Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.

PHRF Rating

243s/nm

Heavy or slow cruiser — all about the journey, not the elapsed time.

SA / Displacement

21.4

Powerful cruiser/racer — quick in light air, reef early when it pipes up.

Ballast / Displacement

32.0%

Typical cruising ballast — balanced stability and motion underway.

Displacement / Length

156

Moderate — a good balance of speed and load-carrying ability.

Comfort Ratio

9.4

Quick, snappy motion — better for day sails and racing than long passages.

Capsize Screening

2.68

Above the 2.0 offshore threshold — best suited for coastal and protected waters.

Hull Speed

5.6kts

S# (Speed Number)

3.7

SA/Disp (Calculated)

20.3

Computed from measured I/J/P/E rather than reported sail area.

Pounds/Inch Immersion

516lbs

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

9.4

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

2.68

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 Precision 21 sits on the PHRF handicap spectrum — lower numbers mean faster boats.

Cruiser/Racer 90–150

Cruiser 150–210

Heavy Cruiser 210–300

Ultimate 20 144s/nm

Hunter 212 216s/nm

Precision 21 243s/nm Heavy or slow cruiser — all about the journey, not the elapsed time.

San Juan 21 2 252s/nm

Buccaneer 210 282s/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°	2.5	3.2	3.6	3.7
Close Reach60°	3.0	3.8	4.3	4.5
Beam Reach90°	3.7	4.7	5.3	5.7
Broad Reach120–135°	3.4	4.4	4.9	5.3
Run150–180°	2.8	3.5	3.9	4.1

These are simplified estimates based on hull speed (5.6 kts), SA/D (21.4), 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 Precision 21 — based on sail area, ballast, and displacement characteristics.

Ghost

Sweet Spot

Reef

Heavy

0–6 kts 6–18 kts 18–26 kts 26+ kts

Ghosting

0–6 kts

Light air, motor-sailing likely. Need patience and a light genoa.

Sweet Spot

6–18 kts

Comfortable under full sail. Best speed-to-comfort ratio.

Time to Reef

18–26 kts

Time to shorten sail. Reef the main, swap to a working jib.

Heavy Weather

26+ 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 Precision 21.

	Precision 21	Buccaneer 210	Hunter 212	Nimble 20	San Juan 21 2	Ultimate 20
Dimensions
LOA	20.8	20.8	21.0	20.9	20.5	20.8
LWL	17.5	18.3	18.0	19.8	17.0	18.0
Beam	8.3	8.0	9.2	7.8	7.0	8.0
Displacement	1	3	1	1	1	1
Ballast	600	900	140	400	400	450
Sail Area	203	191	202	207	—	243
Performance
PHRF	243	282	216	—	252	144
SA/Disp	21.4	14.7	21.9	22.0	—	36.6
Bal/Disp	32.0	30.0	7.8	21.6	32.0	—
Comfort	9.4	15.2	7.7	9.3	—	5.7
Capsize	2.68	2.22	3.02	2.53	—	3.10
Hull Speed	5.6	5.7	5.7	6.0	—	5.7