What is the J/30's sail area to displacement ratio?

The J/30 has a Sail Area to Displacement ratio (SA/D) of 20.8. Values between 14–18 are typical cruising sailboats; 18–22 is cruiser/racer; over 22 is performance racing.

What is the J/30's comfort ratio?

The J/30 has a Ted Brewer Comfort Ratio of 23.56. A ratio over 30 indicates good offshore comfort; over 40 is very comfortable offshore.

Is the J/30 safe for offshore sailing?

The J/30 has a Capsize Screening Formula value of 1.73. Values under 2.0 are considered acceptable for offshore sailing; under 1.8 is ideal.

What is the hull speed of the J/30?

The theoretical hull speed of the J/30 is 7.62 knots, calculated from its waterline length.

How much does a J/30 weigh?

The J/30 has a displacement of 6,920 lb and a length overall (LOA) of 30.00 ft.

How much does a used J/30 cost?

Based on 5 recent market listings, used J/30 sailboats typically sell for between $14,900 and $15,500, with a median asking price of $14,900. Price varies significantly based on year, condition, location, and included equipment.

Who designed the J/30?

The J/30 was designed by Rod Johnstone, first built in 1979.

J/30 Performance — PHRF, SA/D, Hull Speed & Sailing Characteristics

Name: J/30
Brand: Rod Johnstone
Availability: InStock

The J/30 is well-powered with enough sail area to move in light air, with acceptable motion comfort for coastal passages, and respectable in club racing.

Hull Speed

The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.

7.6 kts

A displacement hull pushes a bow wave whose speed is limited by the waterline length. With a waterline of 25.0′, the J/30 tops out around 7.6 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.

1.34 × √25.0′ LWL = 6.7 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

144s/nm

Cruiser/racer — competitive in club racing, comfortable cruising.

SA / Displacement

20.8

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

Ballast / Displacement

39.3%

Stiff enough to carry a big genoa comfortably into moderate breeze.

Displacement / Length

109

Ultralight — responsive and fast, but carries less stores.

Comfort Ratio

23.6

Acceptable coastal comfort — fine for weekends, notice the chop offshore.

Capsize Screening

1.73

Below the 2.0 offshore threshold — acceptable for ocean passages.

Hull Speed

7.6kts

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

23.6

Acceptable coastal comfort — fine for weekends, notice the chop offshore.

Under 20 — Snappy, racing motion

20–30 — Acceptable coastal

30–40 — Good offshore comfort

Over 40 — Very comfortable offshore

Capsize Screening Formula

1.73

Below the 2.0 offshore threshold — acceptable for ocean passages.

Under 2.0 — Acceptable for offshore

Over 2.0 — Coastal / protected waters

PHRF Fleet Position

Where the J/30 sits on the PHRF handicap spectrum — lower numbers mean faster boats.

Racer 0–90

Cruiser/Racer 90–150

Cruiser 150–210

Moore 30 51s/nm

Capri 30 Catalina 111s/nm

Mirage 30 Sx 120s/nm

J/30 144s/nm Cruiser/racer — competitive in club racing, comfortable cruising.

Cs 30 150s/nm

Irwin 30 Citation 177s/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°	3.4	4.3	4.7	5.0
Close Reach60°	4.1	5.1	5.7	6.0
Beam Reach90°	5.0	6.3	7.0	7.6
Broad Reach120–135°	4.6	5.8	6.5	7.1
Run150–180°	3.7	4.7	5.2	5.4

These are simplified estimates based on hull speed (7.6 kts), SA/D (20.8), 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 J/30 — 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 J/30.

	J/30	Capri 30 Catalina	Cs 30	Irwin 30 Citation	Mirage 30 Sx	Moore 30
Dimensions
LOA	30.0	30.0	30.0	30.0	30.0	30.0
LWL	25.0	25.0	25.4	26.9	24.1	26.3
Beam	10.8	10.8	10.3	10.0	10.5	14.0
Displacement	6	8	8	10	5	2
Ballast	2	3	3	4	—	800
Sail Area	436	387	462	495	474	466
Performance
PHRF	144	111	150	177	120	51
SA/Disp	20.8	15.5	18.5	16.7	23.3	47.1
Bal/Disp	39.3	37.5	—	41.4	—	40.0
Comfort	23.6	12.0	20.8	26.9	15.4	3.4
Capsize	1.73	2.62	2.05	1.84	2.33	4.45
Hull Speed	7.6	6.6	6.8	7.0	6.6	6.9