The Irwin 42 is moderately powered for comfortable coastal cruising, with a steady, comfortable ride offshore, designed for cruising comfort rather than racing.
Hull Speed
The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.
A displacement hull pushes a bow wave whose speed is limited by the waterline length.
With a waterline of 35.1′, the Irwin 42 tops out around 7.9 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √35.1′ LWL = 7.9 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
168s/nm
Typical cruiser — designed for comfort and ease, not podium finishes.
SA / Displacement
15.3
Moderate sail power — a capable coastal cruiser, not overpowered.
Comfort Ratio
38.3
Good offshore comfort — steady enough for multi-day passages.
Capsize Screening
1.74
Below the 2.0 offshore threshold — acceptable for ocean passages.
Pounds/Inch Immersion
1lbs
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
38.3
Good offshore comfort — steady enough for multi-day passages.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
1.74
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 Irwin 42 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Racer 0–90
Cruiser/Racer 90–150
Cruiser 150–210
Tartan 42
114s/nm
Passport 42
132s/nm
Whitby 42
153s/nm
Irwin 42
168s/nm
Typical cruiser — designed for comfort and ease, not podium finishes.
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° |
3.0 |
3.8 |
4.2 |
4.4 |
| Close Reach60° |
3.6 |
4.6 |
5.1 |
5.4 |
| Beam Reach90° |
4.5 |
5.6 |
6.3 |
6.6 |
| Broad Reach120–135° |
4.1 |
5.2 |
5.8 |
6.1 |
| Run150–180° |
3.3 |
4.2 |
4.7 |
4.9 |
These are simplified estimates based on hull speed (7.9 kts),
SA/D (15.3), 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 Irwin 42 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–7 kts
7–20 kts
20–28 kts
28+ kts
Ghosting
0–7 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
7–20 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
20–28 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
28+ 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 Irwin 42.
|
Irwin 42 |
Lancer 42 |
Morgan 42 1 |
Passport 42 |
Tartan 42 |
Whitby 42 |
| Dimensions |
| LOA |
42.0 |
42.0 |
42.0 |
42.0 |
42.0 |
42.0 |
| LWL |
35.1 |
35.3 |
30.5 |
34.8 |
32.0 |
32.7 |
| Beam |
13.3 |
13.8 |
11.5 |
12.8 |
12.3 |
13.0 |
| Displacement |
29 |
21 |
19 |
25 |
22 |
23 |
| Ballast |
12 |
7 |
— |
9 |
9 |
8 |
| Sail Area |
899 |
906 |
789 |
764 |
758 |
875 |
| Performance |
| PHRF |
168 |
— |
— |
132 |
114 |
153 |
| SA/Disp |
15.3 |
19.1 |
17.8 |
14.2 |
15.5 |
17.1 |
| Bal/Disp |
— |
— |
— |
35.3 |
— |
— |
| Comfort |
38.3 |
26.5 |
33.4 |
35.6 |
34.5 |
33.6 |
| Capsize |
1.74 |
2.00 |
1.73 |
1.75 |
1.75 |
1.82 |
| Hull Speed |
7.9 |
8.0 |
7.4 |
7.9 |
7.6 |
7.7 |