The Irwin 325 is modestly canvassed and unhurried, with a steady, comfortable ride offshore.
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 26.0′, the Irwin 325 tops out around 6.8 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √26.0′ LWL = 6.8 kts
Performance Ratios
Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.
SA / Displacement
13.4
Modestly canvassed — a comfortable, unhurried cruiser.
Comfort Ratio
33.5
Good offshore comfort — steady enough for multi-day passages.
Capsize Screening
1.70
Below the 2.0 offshore threshold — acceptable for ocean passages.
Pounds/Inch Immersion
929lbs
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
33.5
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
1.70
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 325 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Cruiser/Racer 90–150
Cruiser 150–210
Heavy Cruiser 210–300
Ranger 32
162s/nm
Carter 33
180s/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° |
2.4 |
3.1 |
3.4 |
3.6 |
| Close Reach60° |
3.0 |
3.7 |
4.2 |
4.3 |
| Beam Reach90° |
3.6 |
4.6 |
5.1 |
5.3 |
| Broad Reach120–135° |
3.3 |
4.2 |
4.7 |
4.9 |
| Run150–180° |
2.7 |
3.4 |
3.8 |
3.9 |
These are simplified estimates based on hull speed (6.8 kts),
SA/D (13.4), 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 Irwin 325 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–8 kts
8–22 kts
22–30 kts
30+ kts
Ghosting
0–8 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
8–22 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
22–30 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
30+ 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 325.
|
Irwin 325 |
Carter 33 |
Islander 33 |
Pentland 32 Westerly |
Ranger 32 |
Renown 32 Westerly |
| Dimensions |
| LOA |
32.5 |
32.6 |
32.6 |
32.5 |
32.5 |
32.5 |
| LWL |
26.0 |
23.3 |
24.0 |
25.0 |
25.8 |
25.0 |
| Beam |
10.0 |
11.0 |
10.2 |
9.5 |
10.8 |
9.5 |
| Displacement |
13 |
7 |
10 |
10 |
9 |
10 |
| Ballast |
4 |
2 |
3 |
4 |
4 |
4 |
| Sail Area |
462 |
405 |
448 |
372 |
449 |
440 |
| Performance |
| PHRF |
— |
180 |
— |
— |
162 |
— |
| SA/Disp |
13.4 |
17.0 |
15.5 |
12.1 |
16.1 |
15.1 |
| Bal/Disp |
— |
— |
— |
40.6 |
— |
— |
| Comfort |
33.5 |
18.2 |
26.5 |
30.9 |
22.1 |
28.5 |
| Capsize |
1.70 |
2.25 |
1.89 |
1.71 |
2.05 |
1.76 |
| Hull Speed |
6.8 |
6.5 |
6.6 |
6.7 |
6.8 |
6.7 |