Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
42.00 ft
J ?
17.60 ft
P ?
35.60 ft
E ?
14.60 ft
Sail Area Breakdown
Calculated from rigging dimensions. Use these as your starting point when ordering a new suit.
| Sail | Area (ft²) | Area (m²) |
|---|---|---|
| MainsailP × E ÷ 2 | 259.9 | 24.1 |
| 100% ForetriangleI × J ÷ 2 | 369.6 | 34.3 |
| 150% GenoaTypical light-air headsail | 554.4 | 51.5 |
| Storm Jib~50% of foretriangle, high-cut | 184.8 | 17.2 |
| Symmetric SpinnakerEstimated from I, J | 1,330.6 | 123.6 |
| Total Working Sail AreaMain + 100% foretriangle | 629.5 | 58.5 |
Foretriangle Diagram
Drawn to scale from published I, J, P, E measurements — Cutter · Ted Irwin design
Performance Ratios
How the Irwin 37 3 carries its sail relative to its displacement.
SA/D Ratio
13.7
Heavy and modestly canvassed — a comfortable cruiser, not fast.
Mast Height (above DWL)
46.0 ft
Clears the 65 ft ICW fixed-bridge standard with room to spare.
Ballast Ratio
39%
Stiff enough to carry a 150% genoa comfortably into moderate breeze.
Typical Sail Inventory
What Irwin 37 3 owners usually carry and what's worth buying used vs. new.
Mainsail 259.9 ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 554.4 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~407 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 184.8 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~1,331 ft²
Popular downwind upgrade — easier than symmetric for shorthanded sailing.
Optional
Replacement Cost Estimator
Get a rough price range for a new mainsail and genoa for the Irwin 37 3 — Dacron, laminate, and cruising performance tiers.