Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
28.50 ft
J ?
9.50 ft
P ?
25.00 ft
E ?
10.25 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 | 128.1 | 11.9 |
| 100% ForetriangleI × J ÷ 2 | 135.4 | 12.6 |
| 150% GenoaTypical light-air headsail | 203.1 | 18.9 |
| Storm Jib~50% of foretriangle, high-cut | 67.7 | 6.3 |
| Symmetric SpinnakerEstimated from I, J | 487.4 | 45.3 |
| Total Working Sail AreaMain + 100% foretriangle | 263.5 | 24.5 |
Foretriangle Diagram
Drawn to scale from published I, J, P, E measurements — Masthead Sloop · Ted Irwin design
Performance Ratios
How the Irwin 23 carries its sail relative to its displacement.
SA/D Ratio
18.9
Powerful cruiser/racer — quick in light air, reef early in a blow.
Mast Height (above DWL)
31.5 ft
Clears the 65 ft ICW fixed-bridge standard with room to spare.
Ballast Ratio
47%
Race-oriented ballast ratio — stiff and powerful.
Typical Sail Inventory
What Irwin 23 owners usually carry and what's worth buying used vs. new.
Mainsail 128.1 ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 203.1 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~149 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 67.7 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~487 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 23 — Dacron, laminate, and cruising performance tiers.