Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
38.00 ft
J ?
11.17 ft
P ?
31.75 ft
E ?
10.00 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 | 158.8 | 14.7 |
| 100% ForetriangleI × J ÷ 2 | 212.2 | 19.7 |
| 150% GenoaTypical light-air headsail | 318.3 | 29.6 |
| Storm Jib~50% of foretriangle, high-cut | 106.1 | 9.9 |
| Symmetric SpinnakerEstimated from I, J | 764.0 | 71.0 |
| Total Working Sail AreaMain + 100% foretriangle | 371.0 | 34.5 |
Foretriangle Diagram
Drawn to scale from published I, J, P, E measurements — Masthead Sloop · Laurent Giles design
Performance Ratios
How the Longbow 31 Westerly carries its sail relative to its displacement.
SA/D Ratio
13.4
Heavy and modestly canvassed — a comfortable cruiser, not fast.
Mast Height (above DWL)
— ft
Air draft not published — measure yours before any bridge transit.
Ballast Ratio
—
Ballast ratio not published.
Typical Sail Inventory
What Longbow 31 Westerly owners usually carry and what's worth buying used vs. new.
Mainsail 158.8 ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 318.3 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~233 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 106.1 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~764 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 Longbow 31 Westerly — Dacron, laminate, and cruising performance tiers.