Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
33.00 ft
J ?
12.16 ft
P ?
30.00 ft
E ?
13.50 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 | 202.5 | 18.8 |
| 100% ForetriangleI × J ÷ 2 | 200.6 | 18.6 |
| 150% GenoaTypical light-air headsail | 301.0 | 28.0 |
| Storm Jib~50% of foretriangle, high-cut | 100.3 | 9.3 |
| Symmetric SpinnakerEstimated from I, J | 722.3 | 67.1 |
| Total Working Sail AreaMain + 100% foretriangle | 403.1 | 37.5 |
Foretriangle Diagram
Drawn to scale from published I, J, P, E measurements — Masthead Sloop · Herreshoff/Cheoy Lee Shipyard design
Performance Ratios
How the Offshore 31 Cheoy Lee carries its sail relative to its displacement.
SA/D Ratio
13.3
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
36%
Typical cruising ballast — balanced stability underway.
Typical Sail Inventory
What Offshore 31 Cheoy Lee owners usually carry and what's worth buying used vs. new.
Mainsail 202.5 ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 301.0 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~221 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 100.3 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~722 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 Offshore 31 Cheoy Lee — Dacron, laminate, and cruising performance tiers.