Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
18.51 ft
J ?
17.00 ft
P ?
— ft
E ?
— 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 | — | — |
| 100% ForetriangleI × J ÷ 2 | 157.3 | 14.6 |
| 150% GenoaTypical light-air headsail | 236.0 | 21.9 |
| Storm Jib~50% of foretriangle, high-cut | 78.7 | 7.3 |
| Symmetric SpinnakerEstimated from I, J | 566.4 | 52.6 |
| Total Working Sail AreaMain + 100% foretriangle | — | — |
Foretriangle Diagram
Scale diagram unavailable — I, J, P, and E measurements are not all published for the North American 40.
Performance Ratios
How the North American 40 carries its sail relative to its displacement.
SA/D Ratio
—
Sail Area / Displacement ratio not published.
Mast Height (above DWL)
— ft
Air draft not published — measure yours before any bridge transit.
Ballast Ratio
45%
Race-oriented ballast ratio — stiff and powerful.
Typical Sail Inventory
What North American 40 owners usually carry and what's worth buying used vs. new.
Mainsail — ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 236.0 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~173 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 78.7 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~566 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 North American 40 — Dacron, laminate, and cruising performance tiers.