Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
47.90 ft
J ?
13.83 ft
P ?
52.16 ft
E ?
18.73 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 | 488.5 | 45.4 |
| 100% ForetriangleI × J ÷ 2 | 331.2 | 30.8 |
| 150% GenoaTypical light-air headsail | 496.8 | 46.2 |
| Storm Jib~50% of foretriangle, high-cut | 165.6 | 15.4 |
| Symmetric SpinnakerEstimated from I, J | 1,192.4 | 110.8 |
| Total Working Sail AreaMain + 100% foretriangle | 819.7 | 76.2 |
Foretriangle Diagram
Drawn to scale from published I, J, P, E measurements — Fractional Sloop · Alan Andrews design
Performance Ratios
How the Andrews 39 carries its sail relative to its displacement.
SA/D Ratio
24.2
Performance-oriented — carries a lot of sail for its weight.
Mast Height (above DWL)
— ft
Air draft not published — measure yours before any bridge transit.
Ballast Ratio
47%
Race-oriented ballast ratio — stiff and powerful.
Typical Sail Inventory
What Andrews 39 owners usually carry and what's worth buying used vs. new.
Mainsail 488.5 ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 496.8 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~364 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 165.6 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~1,192 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 Andrews 39 — Dacron, laminate, and cruising performance tiers.