Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
96.29 ft
J ?
26.38 ft
P ?
87.79 ft
E ?
29.53 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 | 1,296.2 | 120.4 |
| 100% ForetriangleI × J ÷ 2 | 1,270.1 | 118.0 |
| 150% GenoaTypical light-air headsail | 1,905.1 | 177.0 |
| Storm Jib~50% of foretriangle, high-cut | 635.0 | 59.0 |
| Symmetric SpinnakerEstimated from I, J | 4,572.2 | 424.8 |
| Total Working Sail AreaMain + 100% foretriangle | 2,566.3 | 238.4 |
Foretriangle Diagram
Drawn to scale from published I, J, P, E measurements — Masthead Sloop · German Frers design
Performance Ratios
How the Swan 70 carries its sail relative to its displacement.
SA/D Ratio
24.6
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
36%
Typical cruising ballast — balanced stability underway.
Typical Sail Inventory
What Swan 70 owners usually carry and what's worth buying used vs. new.
Mainsail 1,296.2 ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 1,905.1 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~1,397 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 635.0 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~4,572 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 Swan 70 — Dacron, laminate, and cruising performance tiers.