Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
70.00 ft
J ?
23.50 ft
P ?
62.85 ft
E ?
17.00 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 | 534.2 | 49.6 |
| 100% ForetriangleI × J ÷ 2 | 822.5 | 76.4 |
| 150% GenoaTypical light-air headsail | 1,233.8 | 114.6 |
| Storm Jib~50% of foretriangle, high-cut | 411.3 | 38.2 |
| Symmetric SpinnakerEstimated from I, J | 2,961.0 | 275.1 |
| Total Working Sail AreaMain + 100% foretriangle | 1,356.7 | 126.0 |
Foretriangle Diagram
Drawn to scale from published I, J, P, E measurements — Masthead Ketch · Sparkman & Stephens design
Performance Ratios
How the Swan 57 Ss Ketch carries its sail relative to its displacement.
SA/D Ratio
18.8
Powerful cruiser/racer — quick in light air, reef early in a blow.
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 Swan 57 Ss Ketch owners usually carry and what's worth buying used vs. new.
Mainsail 534.2 ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 1,233.8 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~905 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 411.3 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~2,961 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 57 Ss Ketch — Dacron, laminate, and cruising performance tiers.