Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
18.66 ft
J ?
7.28 ft
P ?
200.00 ft
E ?
146.64 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 | 14,664.0 | 1,362.3 |
| 100% ForetriangleI × J ÷ 2 | 67.9 | 6.3 |
| 150% GenoaTypical light-air headsail | 101.9 | 9.5 |
| Storm Jib~50% of foretriangle, high-cut | 34.0 | 3.2 |
| Symmetric SpinnakerEstimated from I, J | 244.5 | 22.7 |
| Total Working Sail AreaMain + 100% foretriangle | 14,731.9 | 1,368.6 |
Foretriangle Diagram
Drawn to scale from published I, J, P, E measurements — Fractional Sloop · Tom Thornycroft design
Performance Ratios
How the Swallow 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
59%
Race-oriented ballast ratio — stiff and powerful.
Typical Sail Inventory
What Swallow owners usually carry and what's worth buying used vs. new.
Mainsail 14,664.0 ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 101.9 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~75 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 34.0 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~245 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 Swallow — Dacron, laminate, and cruising performance tiers.