Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
20.83 ft
J ?
7.30 ft
P ?
185.00 ft
E ?
203.80 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 | 18,851.5 | 1,751.4 |
| 100% ForetriangleI × J ÷ 2 | 76.0 | 7.1 |
| 150% GenoaTypical light-air headsail | 114.0 | 10.6 |
| Storm Jib~50% of foretriangle, high-cut | 38.0 | 3.5 |
| Symmetric SpinnakerEstimated from I, J | 273.7 | 25.4 |
| Total Working Sail AreaMain + 100% foretriangle | 18,927.5 | 1,758.4 |
Foretriangle Diagram
Drawn to scale from published I, J, P, E measurements — Masthead Sloop · Ted Carpentier design
Performance Ratios
How the Aurora 21 carries its sail relative to its displacement.
SA/D Ratio
20.8
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
29%
Light ballast — tends to be tender; reef earlier.
Typical Sail Inventory
What Aurora 21 owners usually carry and what's worth buying used vs. new.
Mainsail 18,851.5 ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 114.0 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~84 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 38.0 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~274 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 Aurora 21 — Dacron, laminate, and cruising performance tiers.