Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
18.73 ft
J ?
12.50 ft
P ?
— ft
E ?
— 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 | — | — |
| 100% ForetriangleI × J ÷ 2 | 117.1 | 10.9 |
| 150% GenoaTypical light-air headsail | 175.6 | 16.3 |
| Storm Jib~50% of foretriangle, high-cut | 58.5 | 5.4 |
| Symmetric SpinnakerEstimated from I, J | 421.4 | 39.2 |
| Total Working Sail AreaMain + 100% foretriangle | — | — |
Foretriangle Diagram
Scale diagram unavailable — I, J, P, and E measurements are not all published for the Tartan 31 Piper.
Performance Ratios
How the Tartan 31 Piper 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
40%
Stiff enough to carry a 150% genoa comfortably into moderate breeze.
Typical Sail Inventory
What Tartan 31 Piper owners usually carry and what's worth buying used vs. new.
Mainsail — ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 175.6 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~129 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 58.5 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~421 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 Tartan 31 Piper — Dacron, laminate, and cruising performance tiers.