Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
34.45 ft
J ?
10.50 ft
P ?
38.71 ft
E ?
13.78 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 | 266.7 | 24.8 |
| 100% ForetriangleI × J ÷ 2 | 180.9 | 16.8 |
| 150% GenoaTypical light-air headsail | 271.3 | 25.2 |
| Storm Jib~50% of foretriangle, high-cut | 90.4 | 8.4 |
| Symmetric SpinnakerEstimated from I, J | 651.1 | 60.5 |
| Total Working Sail AreaMain + 100% foretriangle | 447.6 | 41.6 |
Foretriangle Diagram
Drawn to scale from published I, J, P, E measurements — Fractional Sloop · Matti Pulli design
Performance Ratios
How the Mp 31 carries its sail relative to its displacement.
SA/D Ratio
21.6
Powerful cruiser/racer — quick in light air, reef early in a blow.
Mast Height (above DWL)
45.9 ft
Clears the 65 ft ICW fixed-bridge standard with room to spare.
Ballast Ratio
—
Ballast ratio not published.
Typical Sail Inventory
What Mp 31 owners usually carry and what's worth buying used vs. new.
Mainsail 266.7 ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 271.3 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~199 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 90.4 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~651 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 Mp 31 — Dacron, laminate, and cruising performance tiers.