Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
32.51 ft
J ?
10.30 ft
P ?
31.23 ft
E ?
11.08 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 | 173.0 | 16.1 |
| 100% ForetriangleI × J ÷ 2 | 167.4 | 15.6 |
| 150% GenoaTypical light-air headsail | 251.1 | 23.3 |
| Storm Jib~50% of foretriangle, high-cut | 83.7 | 7.8 |
| Symmetric SpinnakerEstimated from I, J | 602.7 | 56.0 |
| Total Working Sail AreaMain + 100% foretriangle | 340.4 | 31.6 |
Foretriangle Diagram
Drawn to scale from published I, J, P, E measurements — Fractional Sloop · Group Finot design
Performance Ratios
How the First 285 Beneteau carries its sail relative to its displacement.
SA/D Ratio
16.3
Moderate — comfortable coastal cruiser, not overcanvassed.
Mast Height (above DWL)
— ft
Air draft not published — measure yours before any bridge transit.
Ballast Ratio
34%
Typical cruising ballast — balanced stability underway.
Typical Sail Inventory
What First 285 Beneteau owners usually carry and what's worth buying used vs. new.
Mainsail 173.0 ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 251.1 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~184 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 83.7 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~603 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 First 285 Beneteau — Dacron, laminate, and cruising performance tiers.