Rigging Dimensions
The four foretriangle measurements sailmakers need to quote a new suit.
I ?
49.83 ft
J ?
17.75 ft
P ?
42.83 ft
E ?
15.50 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 | 331.9 | 30.8 |
| 100% ForetriangleI × J ÷ 2 | 442.2 | 41.1 |
| 150% GenoaTypical light-air headsail | 663.4 | 61.6 |
| Storm Jib~50% of foretriangle, high-cut | 221.1 | 20.5 |
| Symmetric SpinnakerEstimated from I, J | 1,592.1 | 147.9 |
| Total Working Sail AreaMain + 100% foretriangle | 774.2 | 71.9 |
Foretriangle Diagram
Drawn to scale from published I, J, P, E measurements — Cutter · Bob Johnson design
Performance Ratios
How the Island Packet 40 carries its sail relative to its displacement.
SA/D Ratio
18.1
Powerful cruiser/racer — quick in light air, reef early in a blow.
Mast Height (above DWL)
53.7 ft
Clears the 65 ft ICW fixed-bridge standard with room to spare.
Ballast Ratio
44%
Stiff enough to carry a 150% genoa comfortably into moderate breeze.
Typical Sail Inventory
What Island Packet 40 owners usually carry and what's worth buying used vs. new.
Mainsail 331.9 ft²
Dacron cross-cut with 2 reef points is standard. Full-batten is a common upgrade.
Replace new
150% Genoa 663.4 ft²
The workhorse headsail. Most boats have one on a furler by now.
Replace new
110% Working Jib ~486 ft²
Good secondary sail for breezy days — used market is strong.
Buy used
Storm Jib 221.1 ft²
Bright orange recommended. Rarely used, hard to justify new.
Buy used
Asymmetric Spinnaker ~1,592 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 Island Packet 40 — Dacron, laminate, and cruising performance tiers.