J 35 Sail Configuration Guide

Overview

The J 35 is a legendary racer-cruiser designed by Johnstone and built by Bashford, engineered for high-performance offshore racing and fast coastal cruising. This design balances a competitive PHRF rating with a manageable platform for a dedicated crew.

Rig Specifications & Performance Analysis

• Mainsail Configuration: A P/E ratio of 2.61 indicates a moderate-to-high aspect rig, offering a balance of power and efficient twist control.
• Foretriangle Design: The I/J ratio of 3.49 defines a tall foretriangle, optimized for powerful overlapping genoas and high-aspect working jibs.
• Sail Area: With 57m² of total upwind sail area, the J 35 offers a high power-to-weight ratio.
• Performance: The rig geometry is optimized for weatherly performance and exceptional pointing ability in various sea states.

Popular Sail Configurations

• Mainsail: Standard configurations usually feature a full-batten or power-head design to maximize the 2.61 P/E ratio.
• Headsail: Setups range from 150% overlapping genoas for light air to non-overlapping blade jibs for heavy weather.

Key Characteristics

• P/E 2.61: Efficient mainsail plan providing excellent lift and reduced drag.
• I/J 3.49: Tall rig height relative to the base, supporting high-aspect headsails.
• 10.70m LOA: A versatile length that offers stability in offshore conditions while remaining nimble.
• Performance: Known for a stiff, stable ride and high responsiveness on the helm.

Sailing Considerations

• Optimal performance is achieved with active backstay tensioning to control headstay sag.
• Requires a crew of 6-8 for competitive racing to manage the large headsail loads.
• Maintains a balanced helm up to 20 knots of breeze before requiring the first reef.

Sailmaking Recommendations

For the J 35, we recommend SurgeX membrane sails as the optimal choice for most sailors. SurgeX uses continuous fiber construction where fibers are laid along load paths and embedded in a thin membrane, providing superior shape retention compared to traditional Dacron while being more affordable than premium laminates. The continuous fiber structure means less stretch over time, maintaining the designed sail shape for years.

For racing applications, specify a lightweight SurgeX configuration with minimal base weight to maximize performance. For cruising or bluewater sailing, add a taffeta protective layer on both sides to enhance UV resistance and abrasion protection. Based on the 2.61 P/E ratio, a membrane layout with load-path oriented fibers works best to handle the high leach tensions. A typical inventory includes a membrane mainsail and a versatile Code 2 or 3 jib. With 57m² of sail area, plan to reef the mainsail around 18-20 knots to maintain an upright, efficient plane.

Conclusion

The J 35 rig is a masterpiece of efficiency, offering a perfect blend of power and control. Explore sail options for the J 35 to maximize your boat's performance potential.