THOMAS 35 Sail Configuration Guide

Overview

The THOMAS 35, designed by G&S and built by Tartan, is a performance-oriented racer-cruiser optimized for competitive fleet racing and fast coastal passages. It balances a generous sail plan with a deep 2.09m draft to deliver a stiff, weatherly experience for demanding sailors.

Rig Specifications & Performance Analysis

• Mainsail Configuration: A P/E ratio of 3.21 indicates a high-aspect rig, favoring upwind efficiency and lift.
• Foretriangle Design: The I/J ratio of 3.37 is well-suited for powerful genoas and versatile headsail configurations.
• Sail Area: 63m² of total upwind sail area provides a high power-to-displacement ratio.
• Performance: The rig is decidedly racing-oriented but remains stable enough for performance cruising.

Popular Sail Configurations

• Mainsail: Fleet data shows various configurations, often utilizing full battens to support the tall P/E ratio.
• Headsail: Setups typically range from 150% overlapping genoas for light-air performance to high-clew working jibs.

Key Characteristics

• High-aspect mainsail (3.21 P/E) generates superior lift and aerodynamic efficiency.
• Substantial foretriangle (3.37 I/J) allows for a diverse inventory of headsails.
• Deep 2.09m draft and 3.53m beam provide excellent stability and tracking.
• Responsive 63m² upwind sail plan ensures agility in light to moderate air.

Sailing Considerations

• Optimal performance is achieved in the 8–16 knot range; consider reefing when true wind exceeds 18 knots.
• Typical crew requirements for racing are 6–8 people, though the rig is manageable for experienced couples.
• Expect a close-winded, weatherly boat that rewards precise traveler and backstay adjustments.

Sailmaking Recommendations

For the THOMAS 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 in light air. For cruising or coastal racing, add a taffeta protective layer on both sides to enhance UV resistance and abrasion protection. Based on the 3.21 P/E ratio, a tri-radial fiber layout within the membrane works best to manage the high vertical loads of the tall rig. A typical inventory includes a high-roach mainsail, a 135% genoa, and an all-purpose reacher. With 63m² of sail area, plan to reef the 32m² mainsail around 17 knots to maintain a flat heel angle.

Conclusion

The THOMAS 35 is a refined G&S design that thrives with modern, high-modulus materials that can handle its high-aspect rig loads. Explore sail options for THOMAS 35 to unlock its full racing and cruising potential.