THOMAS 35 Sail Configuration Guide

Overview

Designed by Graham & Schlageter and built by Tartan, the THOMAS 35 is a high-performance cruiser-racer known for its competitive edge. It targets sailors seeking a balance between offshore racing capability and functional coastal cruising comfort.

Rig Specifications & Performance Analysis

• Mainsail Configuration: A P/E ratio of 2.68 indicates a moderate-high aspect rig, offering efficient lift and versatile power delivery across wind ranges.
• Foretriangle Design: The I/J ratio of 3.35 is relatively high, optimized for powerful overlapping genoas and efficient headsail aerodynamics.
• Sail Area: 61m² total upwind area provides a high power-to-displacement ratio for a 10.78m hull.
• Performance: The deep 2.08m draft and refined rig geometry ensure a stiff, weatherly boat capable of excellent upwind pointing angles.

Popular Sail Configurations

• Mainsail: Typically features a full-batten configuration for cruising longevity or a loose-footed design for precise racing shape control.
• Headsail: Most owners utilize a 135-150% genoa for light air, transitioning to a high-clew 100% jib for heavy air performance.

Key Characteristics

• P/E ratio of 2.68: Provides a moderate-high aspect mainsail that is easy to depower in gusts.
• I/J ratio of 3.35: Supports large, powerful headsails essential for performance in light-to-moderate conditions.
• 2.08m Draft: Ensures high stability and reduced leeway when sailing close-hauled.
• Graham & Schlageter Pedigree: A design focused on minimizing drag while maximizing sail efficiency.

Sailing Considerations

• Requires active trimming to manage the generous 61m² upwind sail area in building breezes.
• Recommended for a crew of 6-8 for racing, though it remains manageable for an experienced couple while cruising.
• Performance is characterized by rapid acceleration and a responsive helm.

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 specific 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 significantly less stretch over time, maintaining the designed sail shape for years of active use.

For racing applications, specify a lightweight SurgeX configuration with minimal base weight to maximize performance in light air. For cruising or performance cruising, add a taffeta protective layer on both sides to enhance UV resistance and abrasion protection against the rig. Based on the 2.68 P/E ratio, a fiber-aligned layout works best to handle the vertical loads of the high-aspect mainsail. A typical inventory includes a SurgeX mainsail, a 140% reacher, and a dedicated heavy-weather jib. With 61m² of sail area, plan to take the first reef around 18-20 knots to maintain an upright, efficient plane.

Conclusion

The THOMAS 35 is a versatile performance platform that rewards high-quality sail shapes and modern materials. Explore SurgeX membrane sail options for your THOMAS 35 to maximize your boat's potential.