IC 37 Sail Configuration Guide

Overview

The IC 37 is a high-performance one-design racer developed by Melges and designed by Mills, specifically created for competitive grand prix and club racing. The design philosophy focuses on strict one-design uniformity and exhilarating performance for amateur crews.

Rig Specifications & Performance Analysis

• Mainsail Configuration: A P/E ratio of 2.96 indicates a modern, high-aspect ratio rig designed for maximum aerodynamic efficiency.
• Foretriangle Design: The I/J ratio of 3.43 is optimized for non-overlapping high-aspect working jibs rather than large genoas.
• Sail Area: 70m² of total upwind sail area provides a high power-to-weight ratio for its 11.30m length.
• Performance: The configuration is purely racing-oriented, prioritizing speed and close-winded performance over cruising comfort.

Popular Sail Configurations

• Mainsail: High-roach or square-top configurations are common to maximize the tall P/E geometry.
• Headsail: Primarily vertically battened, high-aspect jibs that utilize the full foretriangle height.

Key Characteristics

• High-Aspect Rig: The 2.96 P/E ratio reduces induced drag and improves upwind pointing angles.
• Efficient Foretriangle: A 3.43 I/J ratio allows for easy tacking and precise headsail sheeting.
• Powerful Platform: The 3.65m beam provides the necessary form stability to carry 70m² of sail.
• Responsive Handling: Modern hull and rig dimensions create a boat that is both stiff and weatherly.

Sailing Considerations

• Optimized for a wide range of conditions, performing best in 8-20 knots of true wind.
• Requires a coordinated crew of 8-10 to manage weight and high-load sail trimming.
• High responsiveness to backstay and outhaul adjustments due to the carbon rig design.

Sailmaking Recommendations

For the IC 37, 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 and reduce pitching. For delivery or training, add a thin taffeta protective layer on both sides to enhance UV resistance and abrasion protection. Based on the 2.96 P/E ratio, a load-path membrane layout works best to handle the high vertical loads of the mainsail luff. A typical inventory includes a high-aspect mainsail, a J1 light/medium jib, and a J2 heavy jib. With 70m² of sail area, plan to reef the mainsail around 22 knots to maintain a flat, manageable profile.

Conclusion

The IC 37 is a masterclass in modern racing design, utilizing a high-aspect rig to deliver exceptional speed. Explore professional SurgeX membrane sail options for your IC 37 to ensure competitive performance.