MD 35 Sail Configuration Guide

Overview

The MD 35, designed by Mark Mills and built by M BOATS, is a high-performance daysailer and fleet racer. It balances modern racing geometry with a sleek, minimalist aesthetic targeted at competitive owners and refined coastal sailors.

Rig Specifications & Performance Analysis

• Mainsail Configuration: A P/E ratio of 2.64 indicates a tall, high-aspect rig designed for efficient lift and aerodynamic power.
• Foretriangle Design: An I/J ratio of 3.44 is optimized for high-aspect, non-overlapping jibs rather than large genoas.
• Sail Area: 47m² total upwind area provides a high power-to-displacement ratio for a 10.71m hull.
• Performance: The rig is oriented toward high-performance racing with exceptional close-hauled capability.

Popular Sail Configurations

• Mainsail: Configurations typically feature high-modulus materials to support the tall P dimension and maintain leach tension.
• Headsail: Most setups utilize high-aspect working jibs that maximize the 3.44 I/J ratio for easy tacking and efficiency.

Key Characteristics

• High 2.64 P/E ratio delivers superior upwind lift and acceleration in light to moderate air.
• Aggressive 3.44 I/J ratio allows for narrow-shroud, high-aspect headsails for tight pointing angles.
• Narrow 2.27m beam combined with a 2.21m draft ensures a stiff, weatherly platform.
• Low-drag hull dimensions favor a boat that is quick to plane and highly responsive to trim.

Sailing Considerations

• The MD 35 is a technical platform requiring precise sail trim to manage its tall aspect rig.
• Crew requirements are typically 4-6 members for racing, though it remains manageable for short-handed daysailing.
• Expect exceptional performance in light-to-medium air where the high-aspect rig shines.

Sailmaking Recommendations

For the MD 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 a carbon/technora fiber blend to maximize the 47m² upwind power. For cruising or daysailing, add a thin taffeta protective layer on both sides to enhance UV resistance and prevent abrasion during tacks. Based on the 2.64 P/E ratio, a fiber-mapped layout works best to handle the high vertical loads of the mainsail. A typical inventory includes a square-top or high-roach main, a light/medium J1, and an all-purpose J2. With 47m² of sail area on a narrow hull, plan to reef the main or depower the headsail around 16-18 knots of true wind.

Conclusion

The MD 35 is a specialized racing machine that rewards high-quality sail shapes and precise rig tuning. Explore sail options for MD 35 to unlock the full potential of this Mark Mills design.