Foot

Deutsch: Unterliek / Español: pujamen / Português: amura / Français: bordure / Italiano: inferitura

Foot in the maritime context refers to the bottom edge of a sail, which runs along the boom or the deck, depending on the type of sail and its rigging. The foot is a critical part of sail trim and performance, as its positioning and tension influence the overall shape and efficiency of the sail. Proper adjustment of the foot is essential for optimising the sail’s effectiveness in different wind conditions and sailing angles.

Description

The foot of a sail is the lower edge that typically extends between the tack (the forward lower corner) and the clew (the aft lower corner) of the sail. The way the foot is rigged and adjusted can vary based on the sail type:

Mainsail: The foot of the mainsail is usually attached to the boom, which runs parallel to the deck. Tension on the foot is adjusted using the outhaul, which pulls the clew toward the end of the boom, tightening the foot and flattening the sail to reduce drag in higher winds.
Jib or Genoa: The foot of these sails typically runs close to the deck or is slightly elevated. Adjusting the foot helps control the sail’s shape and the amount of draft (curvature), which affects the sail’s power and the boat's performance, particularly when sailing upwind.
Loose-Footed Sails: Some mainsails are not attached to the boom along the entire foot but are instead loose-footed, meaning they are only connected at the tack and clew. This configuration allows for more precise adjustments to the sail shape and flexibility in trimming.

The foot’s position and tension are adjusted using various controls, such as the outhaul, boom vang, or downhaul, which can change the draft and angle of the sail to suit different wind conditions and points of sail.

Application Areas

Sail Trimming: Proper adjustment of the foot is crucial for optimising sail shape, improving performance, and maintaining balance under sail. This involves adjusting the outhaul to control foot tension and sail curvature.
Racing: Competitive sailors pay close attention to foot tension to maximise speed and manoeuvrability. A properly trimmed foot helps in achieving optimal sail performance across varying wind strengths and directions.
Cruising: For cruising sailors, adjusting the foot of the sail ensures a balance between comfort and efficiency, making the sail easier to handle while still maintaining adequate speed.
Training and Instruction: Learning to manage the foot of the sail is a fundamental skill taught in sailing courses, as it directly impacts boat handling and sail trim.

Well-Known Examples

Laser Dinghy: A popular racing dinghy with a loose-footed mainsail, allowing sailors to adjust the foot tension easily for optimal performance in varying wind conditions.
Cruising Yachts: Most cruising yachts feature mainsails with the foot attached to a boom, allowing for straightforward trimming using the outhaul and other controls.
Classic Gaff-Rigged Vessels: These traditional sailing vessels have mainsails with a foot that may not be attached to a boom, requiring different techniques for adjusting sail shape and trim.

Treatment and Risks

Proper management of the sail’s foot is essential for maintaining optimal performance and avoiding potential issues:

Excessive Tension: Over-tightening the foot can flatten the sail too much, reducing power and affecting boat speed, particularly in light winds.
Insufficient Tension: If the foot is too loose, the sail can become overly full, leading to increased drag, heel, and reduced efficiency, especially in stronger winds.
Chafing and Wear: The foot of the sail can experience wear from rubbing against the boom or deck fittings. Regular inspection and maintenance, such as reinforcing weak spots or using protective coverings, can extend the sail's lifespan.
Improper Trim: Poorly adjusted foot tension can lead to inefficient sailing, making it harder to maintain course and speed, particularly when navigating upwind.

Similar Terms

Luff: The leading edge of the sail, running vertically from the tack to the head.
Leech: The trailing edge of the sail, extending from the head to the clew.
Clew: The aft lower corner of the sail where the foot and leech meet.
Tack: The forward lower corner of the sail where the foot and luff meet.

Summary

In the maritime context, the foot of a sail is the lower edge that plays a crucial role in the sail’s performance and handling. Proper adjustment of the foot is essential for optimising sail shape, improving speed, and ensuring balanced sailing. Whether in racing or cruising, managing the foot through controls like the outhaul is a key aspect of effective sail trimming, impacting the overall efficiency and performance of the vessel.

Glossary