In sailing, trim refers to adjusting the angle and shape of the sails relative to the wind to maximize aerodynamic lift and optimize boat speed. Proper trim involves using sheets to set the sail angle and managing telltales to ensure smooth airflow. It also refers to the boat's balance on the water (fore-and-aft).

Key Aspects of Sail Trim:
Purpose: To generate optimal lift and minimize drag, allowing the boat to "slice" through the wind rather than just being pushed.

Technique: Trimmers adjust sheets to set the sail's angle of attack to the wind, aiming to keep telltales flowing smoothly.

Mainsail & Jib: The front sail (jib) and back sail (mainsail) are adjusted based on wind velocity, direction, and the boat's course.

Hull Trim: Refers to the boat's balance between the bow and stern (e.g., even keel, bow-down, or stern-down) to ensure efficient movement through the water.