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LWL (Length Water Line)

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LWL (Length Water Line) is the measurement of a boat's hull length exactly at the surface of the water, spanning from the forward point to the aft point where the water meets the hull. It is a critical metric for determining a boat's maximum theoretical speed, stability, and displacement efficiency.

Key Aspects of LWL:
Speed Calculation: LWL is used to determine a boat's hull speed. The theoretical max speed for displacement hulls is generally calculated in knots.

Performance: A longer LWL generally allows for higher average speeds.

Distinction from LOA: LWL is usually shorter than the Length Overall (LOA) due to overhangs (bow/stern extending beyond the water).

Variable Measurement: While designed (DWL) for a certain load, the actual LWL changes as a boat heels or carries more weight, typically increasing as the boat sails faster and its stern/bow sink deeper into the water.