Glossary Term
LWL (Length at Waterline)
LWL stands for Length at Waterline. It is the length of the yacht where the hull meets the water, usually measured at a stated loading condition or at the design waterline. Unlike LOA, it does not describe the yacht’s total physical length. It describes the effective water-contact length of the hull.
Naval architects and engineering teams use LWL in performance calculations because it affects resistance, trim, and the speed-length relationship of the hull. As a general rule, a longer LWL supports more efficient passage through the water for a given hull form and displacement.
LWL is usually shorter than LOA, and it can change as loading, trim, or hull attitude changes. That is why two yachts with similar overall length may behave differently underway. In yacht design and performance discussions, LWL is often the more useful number.