Work out hull speed instantly with clear inputs, formula shown and shareable results.
Hull speed is 1.34 times the square root of waterline length in feet, the speed at which the wave the hull makes has a length equal to the hull itself. A displacement hull trying to exceed it must climb its own bow wave, so resistance rises very steeply — the reason long hulls are fast hulls.
Hull speed
V (kt) = 1.34 x sqrt(LWL in ft); Froude number = V / sqrt(g x LWL)
Marine results are planning estimates only. Verify against the vessel's approved stability booklet, loading manual, class society rules and applicable maritime regulations before loading or sailing.
Yes, if it has the power and the hull form to plane or semi-plane. Heavy displacement hulls effectively cannot.
It comes from deep-water wave speed: a wave whose length equals the waterline travels at 1.34 x sqrt(length in feet) knots.