The N500 Naviplane was a French hovercraft built by Société d'Etude et de Développement des Aéroglisseurs Marins (SEDAM) in Pauillac, Gironde for the cross English Channel route.

Intended to have a large passenger and crew capacity, as prototypes they were for a short while the largest hovercraft.

N500-02 - Ingénieur Jean Bertin[a] registered BL 341.931 at port of Boulogne Sur Mer was built for Seaspeed by SNCF in 1977.

It showed poor engine and hydraulic system reliability/ It had difficulty climbing the ramp to the Dover hoverpad during bad weather.

Obturation flaps system between the air cushion chamber and the skirts provided additional longitudinal and lateral control.