Lanby buoy is a contraction of Large Automatic Navigation BuoY. Lanby buoys were first made in the USA by General Dynamics and adapted by Hawker Siddeley Dynamics for use in British waters in the early 1970s. The buoys were intended to replace lightships and were constructed as a circular hull with a central light to provide all-round visibility and a foghorn. They may also contain radio and radio beacons. The navigation buoy was to be monitored remotely from onshore and was designed to run for extended periods without repair. The running costs were estimated to be as little as 10% of those of a lightship. They are now obsolete.