A lightvessel, or lightship, is a ship that acts as a lighthouse in areas deemed unsuitable for proper lighthouse construction. Although some records exist of fire beacons being placed on ships in Roman times, the first modern lightship was invented by Robert Hamblin in 1734 and was located off the Nore sandbank at the mouth of the River Thames in London, England. Lightships have since been rendered obsolete by advancing lighthouse construction techniques, and by large automated navigation buoys (LANBY).