East Indiamen were the largest merchant ships regularly built during the late 18th and early 19th centuries, generally measuring between 1100 and 1400 tons burthen (bm). Two of the largest were the "Earl of Mansfield" and "Lascelles" being built at Deptford in 1795. The Royal Navy purchased both, converted them to 56-gun fourth rates, and renamed them "Weymouth" and "Madras" respectively. They measured 1426 tons (bm) on dimensions of approximately 175 feet overall length of hull, 144 feet keel, 43 feet beam, 17 feet draft.