Bridge House on Bridge Street was extended by George Quayle around 1809, deliberately built upward and outward to block the view of the sea from the Governor's residence at neighbouring Lorne House after a falling-out between the families; its oldest section dates from the early 18th century. Built of local limestone, the harbour-facing elevation was clad in weatherproof Manx slate because the porous limestone alone offered poor protection from the elements. From 1802 the house served as the base of Quayle's Bank, and today it is used as offices while its former boat house houses the Castletown Nautical Museum, whose centrepiece exhibit is George Quayle's schooner-yacht Peggy.