Some 72,118 passengers were reported to have travelled through the ferry terminals during the week 15–21 April. That week saw the culmination of increased trade in Dublin Port, as the company's figures for the first quarter of 2010 would eventually reveal. March 2010 saw a 13.5% trade increase when compared with March 2009, and that month was declared by the company as the fourth consecutive month of trade increase since the economic downturn. The Port Company is responsible for pilotage services within Dublin Bay, and manages the three port lighthouses (but not those of Howth or Kish Bank). It also operates three diesel tugboats and two drydocks (located near Alexandra Quay) and provides divers for underwater hull inspections. It licences private companies to provide stevedoring services. Within the main port enclave, on the north side of the river, are a power generating station (gas-fired), several oil terminals and number of slightly-related businesses, such as car dealerships, and a Topaz fuelling station on Bond Road. Entered at the north side of the port, but lying in East Wall, is one end of the Dublin Port Tunnel. The medieval port of Dublin was located on the south bank of the Liffey near Christ Church Cathedral, a few miles upstream from its current location. In 1715, the Great South Wall was constructed to shelter the entrance to the port. Poolbeg Lighthouse at the end of the South Bull Wall was constructed in 1767. In 1800, a survey of Dublin Bay conducted by Captain William Bligh recommended the construction of the Bull Wall. After the completion of the wall in 1842, North Bull Island slowly formed as sand built up behind it. After James Gandon's Custom House was built further downstream in 1791, the port moved downstream to the north bank of the river estuary, where the International Financial Services Centre is currently located. The noise and dirt associated with the port traffic contributed to the decline of the formerly fashionable Mountjoy Square area, with many wealthy families moving to the Southside. The advent of containerisation in the second half of the 20th century resulted in the port gradually moving a mile further downstream to enable new wharves to be constructed. A 2018 review of a 'Draft Masterplan 2040' was published by the Dublin Port Company. By 2023, the current Terminal 3 will be converted into Berth 18 for Cruise ships. This new facility will replace the temporary check-in facility at Terminal 7 on Tolka Quay Road and eliminate the need to shuttle guests to Ocean Pier 33.