The Arrol Gantry was a steel gantry surrounding two slipways in Harland and Wolff shipyard in Belfast, Northern Ireland. It was erected in 1908 by Sir William Arrol & Co. of Glasgow, whom had also built Tower Bridge and the Humber Bridge. The gantry was 6,000 tons heavy, 840 feet long, 270 feet wide and 228 feet high, taller than Westminster Abbey. It also featured four electric lifts, a central revolving crane and three rows of eleven towers. Each row was spaced by 121 feet and each tower by 80 feet.The gantry would be in use until it was demolished in the 1960s. The Arrol Gantry is best known for constructing the RMS Olympic, the infamous RMS Titanic and the HMHS Britannic.