The Rochdale Canal is in Northern England, between Manchester and Sowerby Bridge, part of the connected system of the canals of Great Britain. Its name refers to the town of Rochdale through which it passes. The Rochdale is a broad canal because its locks are wide enough to allow vessels of width. The canal runs for across the Pennines from the Bridgewater Canal at Castlefield Basin in Manchester to join the Calder and Hebble Navigation at Sowerby Bridge in West Yorkshire. As built, the canal had 92 locks. Whilst the traditional lock numbering has been retained on all restored locks, and on the relocated locks, the canal now has 91. Locks 3 and 4 have been replaced with a single deep lock, Tuel Lane Lock, which is numbered 3/4. The Rochdale Canal was conceived in 1776, when a group of 48 men from Rochdale raised £237 and commissioned James Brindley to conduct a survey of possible routes between Sowerby Bridge and Manchester. Brindley proposed a route similar to the one built, and another more expensive route via Bury. Further progress was not made until 1791, when John Rennie was asked to make a new survey in June, and two months later to make surveys for branches to Rochdale, Oldham and to a limeworks near Todmorden. Rennie at the time had no experience of building canals. The promoters, unsure as to whether to build a wide or a narrow canal, postponed the decision until an Act of Parliament had been obtained. The first attempt to obtain an act was made in 1792, but was opposed by mill owners, concerned about water supply. Rennie proposed using steam pumping engines, three in Yorkshire, eight in Lancashire, and one on the Burnley Branch, but the mill owners argued that 59 mills would be affected by the scheme, resulting in unemployment, and the bill was defeated. In September 1792, William Crosley and John Longbotham surveyed the area in an attempt to find locations for reservoirs which would not affect water supplies to the mills. A second bill was presented to Parliament, for a canal which would have a tunnel and 11 reservoirs.