Like all the other locks on the canal Irlam locks rest on a foundation of solid sandstone rock with concrete lying on top. Below the water level the lock walls are built of concrete but are lined above the water with brick and blue facing brick. All fender courses, copings and corners of the gate chambers are of dressed cornish granite.
The lock gates built of greenheart wood, a wood so heavy that it sinks in water and which is so indestructible that it is considered superior to steel. The various sections of the gates are tied together with iron plates and bolts.
All the lock gates are constructed to move on rollers for ease of opening and are operated by hydraulic rams attached to chains, the rams and associated cylinders themselves being fixed into chambers within the lock walls.
The water enters the locks by means of sluices positioned in tunnels within the walls and there is a sluice between each of the locks which can be brought into use if there is a need to save water. The inlet sluices in each lock have 4 openings designed to spread the water flow and minimise currents within the lock.
The two locks here are 600 x 65ft and 350 x 45 ft in size and provide a lift of 16 feet and with the larger lock being situated on the Irlam side of the canal.
Alongside the locks, on the Flixton side, are 5 sluices each of which is built to the same design as those at the other locks along the canal.
The locks here were the scene of a major incident during March 1969 when the 12,000 ton Manchester Liners vessel Manchester Courage, outward bound for Montreal, rammed and burst open the lower lock gates of the large lock, causing the water level to fall substantially between Irlam and the locks at Barton. The damage was so great that all ships further up the canal were trapped for a period of five weeks while the gates were replaced and the water lever raised to it's normal level.
The MV Arklow Valley seen here entering the large lock, inbound to the Crerestar Wharf with a cargo of maize.
Irlam viaduct can be seen in the distance and the swing footbridge can be seen in its open position at the far left
of the photograph.
An unusual visitor to the canal, the patrol vessel HMS Biter is seen here entering the large
lock on her way towards the estuary following a visit to Manchester.