IN January 1991 The Mail reported how a new multi-million pound dock gate, which had dominated the Walney Channel for almost 12 months, was slowly sinking into the ground at Barrow’s Ramsden Dock.

Before starting a shift on the giant dock gates project, three teams of 16 divers had to climb a 20-metre high tower before they could go down into an excavation chamber below the structure.

Once in position, the divers worked a four-hour shift in an air pressure of 32 pounds per square inch.

After their shift, the divers then had to climb back up the tower and spend another four hours in a special decompression chamber.

Then they returned down the tower and went home.

The team of divers was playing a key role in building a massive 58,500 ton structure, made of concrete and steel, which would supersede the existing dock gate entrance, providing easier access for the giant Trident submarines under construction at the VSEL shipyard.  

Work started on the giant structure in February 1990 when the first concrete cutting edge was placed in position. Since then, the gate had grown to become the largest of its type in Europe.

The structure, called a caisson by construction workers, was 50 metres long, 49 metres wide and 24 metres high. Some 23,000 square metres of concrete had been poured into the complex array of steel reinforcing rods.

The whole structure would be sunk 22 metres into the ground by the divers, who washed away the sand and earth with high

The structure was slowly sinking into the ground at about 20 inches a day.

The ends of the gate had been given temporary bulkheads, which would be removed once the structure had been sunk into place.

Then, the new steel dock gates, which were lying afloat near Michaelson Road bridge, would be floated into position. Known as a vertical lift flap gate, it was 38 metres wide, 15 metres high and weighed 380 tons.

Once installed the entrance would be 37 metres wide and have a depth of water above the cill of almost 8 metres. This was about 7 metres wider and 3 metres deeper than the existing entrance.