INFORMATION:

The two main piers were called 'Stores Piers & the smaller the 'Barge Pier'. The outer line of pier'. heads below were called 'Spuds'. Each items name was a code word to keep them a secret.
Obsolete merchant ships 'Gooseberries' were first sunk in a line to create an outer defence against the incoming waves & weather. Then added to them were concrete caissons 'Phoenixes' were sunk completing the outer harbour wall.