The Royal Navy installed a number of defences in the harbour at Algiers, at the outset of World War 2. By early 1943 five indicator loop systems were installed as part of the controlled mining defences at the northern and southern entrances. These loops were connected to the control station on the shore by 4500 yds of tail cable, and were lain over a four mile front at the harbour entrances.  To supplement this, harbour defence asdics (HDAs) were also installed. At the same time loops had been approved for installation in the Mediterranean at the Alexandria, Dardanelles, Bosphorus, Smyrna, Malta and Haifa. This page is under construction. Please help.

If you worked there or have any feedback please email me:

Dr Richard Walding
Research Fellow - School of Science
Griffith University
Brisbane, Australia

LINKS TO MY RELATED PAGES: Indicator Loops around the World (Home Page) How an indicator loop works

Indicator Loops - an overview (YouTube, 70 minutes)


If you have any further details of Alexandria Bay Bay antisubmarine harbour defences in general (Indicator Loops and Harbour
Defence Asdic) that may help with this research project please email me at the address above.