The Raid on Zeebrugge - 23rd April 1918

by Colin McKenzie

HMS Thetis, Intrepid and Iphigenia, awaiting preparation for the Raid (IWM)

THE PLAN OF ATTACK

An assault on Zeebrugge harbour had been discussed for some years, but until Keyes arrived the idea had been dismissed as too risky. Soon after his appointment Keyes resurrected and modified the plan and the Admiralty, keen for some action, gave him the go-ahead.

Keyes realised that trying to capture the port of Zeebrugge was far too ambitious, but a lightning attack with the aim of blocking the Bruges canal although dangerous was possible and would greatly reduce German submarine traffic in the Channel.  The plan was developed under great secrecy under the code name 'Operation ZO' standing for Zeebrugge/Ostende.

Three old coal-burning cruisers - Thetis, Intrepid and Iphigenia - were to be filled with concrete and sailed across the Channel with the minimum crew, to be scuttled across the entrance to the canal

A DIVERIONARY ATTACK

Because these ships would be sailing into the heavily defended Zeebrugge harbour within 100 yards of the German guns, a diversionary attack was to be launched to draw the enemy fire. Under cover of darkness and behind an immense smoke screen, a large raiding party would be landed on the Mole to engage the German troops stationed there and to destroy the heavy guns which covered the harbour and its approaches. This raiding party would be landed by a fourth redundant cruiser HMS Vindictive and withdrawn as soon as the blockships had manoeuvred into position and been scuttled.

German guns mounted on the end of the Mole (IWM)

The viaduct (after the attack) which connected the Mole to the mainland (IWM)

ATTACK THE VIADUCT

To prevent the Germans reinforcing their troops on the Mole during the attack, the viaduct which connected the Mole to the mainland was to be destroyed. An old submarine filled with explosives was to sail under the viaduct and be blown up.

If all went to plan the crews from the blockships and from the destroyed submarine would be rescued by fast motor boats and ferried back to destroyers waiting outside the harbour

... The Plan

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