Roger Keyes’ Strategy on the Zeebrugge Raid: Blockships and a Smokescreen

In World War I, Captain Roger Keyes was chosen to storm the Bruges canal in Belgium that provided exits to the open seas via Ostend and Zeebrugge. The German flotilla has used the Zeebrugge Mole as a convenient sanctuary from which to launch Uboats and sink allied ships passing through the English Channel. By 1918, Britain was virtually held under siege by the menace of the German Uboats.

The German Flotilla

Public domain image of the wrecked British vessels
after the Zeebrugge Raid

The crews of the flotilla were looked upon with disdain, almost as pirates. Such an action as torpedoing passing vessels from the concealment of the sea was seen as unethical and cowardly. By this time, they had already sunk over 2,500 allied ships.

In order to block the Bruges canal entrance, Keyes perfected a plan to use retired mining vessels: HMS Thetis, Iphignia and Intrepid, which would become ‘blockships’ by scuttling. A storming of the Mole by means of HMS Vindictive with the aid of two Mersey ferries, HMS Iris II and HMS Daffodil would provide the diversion needed.

Scuttling Blockships

In the meantime, two submarines loaded with explosives would breach the Mole wall, providing access to the Bruges canal. Behind the resultant smokescreen, Vindictive would offload 200 royal marines who would disable the gun emplacements lining the Mole. The three blockships would also be scuttled in place, closing off the Bruges canal.

Keyes had already been to the Zeebrugge Mole in 1914 when on board HMS Lurcher during the Battle of Heligoland Bight, so he knew the layout of the area. He also knew the blockships had to have the right girth – just wide enough to enter the canal, but not so narrow that the smaller boats could pass through. Each blockship would be filled with concrete, making them virtually impossible to move once scuttled. Both Ostend and Zeebrugge would be raided simultaneously to give the enemy no chance to clear either end.

Zeebrugge Raid Outcome

Sadly, the outcome of the raid was vastly different to the plan. The wind changed direction during Vindictive’s approach, clearing the smokescreen and providing a clear view of the raiding marines. HMS Thetis was not scuttled in the right place, leaving the canal entrance partially open and allied marines suffered heavy casualties.

Despite the failure of the mission, Captain Keyes and his staff were lauded as heroes and Churchill declared that the Zeebrugge Raid was the ‘finest feat of arms’.