One of the reasons for launching the Third Battle of Ypres was a British desire to capture the Belgian coastline from the Germans.
This would prevent the German Navy from using Belgian ports as bases to attack and sink the merchant ships bringing vital supplies to Britain.
To this end, the planning for Third Ypres included an amphibious landing by the British 1st Division and a force of 9 Mark IV tanks (6 Male, 3 Female). It was code-named Operation Hush. Once ashore forces advancing from Ypres would link up with the landing force and together they would advance along the coast.
The landing was to take place in an area between Nieuwpoort and Ostend. This was a low-lying area protected by a sea wall.
The plan was to use warships to position one end of three separate 550 foot long pontoons on the beach. Troops, artillery and vehicles would move from ship to shore along them. The tanks would be used to cross the sea wall. Any wall would be a difficult obstacle, but this one had two extra challenges – it would probably be covered with slimy seaweed, and it had a curved lip on top facing the invasion force.
The wall’s designer was found to be a refugee in France. He was able to provide diagrams of his design to the British, allowing them to construct a replica for training and experimentation at Merlimont.
The seaweed would be dealt with by fitting oversized steel track spuds with sharp teeth. They would cut into the seaweed and provide extra grip.
The solution to the lip on the wall was a wedge shaped ramp. This would be pushed in front of the tank until it reached the wall and was forced under the lip, then the tank would drive over it. Other vehicles would be pulled up the ramp and over the wall by winches fitted to the three Female tanks.
Ultimately Hush never took place. It was dependant on British advances around Ypres. During August and September these were not significant enough to give commanders confidence that any forces landed would be reached before the Germans destroyed them, and the landings were repeatedly postponed. After the failure of the British attack on the 12th October Hush was finally cancelled.
Would it have worked?
Whether Hush would have worked is an interesting question. The ramps seem to have been successful in testing, although there was more doubt over the track spuds. However any mechanical breakdowns before the tanks had crossed the wall could have been catastrophic for the plan.
British experience of amphibious operations at this stage was minimal. The most challenging parts of such an operation are generally the logistics and coordination between land and naval forces. This may have posed problems for Hush, although the intention was that the landing force would be reached by other ground forces fairly quickly, so it could have been that these difficulties would have been overcome.
Denying the Germans naval bases in Belgium would have had only a limited impact. Although it would have made their operations more challenging, German submarines had the range to operate from ports in Germany and still threaten shipping around Britain.
Read more about The Battle of Passchendaele in Background and Planning, The Battle and Tanks at Third Ypres.