1. Starter – What do you think this is?
Mark XI Depth Charge used by US Navy later in World War II. Unlike the cylindrical barrel-shaped depth charge used earlier, the Mark XI is streamlined and equipped with fins to impart rotation on the depth charge, allowing it to fall in a straight trajectory with less chance of drifting off target. This type of depth charge contained 200 pounds (90.7kg) of Torpex.

2. War At Sea

3. Learning objectives
To understand the role the Royal Navy played in WW1
To evaluate how the Germans used submarine warfare to disrupt supplies to Britain.

4. THE WAR AT SEA
The War at Sea during the First World War consists mainly of:
The impact of Germany’s U-boat campaign against the British merchant fleet and
The Battle of Jutland

8. The U-boat campaign: restricted submarine warfare
Germany made very effective use of its small U-boat fleet (only 23 at the start of the war).
At first, the Germans stuck to the rules of war by sinking only merchant ships belonging to Britain and her allies.
This resulted in a small number of sinkings: only ten by Feb
After Feb the Kaiser ordered a change of tactic.

9. Un-restricted submarine warfare, Feb-Oct 1915
From Feb the Germans declared that any ship in British waters (even neutral ones) would be attacked – this was unrestricted submarine warfare
Sinkings shot up – in August 1915 alone, U-boats sank 42 merchant ships.
One of their victims was the British passenger, the Lusitania, torpedoed in May, Among the 1200 civilian dead were 128 Americans
The sinking was a public relations disaster for the Germans and US opinion was outraged.
After the war, it became known that the Lusitania was carrying munitions for Britain – a breach of the rules of war

10. German propaganda disaster
The actual sinking of the Lusitania was enough of a disaster.
It was made even worse when a German medal-maker decided to cast a medal to celebrate its sinking.
The British circulated copies as further evidence of German ‘barbarism’.
The German government ordered all German copies to be destroyed – but too late.

11. April 1917: US enters the war
The Germans suspended their campaign in September 1915 because of the hostile reaction of neutral (especially American) opinion.
However, the British naval blockade of Germany’s ports was causing terrible shortages of food and there was pressure to resume the campaign.
In February 1917 the Germans resumed their campaign.
US opinion was further angered by the publication by the British of the Zimmerman telegram in the same month. In this secret telegram the German gov. promised Mexico three US states if they would declare war on the US!
This hare-brained scheme finally drove the United States to declare war on 6 April, 1917.

12. 1. What risk do you think the Germans were running with their un-restricted submarine warfare campaign?
2. Why, nonetheless, do you think they went ahead with it?
3. Why was the sinking of the Lusitania a public relations disaster for the Germans?
4. What does the poster suggest was another benefit for the British?

13. Fig 1 – Blockading Germany and supply lines to Britain.
Next lesson... The Battle of Jutland