WWI had naval battles worldwide but only 1 major sea battle: Jutland (May 1916), w. 250+ ships. Some historians argue war was won/lost at sea since both Br. & Ger. relied on imports for food.
The U-boat campaign vs Br.
Ger. used U-boats to sink supply ships to Br.
1914: Focused on Royal Navy, sank 9 warships, but Br. tactics made attacks harder.
Also laid mines in Br. waters.
Feb 1915: retaliating vs Br. blockade, Ger. declared
submarine warfare zone (sinking all ships sailing to Br.).
Aug 1915: U-boats sank 2 ships/day. Br. relied on imports for food & war supplies.
Suspension of unrestricted submarine warfare (Mar 1916)
Risk: Neutral ships sunk → international outrage
US angered by sinking of Harpalyce (relief ship).
May 1915: sunk, killing 1,200 (inc. US citizens) → Wilson warned Ger..
Aug 1915: Arabic sunk, 3 US citizens killed → Ger. stopped unrestricted warfare.
Mar 1916: Sussex sunk → Wilson threatened to cut ties → Ger. issued ' Pledge' (no attacks on passenger ships, warning to merchant crews).
Anti-submarine measures
Br. developed countermeasures:
1. : Disguised warships lured U-boats to surface, then attacked.
2. : Type D introduced (Jan 1916), but lacked good detection tech (hydrophones underdeveloped).
3. & submarine nets: Placed in English Channel.
Effectiveness: Limited only 15 U-boats sunk by end 1916. Yet U-boats sank 25% of ships to Br.. 1917: Br. had only 2 months' flour left.
Resumption of unrestricted submarine warfare (Jan 1917)
1917: Ger. Admiralty wanted to resume U-boat attacks; said 600k tons/month sunk → Br. would surrender in 6 months.
31 Jan 1917: Kaiser agrees ∵ Admiral
promised: not one American will land on the Continent.
Feb 1917: Wilson cut ties w. Ger. but did not declare war (US isolationist mood).
Apr 1917: Zimmermann Telegram pushed US to declare war on Ger..
Anti-submarine measures (continued)
4. : from Apr 1917, merchant ships sailed in groups of 20+, escorted by warships w. depth charges → U-boats struggled to attack. By 1918, only 1 in 25 merchant ships sunk.
5. US assistance: American battleships protected convoys. US wheat shipments helped Br..
Effectiveness: Aug 1917: 211 ships sunk → 1918: losses halved, then fell rapidly.
The Battle of Jutland, May 1916
While U-boats targeted Br.s supplies, Br. blockaded Ger..
May 1916: Ger. fleet () attempted to break blockade, met Br. Grand Fleet ().
Ger. Govt feared Communist revolt → ended war.
∴ Jellicoe was defeated at Jutland = key to victory.
WWI had naval battles worldwide but only 1 major sea battle: Jutland (May 1916), w. 250+ ships. Some historians argue war was won/lost at sea since both Br. & Ger. relied on imports for food.
The U-boat campaign vs Br.
Ger. used U-boats to sink supply ships to Br.
1914: Focused on Royal Navy, sank 9 warships, but Br. ZIGZAG tactics made attacks harder.
Also laid mines in Br. waters.
Feb 1915: retaliating vs Br. blockade, Ger. declared UNRESTRICTED submarine warfare zone (sinking all ships sailing to Br.).
Aug 1915: U-boats sank 2 ships/day. Br. relied on imports for food & war supplies.
Suspension of unrestricted submarine warfare (Mar 1916)
Risk: Neutral ships sunk → international outrage
US angered by sinking of Harpalyce (relief ship).
May 1915: LUSITANIA sunk, killing 1,200 (inc. US citizens) → Wilson warned Ger..
Aug 1915: Arabic sunk, 3 US citizens killed → Ger. stopped unrestricted warfare.
Mar 1916: Sussex sunk → Wilson threatened to cut ties → Ger. issued 'SUSSEX Pledge' (no attacks on passenger ships, warning to merchant crews).
Anti-submarine measures
Br. developed countermeasures:
1. Q-SHIPS: Disguised warships lured U-boats to surface, then attacked.
2. DEPTH CHARGES: Type D introduced (Jan 1916), but lacked good detection tech (hydrophones underdeveloped).
3. MINES & submarine nets: Placed in English Channel.
Effectiveness: Limited only 15 U-boats sunk by end 1916. Yet U-boats sank 25% of ships to Br.. 1917: Br. had only 2 months' flour left.
Resumption of unrestricted submarine warfare (Jan 1917)
1917: Ger. Admiralty wanted to resume U-boat attacks; said 600k tons/month sunk → Br. would surrender in 6 months.
31 Jan 1917: Kaiser agrees ∵ Admiral HOLTZENDORFF promised: not one American will land on the Continent.
Feb 1917: Wilson cut ties w. Ger. but did not declare war (US isolationist mood).
Apr 1917: Zimmermann Telegram pushed US to declare war on Ger..
Anti-submarine measures (continued)
4. CONVOYS: from Apr 1917, merchant ships sailed in groups of 20+, escorted by warships w. depth charges → U-boats struggled to attack. By 1918, only 1 in 25 merchant ships sunk.
5. US assistance: American battleships protected convoys. US wheat shipments helped Br..
Effectiveness: Aug 1917: 211 ships sunk → 1918: losses halved, then fell rapidly.
The Battle of Jutland, May 1916
While U-boats targeted Br.s supplies, Br. blockaded Ger..
May 1916: Ger. fleet (SCHEER) attempted to break blockade, met Br. Grand Fleet (JELLICOE).