Western Front
Artois: Second Battle of the Scarpe 1917 begins (next phase of the
Battle of Arras) (until April 24) (see also 9th and May 3rd): 9 British divisions (Third Army) with 2,685 guns (vs 1,329 German pieces), 20 tanks (5 disabled) attack on 9-mile front gaining 1-2 miles north and south of river Scarpe; 63rd (Royal Navy) Division repulses 5 counter-attacks at Gavrelle; 15th Division captures Guemappe. British capture 2,500 PoWs (another source claims only 1000) but lose 10,000 casualties.
Aisne: Poincare urges postponing offensive.
68 Royal Flying Corps fighters on offensive patrol for ground attack’s renewal. An hour-long massive ‘dogfight’ without any fatal casualties. But elsewhere, Ball makes 2 kills. Richthofen’s Jasta 11 scores its 100th victory (of 350 in war, top German unit score).
German soldiers take cover inside the trench from enemy grenades:
https://i0.wp.com/ww2-weapons.com/w...raben.jpg?ssl=1
French railway artillery in action near Muizon. © IWM (Q 56898):
https://twitter.com/CenturyAgoToday...3893377/photo/1
Naval and Overseas Operations
Atlantic: Battleship
New Mexico (BB49) launched at New York Navy Yard. First battleship with turbo-electric drive (completed May 20, 1918).
North Sea: 3 Royal Navy Air Service seaplanes bomb 5 German torpedo boats off Zeebrugge, sink 1.
Asiatic and Egyptian Theaters
British forces capture the city of Samarrah, Mesopotamia (Iraq) and its strategic rail yard from the Ottomans.
Political, etc
France: French government threatens to put German prisoners on board hospital ships if U-boats continue attacking those ships.
United States: “The Butcher Boy,” a short comedy film starring Roscoe Arbuckle and Buster Keaton, is released:
https://archive.org/details/busterkeatonthebutcherboy
Diplomatic relations broken off between U.S.A. and Turkey (no state of war followed).