USA: PERSHING APPOINTED C-IN-C AMERICAN EXPEDITIONARY FORCE (AEF).
France: Ribot cabinet decide to make Petain C-in-C but Nivelle refuses to go on May 11.
Somme: British advance on south bank of river Scarpe.
Atlantic: First Allied general trade convoy (trial) sails (16 ships in 3 columns at 6 1/2 kts from Gibraltar with 5 escorts), reaches Plymouth unscathed on May 20 after 8 destroyers meet it 200 miles from Channel (May 18).
North Sea: German battlecruiser Hindenburg (launched August 1, 1915) joins High Seas Fleet.
Britain: House of Commons secret session on U-boat menace until May 11. Unofficial strikes involve 160,000 engineers (including London bus drivers on May 13) against dilution on private work (until May 24). 8 strike leaders arrested (released on May 23 after Munitions Minister meets shop stewards on May 19).