1st March 1918
Western Front
Germans recapture trenches south-west of Butte de Mesnil, but fail in local attacks elsewhere in Champagne and near Reims.
Big German raids at Haucourt (north-west of Verdun) and Seicheprey (Lorraine), the latter against Americans.
Naval
British armed merchant cruiser
HMS Calgarian is torpedoed and sunk by the German U-boat U-19, killing 49 sailors.
Ship Lossers:
SMS A57 (Kaiserliche Marine) The A56-class torpedo boat struck a mine and sank in the North Sea with the loss of twelve of her crew.
Borga (United Kingdom) The cargo ship was torpedoed and sunk in the English Channel 9 nautical miles (17 km) south east by south of Beer Head, Devon (50°32′N 2°56′W) by
SM U-55 ( Kaiserliche Marine) with the loss of 5 crew.
HMS Calgarian (Royal Navy) The armed merchant cruiser was torpedoed and sunk in the Irish Sea off Rathlin Island, County Antrim (55°25′N 6°15′W) by
SM U-19 ( Kaiserliche Marine) with the loss of 49 crew.
Norefos (Norway) The supply vessel was scuttled in the Atlantic Ocean 60 nautical miles (110 km) off Dakar, French West Africa.
Penvearn (United Kingdom) The cargo ship was torpedoed and sunk in the Irish Sea 15 nautical miles (28 km) north of South Stack, Anglesey (53°35′N 4°49′W) by
SM U-105 ( Kaiserliche Marine) with the loss of 21 crew.
Sunrise (United Kingdom) The ketch struck a submerged wreck and sank.
HMT Thomas Collard (Royal Navy) The naval trawler was sunk by the force of the explosions of the torpedoes that sunk
HMS Calgarian ( Royal Navy), which was a victim of
SM U-19 ( Kaiserliche Marine). Her crew survived.