The work of Coastal Command was unusually hazardous with a high rate of losses throughout the war, its work often neglected by comparison with Bomber Command:
On the 18th April, an aircraft on routine patrol sighted a convoy of eight merchant vessels off Stavanger; two formations of Blenheims from Coastal Command were sent out, in the morning and afternoon respectively, to attack this convoy. As a result of the first patrol a 7,000-ton vessel is believed to have been hit, and a 3,000-ton vessel was hit twice and seen to be rapidly sinking; two of our aircraft were lost. During the second patrol the Blenheims were attacked by five Me. 110, three of our aircraft being shot down, but all were able to drop their bombs and a direct hit is estimated on another ship.
From the Air Situation Report for the week, TNA CAB 66/16/15, which also records that Bomber Command was engaged against shipping during this period:
On each day of the week formations of aircraft have been sent out from Bomber Command to attack enemy shipping, with the following results :—
7,000-ton M.V. believed hit off Brest.
800-ton ship off Hoedenserke seen to disintegrate.
4,000-ton M.V. off Heligoland believed hit ; was last seen with large columns of smoke issuing from amidships.
5,000-ton M.V. off Heligoland, attacked from 50 feet and left on fire listing to starboard.
A Flak ship off Heligoland probably hit.
7,000-ton M.V. off Texel received two hits and was seen to have a list of 35 degrees.
6,000-ton M.Y. off Terschelling was probably hit.
5,000-ton M.V. off Scheveningen was attacked from 100 feet and was left sinking.
3,000-ton M.V. off S.W. Norway was hi t ; the ship stopped and was down by the stern.
2,000-ton cargo ship N.W. of Stavanger was hit, resulting in an explosion aft of the funnel with considerable smoke and steam issuing from the ship.
8.000-ton M.V. off the Dutch Coast received three direct hits and was last seen with clouds of smoke and steam issuing from it.