The Mark IV, delivered at the end of April 1917, was used successfully through the rest of 1917. It shouldered on through the war but was replaced over time by the newer Mark V and its various models.
A total of 1,220 were built: 420 “Males”, 595 “Female” and 205 unarmed supply tanks.
This model is a “Female” from Peter Pig.
The photograph below is a “Male” with the new unditching beam.