K26 was the last K-class submarine to enter service and incorporated all the changes that were needed to produce a successful steam & electric powered submarine from the original K-class. As designed the K-class were the fastest & most powerfully armed submarines in the world in 1916 when K3 entered service. On K26 the bow in front of the forward gun had been raised to make higher speed in heavy seas, the 4" guns had been raised to provide a better command and diving time had been reduced to 30 seconds. Some faults still remained, the bridge was too small and the number of hatches and valves to be closed tight before diving resulted in frequent small leaks when underwater. In service K26 was a useful addition to the fleet and was only scrapped in the late 1930s.