The Group Two K boats, K23 to K28 were ordered in June 1918 and were intended to be an improvement on the Group One boats. K23 to K25, K27 and K28 were cancelled on 26th November 1918, the frames of K24, K25 and K28 were ordered to be taken to HM Dockyard Chatham for completion but this was also cancelled finally.
The modification of the Group Two boats consisted of a new high-pressure system for blowing the forward external main ballast tanks. To improve seaworthiness a free-flooding structure was added forward which gave the appearance of a bulbous bow. One gun was removed and the other repositioned on the superstructure, deck torpedoes removed to improve the stability and the funnels were lengthened to reduce the amount of water being washed down into the boilers.
H.M. Dockyard Chatham
2 Electric Motors 400hp.