Ordered under the 1908/1909 building programme, C33 was laid down on 29 March 1909 and launched on 10 May 1910 by Mrs Ommanney,
wife of the Admiral Superintendent, Rear Admiral Robert N. Ommanney.
.
When WW1 started, C33 was part of the Fourth Flotilla in Dover and under the command of Lt. G. E. B. Carter.
In January 1915 C33 was operating from Harwich with orders to entrap German Submarines acting from Ostend
and Zeebrugge.
On 4th August 1915 operating off the coast of Yarmouth with the Trawler Malta, she was lost with all hands when she hit a mine.
The history of this submarine is still being researched.