A collision took place on 16 December 1910 at Harwich between the special service vessel ELFIN and HMS C8. At about 0700, while it was still dark and a gale was blowing, ELFIN was leaving Harwich Harbour when she came into collision with the submarine which was bound for Felixstowe to renew petrol. ELFIN, which had liberty men on board who were being taken to the HMS THAMES, was struck under water and went down within seven minutes. Most of the men were rescued but five crew members of THAMES/ELFIN were lost.

Note that there was some confusion in records which suggested that four of the deceased may have been C8 crew, thus this account, but there has been no further evidence of this.