In July 1917, a Coastal class airship set a new world record for a maritime patrol. This lasted for more than 24 hours, although a normal service lasted around 20 hours.
The C-9 was the most successful Coastal airship, had one confirmed “kill” and three probable “kills”. In only 15 months of service covered more than 68,000 miles in 3,700 hours of patrols.
Certainly their appearance was not very graceful, so they earned the nickname of “the ugliest airships ever built”, which did not prevent them from rendering a valuable service escorting maritime convoys.