Insect-class gunboat
The Insect-class gunboats (or large China gunboats) were a class of small, but well-armed Royal Navy ships designed for use in shallow rivers or inshore. They were intended for use on the Danube against Austria-Hungary (the China name was to disguise their function). The first four ships—"Gnat", "Mantis", "Moth" and "Tarantula"—were first employed during the Mesopotamian Campaign of the First World War on the Euphrates and Tigris rivers. Design. The ships were designed by Yarrow to operate in shallow, fast-flowing rivers, with a shallow draught and a good turn of speed to counter  river flow. They were fitted with two reciprocating (VTE) engines operating two propeller shafts to offer some redundancy. The propellers were housed in tunnels to minimise the operating draught. The main armament consisted of two 6-inch guns in single mountings fore and aft. Deployment. "Aphis", "Bee," "Ladybird" and "Scarab" were deployed to Port Said, Egypt in 1915–16, "Gnat", "Mantis", "Moth" and "Tarantula" were sent to the Persian Gulf in 1916. "Glowworm", "Cicala", "Cockchafer" and "Cricket" were deployed to the east coast of England in 1916 and had their main armament mountings modified to give higher elevation for anti-Zeppelin  work. In 1919, during the Russian Civil War, "Glowworm", "Cicala", "Cockchafer", "Cricket", "Moth" and "Mantis" served on the Dvina River (northern Russia, in Arkhangelsk Oblast), fighting in support of White Russian forces. "Glowworm"s captain and some other crew members were killed when a nearby ammunition barge exploded. The crew of "Cicala" mutinied, as part of a wider wave of unrest in the Royal Navy and five "ringleaders" were sentenced to death, later commuted to five years' imprisonment. Between the two world wars, the class were mainly used in the Far East and they were present during the Japanese invasion of  China. In 1937, on the Yangtze river, the Japanese attacked , firing on her from a shore battery. A US gunboat, was also attacked by Japanese aircraft and sunk. "Ladybird" sailed the to the scene of the sinking, rescued some of the "Panay" survivors and took them to Shanghai. "Scarab" and "Cricket" were off Nanking in 1937 as the Japanese started to bomb the city. In 1939, the original two 6 inch Mk VII 45-calibre guns on and "Ladybird" were replaced by more modern and longer 6-inch Mk XIII 50-calibre guns from the decommissioned battleship . At the start  of the Second World War, three vessels, "Cricket", "Gnat" and "Ladybird", were transferred to the Inshore Squadron of the Mediterranean Fleet. They joined the monitor and provided bombardment support for the Eighth Army. Their shallow draught allowed them to act also as supply and landing vessels, able to get close to beaches. In June 1943, "Aphis" took part in the bombardment of Pantelleria (Operation Corkscrew).