In 1915, two Admiralty gunboats were launched at South Docks in unusual circumstances. Built by Sunderland Shipbuilding Co, they were probably the only ships to be launched directly into the open sea at Sunderland and the last to enter the water broadsides.
They were the Insect-Class river gunboats HMS Moth and HMS Mantis, which were launched in 1915. A dozen were built during World War One by various UK shipbuilders.
All were identical in design, being 237 feet six inches in length by 36 feet beam.
The others were named HMS Aphis, Bee, Cicala, Cockchafer, Cricket, Glowworm, Gnat, Ladybird, Scarab and Tarantula.
Their shallow draught allowed them to operate on fast-flowing rivers using powerful triple expansion steam engines and triple-rudders helping to counteract strong currents.
Designed by the world famous Yarrow shipbuilders, all sister ships were equipped with two six-inch guns, one or two 12-pounders and six machine guns.
Owing to high wartime demand for merchant output, Sunderland Shipbuilding Co came up with a novel idea of freeing up conventional berths by building Mantis and Moth on the beach to the north of its main yard, which was situated on the northern side of the South Outlet next to Bartram’s.
The vessels were constructed together, end to end. HMS Mantis was launched into open sea on September 14, 1916, followed by HMS Moth on October 9. After the launch of Mantis, sliding ways were positioned beneath HMS Moth, which was then winched for some yards to clear a breakwater.
It had been intended that all the gunboats would sail for Salonika (now Thessaloniki) in Greece to take part in the allied campaign in support of Serbia against the combined forces of Germany, Austria-Hungary and Bulgaria. There, they would be dismantled and transported in sections to be reassembled for service on the River Danube.
Ordered and constructed as “Chinese River Gunboats,” this was a ploy to conceal their true purpose.
Unfortunately, the course of the war in the Near East led to abandonment of these plans and the gunboats being deployed elsewhere.
Both Mantis and Moth became involved in a range of duties, at first being shipped to Persia to help protect Anglo-Persian Oil Company’s refinery at Abadan. Afterwards they were sent to reinforce the Royal Navy on the Tigris near Baghdad during the allied campaign against the Ottoman Empire.
At the end of the war, both ships went to Russia in support of White Russian forces against the Bolsheviks.
By 1920, Moth was at the China Station, when in 1941, she was captured by the Japanese at Hong Kong and was renamed Suma. She was mined and sunk in the Yangtze in 1945.
HMS Mantis was scrapped in China in 1940.