Small gunboats sat outside the headline treaty limits. Their displacement, speed, and lack of torpedoes put them alongside sloops even though their six-inch guns gave them considerable local firepower. They carried no official armor, but crews could add improvised protection when the hull would bear the weight. Wartime refits introduced pom-poms, three-inch anti-aircraft guns, and 20 mm weapons. In 1939 Aphis and Ladybird exchanged their Mark VII six-inch guns for longer Mark XIII weapons removed from HMS Agincourt. Shallow draft opened rivers and close coastal waters to them, while poor seakeeping kept them out of rough seas.
Notable Point · 11:08-14:32
Why treaties barely constrained Insect-class gunboats
At under 2,000 tons, below 20 knots, and without torpedoes, the class sat in the treaty-era small-ship category despite its six-inch guns.