The gunboats were originally designed for harbour defence and assisting minelayers. By WW II, these gunboats were outdated due to their lack of anti-aircraft armament. They were assigned to simple guard duties in the northern territorial waters of Holland. Friso and Brinio on the IJsselmeer and Gruno in the vicinity of Terschelling. They could be quite effective with their (for their size) large main battery.
The Brinio was on 14th May attacked by a German Stuka and badly damaged. Scuttled by the crew. In October 1942 salvaged and dismantled.
Brinio was named after a leader of the German tribe of the Cananefaten who lived in Roman times in Holland.
type: gunboat, Gruno class gunboat
built: Rijkswerf Amsterdam, 16-10 - 1911
dimensions: 52,66 x 8,52 x 2,75 m
complement: originally 52, 63 (1940)
armament: 1 x 40 mm No.2,
2 x 12.7 mm Vickers
Münching, L.L. Koninklijke Marine in de 2e wereldoorlog, Alkmaar 1978. p 55.