For the next seven years Plumridge served as a lieutenant; aboard the under Captain the Honourable Arthur Kaye Legge, in under Captains John Giffard and William Pierrepont, and then "Melpomene" again, under Captain Peter Parker. There, on 1 May 1809, during the Gunboat War, he commanded the boats of "Melpomene" in an attack on a Danish cutter of 6 guns and several merchantmen, which were lying under the protection of gun batteries in the harbour of Huilbo, Jutland. The cutter was destroyed, but with the loss of Lieutenant George Rennie, and five men severely wounded. Soon after "Melpomene" fought off an attack by a flotilla of 20 gun-boats, suffering considerable damage, and losing 34 men killed and wounded. He then served aboard the frigate , Captain Joseph Baker, in the Baltic.