The Courser class was designed by Sir William Rule, the Surveyor of the Navy and although at first intended as gunboats, and therefore only had numbers, on 7 August 1797 they were reclassified as gun-brigs, and were given names.

The class were fitted with a Schank sliding keel and armed with ten 18-pounder carronades and two long 24-pounders.

[2] Defender shared with the sloop Dart and the gunboats Cracker, and Hasty in the proceeds of the capture of Hell Hound.

[3] This may have occurred on 7 October when Dart, Defender, Cracker, Hasty, and the schuyt Isis cut out four gunboats from the Pampus, in the Zuiderzee.

The "Principal Officers and Commissioners of His Majesty's Navy" offered "Defender Gun-Vessel, 168 Tons, Copper-bottomed, lying at Sheerness" for sale on 9 September 1802.