They were originally to have carried sixteen 6-pounder carriage guns, but on 22 April 1795 it was instructed that they should be armed with sixteen 32-pounder carronades, although two of the 6-pounders were retained as chase guns in the bows.

The class was designed by one of the Surveyors of the Navy - William Rule - and approved on 22 April 1795.

Five vessels to this design were ordered in March 1795; the prototype was named Pelican on 11 June 1795 and the other five names were assigned and registered on 20 June.

In early 1795 the Admiralty identified the need for additional brig-sloops to meet the urgent need for convoy duties, and - as per their usual practice - commissioned two different designs, one from each Surveyor.

Fir-built vessels could be constructed more rapidly; hence five out of six of these were launched by the end of September 1795 (the Raven was delayed), when the two built of the conventional oak were still all on the stocks.