HMS Assiduous was the former pirate vessel Jackal, captured in 1823.

On 24 June 1824 Assiduous and HMS Lion captured a pirate schooner.

After HMS Lion, a tender to HMS Carnation, captured the slave ship Relampago, Carnation, Union, and Assiduous set out in pursuit of another slaver.

There the Spanish authorities refused to permit the British permission to seize her, despite an inspection revealing that she had carried slaves.

[1] Vice Admiral Lawrence Halsted, Commander-in-Chief, West Indies, ordered HMS Magpie and Monkey built on the lines of Assiduous.