HMS Truelove started her career as the Royalist 14-gun Katherine during the English Civil War.

She was captured by the 'Irish Squadron' of the Parliamentary Forces in early 1647, then purchased for 75.1.02d and fitted for service at Bristol.

[1] After King Charles II landed in Dover, she was assigned as the Medway guardship in June 1660.

On 15 March she was under the command of Captain William Peach, RN and stationed at the Downs during the Battle of Lowestoft on 3 June 1665.

Finally she was under the command of Captain Peter Bonamy, RN until the Battle of Texel in 1673 where he was killed.