 On the outbreak of the First English Civil War, he joined the Parliamentary fleet under the Earl of Warwick.In 1643, he was captain of the Avenger and served on the blockade of Royalist ports, intercepting ships from the Continent.Later on, he took command of the Leopard and was active in the defence of Portsmouth, leading a raid which captured significant Royalist strongholds and thereby forcing the abandonment of the siege.