Charles I had an effective large ship fleet as deterrent against the other European powers but few ships capable of defending the merchant fleet particularly from Barbary pirates who raided as far north as Britain. "Sallee [Morocco] inspired the only effective measure against Barbary raids, the 1637 expedition commanded by commoner Captian William Rainsborough". Rainsborough's vice admiral was Sir George Carteret "a naval gentleman, who in effect represented the Navy Royal" The expedition maintained a tight blockade of Salle New Town (modern Rabat) until it surrendered freeing 340 English captives. "Rainsborough's expedition was an unqualified success"
Safeguard reference: The Barbary Voyage of 1638 from the original manuscript of Sir George Cateret, ed. Boies Penrose (Philadelphia 1929)