In December 1654 a large naval force departed from Portsmouth and sailed across the Atlantic. Its goal was to expand the English Commonwealth in the Caribbean at the expense of Spanish colonies. The Gloucester, a third-rate frigate recently constructed as part of Oliver Cromwell's ambitious shipbuilding programme, was one of the largest and most heavily armed warships of the expedition. Combining analysis of courts martial accounts, inventories, journals, letters, sailing instructions, and wills, this article argues for the Gloucester's importance as a case study and microcosm for understanding the economic, political, religious, and social problems that the navy and wider Protectorate faced. It revises traditional historiography about the topic that has underestimated the significance of the naval context to the Western Design. Crucial to this new history is that the extreme hardships and religious divisions created tensions that targeted the leadership of Admiral William Goodsonn. Of particular importance in this narrative is Benjamin Blake, captain of the Gloucester, who clashed with Goodsonn over key policies. By focusing on the Gloucester and exploring its crew's experiences, this article shows that the English navy was a restricted and internally conflicted force when operating at the peripheries of the state network.