As the title of this thesis indicates, it is concerned with Bristol's sixteenth century shipping industry. The bulk of the study, however, is concerned with an intensive examination of the period 1539-46. It begins by examining the economic conditions of the industry in the mid-sixteenth century and the costs, risk and returns involved in entering the shipping market. It reveals that engagement in the industry, and particularly in the servicing of the Continental trades, involved high costs and considerable risks. Since, mechanisms to spread risk, such as insurance or shared ownership, were either unavailable or rarely adopted, engagement in the industry was in practice limited to the city's wealthiest merchants. Yet, although this may have limited aggregate investment, the small size of Bristol's shipowning community facilitated the creation of collective arrangement that aimed to further their mutual interests. The second chapter examines the size and nature of the city's shipping market. It reveals that the market for commercial shipping was split into two sectors - one serving the Continental trade to Biscay and Southern Iberia, and the other the lesser Irish trade. The primary focus of the chapter is the Continental shipping market. Its most significant and original conclusion is that while the demand for import shipping greatly exceeded the demand for export shipping in the city's declared trade, shipowners could rectify this imbalance if they were prepared to service the extensive illicit trades in grain and leather exports. Although this chapter focuses on the commercial demand for shipping, consideration is also given to the nature and timing of demand for shipping from non-commercial sources, such as privateers and the Crown. The third and fourth chapters examine how Bristol's shipowners maximised their returns during the years under study. Chapter three considers the years of peace from 1539 to February 1543. It reflects on the potential ways in which shipowners could increase their profits and considers the viability of these approaches. It is suggested that the two most important strategies they adopted were the operation of a cartel to raise prices and the servicing of the illicit trade, which allowed them to substantially increase the use of their ships at almost no extra cost.