2026-06-25 –, Room 208 (Seats 40)
The global circulation of trading vessels in the late age of sail depended on a host of technological and environmental pre-conditions. One was ballast, a heavy, dense material placed in the hull of ships to ensure stability against the lateral force of wind and wave. In most regions, some mixture of stone, gravel or sand served this function and elaborate mechanisms emerged to supply and safely dispose of discarded ballast to protect harbours and navigation channels. In many long-distance trades, mariners sought alternatives in commercial goods that could also perform the ballast function, frequently referred to as saleable ballast. The East India Companies, for example, frequently shipped saltpetre and cowry shells to Europe rather than the “dead freight” of stone ballast. A somewhat distinctive trade in iron ballast, referred to as kentledge, emerged in England in the seventeenth century for East Indiamen sailing to Indian Ocean ports. While the intention was to sell iron bars on arrival in south Asia, over time the East India Company came to rely on kentledge as a ballast that circulated through the complete voyage cycle, travelling from England to Asia and back again. In the early eighteenth century, the British Navy similarly adopted kentledge as an important ballast material; by the end of the century, other world navies began to carry kentledge as well. This paper explores the emergence of kentledge as an important long-distance trade and naval technology, and considers its virtual absence from the historiography of global commodity trades and naval expansion. Rather than fully displacing stone ballast, or offering a saleable ballast as may have been the original intention, kentledge emerged as an important, complementary technology that compressed the space needed for stone ballast with important implications for trade and naval practice.
maritime history; east india company; British navy; global commodity trades; history of technology; environmental history
Matthew Evenden is a Professor of Geography at the University of British Columbia. A specialist in the history of rivers, most of Evenden's work has focused on modern Canada and North America. His current project, by contrast, follows the global history of ballast use in the late Age of Sail.