SAILING RIGS AND THEIR USE ON OCEAN-GOING MERCHANT STEAMSHIPS 1820-1910

The first paddle wheel propelled steamers to cross the ocean had insufficient bunkers to allow continuous use of the engines and therefore carried a modified sailing ship square rig. Even after the introduction of screw propulsion and larger iron hulls, if the range under steam was inadequate for the intended voyage, then a substantial sail plan was essential. The alternative was to carry an excessive amount of coal, to run the engine continuously and have a reduced rig with a high proportion of fore and aft sails, a solution that proved, in most cases to be uneconomic. The introduction of the compound engine in the 1860's which effectively cut fuel consumption by one third provided the breakthrough and from then on sails were seen as auxiliary to steam propulsion on all but a few long haul routes. In the next two decades sail area per ton displacement continued to decline, reflecting the ever increasing efficiency of marine engines and by the 1890's few steamships carried square sails. In another ten years even the remnants of fore and aft canvas had been abandoned on nearly all new-built ocean-going steamships. Despite a diligent search, it would appear that apart from the authors previous work on early 'sail and steam', and some recent publications that refer to the subject only briefly, this important aspect of steamship evolution has been largely ignored by maritime historians. It was however, at the time, discussed by a few seamen, marine engineers and shipbuilders with articles appearing in periodicals, scientific papers and reports from Institutions and these contemporary sources, along with ships' logbooks, private journals and the sail plans contained in the Denny List, form the main material for this research. This study has revealed that there were sound practical and economic reasons for the carrying of sail on steamships ranging from providing the main motive force to that of auxiliary, and even when engines were run continuously they could help reduce fuel consumption. Among other benefits, the most important function was as a fail-safe in the event of a complete breakdown, or running out of coal. These reasons alone were enough to convince the mariner that a single screw steamship engaged on a deepwater voyage without sails, was unseaworthy.National Maritime Museum, Greenwic