Windward Sailing Capabilities of Ancient Vessels

Abstract

Weatherliness is widely considered to have been an important ability for ancient sailing vessels, yet little firm experimental or theoretical data on the matter is available. However, by drawing on a variety of sources of model-test data and trials of fullscale replicas, it is possible to establish a general picture of what might have been possible. It appears that while ancient sailing vessels may have been capable of modest windward performance in moderate conditions and with a freshly-cleaned hull, this capability quickly disappeared as the hull became fouled and/or the wind and sea conditions deteriorated.

The Potential Performance of Ancient Mediterranean Sailing Rigs

“…The modern, global yachting industry has accrued a large body of knowledge relating to the bermudan rig currently favoured by most classes of yacht involved in organised racing (Marchaj, 1996: 152). There is now a growing body of literature and test‐results relating to the performance of other, more traditional, sailing‐rigs and reconstructed historical vessels (for example Crumlin‐Pedersen and Vinner, 1986; Brandt and Hochkirch, 1995; Nomoto et al ., 2003; Englert, 2006; Bennett, 2009; Palmer, 2009a; Palmer, 2009b). However, there remains no direct comparison of the square‐sail and lateen/settee rig.…”

“…The hull‐form of a vessel has a large influence on its performance, particularly on upwind courses. Put simply, the deeper in the water and more developed the keel of a vessel, the better its performance will be to windward (Palmer, 2009b: 316–18). The projection of the keel helps to resist the lateral forces imposed on the vessel during sailing.…”

“…Evidence of the effect of increasing the depth of keel comes from the sailing‐trials of half‐scale reconstructions of the Sutton Hoo and Graveney boats (Gifford and Gifford, 1996; cf . Palmer, 2009b: 316–18). Although half‐scale, the performance of these vessels can still be considered in this study, as vessels rigged with square‐sails, rather than representing the real performance of either the Sutton Hoo or Graveney vessels.…”

“…One of the major determinants of the extent to which a vessel rigged with any type of sail‐plan makes positive ground to windward is the state of the sea (Monfried, 1935; Gillmer, 1979: 179; Heikell, 1989: 23; Smitt, 1986: 172; Vinner, 1986: 222; Palmer, 2009b: 329). Generally speaking, the calmer the water the better the vessel will perform in a windward direction.…”

“…With light winds and calm seas, the Hanse Cog reconstruction was able to make 0.63 knots Vmg to windward. In much stronger winds and associated rougher seas, the vessel actually lost ground and made −0.1 knots Vmg (Brandt and Hochkirch, 1995: 7; Palmer, 2009b: fig. 18).…”