Blowin’ In The Wind
Square sails: The earliest known picture of a sail,
found on an Egyptian vase dated to about 3100 BC,
shows a simple square design. The material is
uncertain but the sail probably was made of animal
skins.
Egyptian, Roman, Greek, and Norse ships
commonly used square sails with corner eyelets
and a rope border. A spar held
the sail at the top and rope
pulled the sail taught at the
bottom corner eyelets. Later a
spar at the bottom was added.
Square sails work fine for
sailing with the wind but do not
work well for tacking into the
wind.
Lateen sails: Arab ships first
used lateen sails shaped like a
right triangle. Along the vertical,
the top and bottom corners
were attached to the mast and
a boom stretched the sail out.
This design allowed ships to
sail faster and closer into the
wind than square sails. Below
at right is a graphic of a Portuguese “Catalan” from 1370 with two triangular sails.
As sail design progressed, larger and larger sails gave way to smaller and more numerous sails
that could be better handled by a crew. In 1746 British sail makers were required to label new
sails with the maker’s name and address and bolts of sailcloth were standardized to twenty-four
inches by thirty-eight yards. Stitched from multiple strips cut from the bolt, sails were edged with
hemp ropes to provide anchor-points, distribute stress and help the sail maintain its shape.
Blowin’ In The Wind
Sail material: Viking longships used
square sails made of wool. A piece of
woolen sail with eyelet, radiocarbon
dated to between 1280 and 1420s, is
shown at right. Norwegian sheep
have wool with a relatively high
lanolin content, a quality useful for
sails and sea-going textiles.
Conventional thinking is that woolen
sails were “leaky” and could not beat
into the wind, but recent analysis of
the sample at right and other
evidence suggests “woolen square
sails could beat at 66 ° into the wind
and most likely out-perform linen and
hemp sails” (Cooke et al., 2002).
Fabric for sails through the mid-nineteenth century
included wool, but finely woven linen, made from
flax, and a more coarsely woven fabric made from
hemp came into broader use. Evidence from the
Vasa (below, right), which sank in 1628, shows linen
sails were in use at that time.
Holland was a major supplier of sailcloth and traded
both flax and hemp. “Zeildoek” in Dutch means
sailcloth, and eventually the word “duck” in English
became associated with the heavy fabric we know
today. Linen was supplanted by cotton during the
19th century.
References
Cooke, B., C.
Christiansen, and L.
Hammarlund. 2002.
“Viking woollen
square-sails and
fabric cover factor,” in
The International
Journal of Nautical
Archaeology, 31.2:
202-210.
Vasa