Page 7 - Bulletin 9 2005

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west storms drive massive swells onto the Cape Peninsula in winter and south-east gales
mean that summer offers little respite from treacherous winds. Upwelling of cold Atlantic

water in conjunction with warm summer air regularly results in the thick fog that “whites-
out” areas such as Table Bay. Faced with poor visibility, storms, and a landscape generally

devoid of easily recognisable landmarks, it is not surprising that sailors struggled to set safe

course around the southern tip of Africa. Furthermore, the lack of good harbours around
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Cape Town until the second half of the 19 century, coupled with South Africa’s rugged,
unsheltered coastline, makes it little wonder that so many ships met their fate here. Even
after infrastructure was put into place, small harbours were no guarantee of safety. In the

great gale of 1865 more than twenty ships were lost in Table Bay in just one night. (Figs
1.1 – 1.3.)

Navigators were not only faced with the problems presented by the weather, they also had
to make their way across vast tracts of ocean with outdated and often inaccurate charts.

Before Portuguese explorers began their great voyages of discovery, ships hugged the

coastlines traversing unknown and un-navigated stretches of ocean. Even once the sea route
to the East had been opened it would be centuries before accurate maps of the landmasses

en route were produced. Despite the fact that sailors could easily calculate their latitude by
determining the angle of the sun above the horizon, it was not until the second half of the

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18 century, when John Harrison perfected his accurate marine timepieces, that navigators
could accurately calculate longitude. The inadequate navigational tools meant that ships

could only calculate their position by dead-reckoning which was often no more accurate

than a few hundred nautical miles. Countless examples of shipwrecks resulting from
navigational error litter South Africa’s shores.

Charting South Africa’s coastline proved especially difficult. With a few exceptions, such

as Table Mountain, the coast is devoid of natural landmarks. The illustrations of the coast
as seen from passing ships show the uniformity of the coast. Even with the addition of

accompanying notes, the identification of mountain peaks and bays would prove difficult.