Is Durban to Cape Town

Best time:

January to March

Tropical storms:

Charts:

US: 61003, 61000

Pilots:

The best time to make this passage along the South African coast is between January and March, when weather conditions can be expected to be the most benign. Few people attempt to make this passage in one go without seeking shelter in one of the few good ports en route. In fact the lack of sheltered anchorages is only one of three factors that make sailing along this section particularly difficult, the other two being the Agulhas Current and the unpredictable weather pattern. The Agulhas Current runs in a SW direction following the 100 fathom (200 metres) contour of the continental shelf and can attain up to 6 knots in places. The weather around the southern extremity of the African continent is greatly influenced by pressure systems moving NE from the Southern Ocean. As mentioned in route IS52, a SW gale combined with the strong south-flowing current can create giant waves up to 60 ft in height and even higher.

It has been established from research carried out into the formation of these freak waves that in all cases the dominant waves came from the SW. This always appears to coincide with a specific weather pattern, when areas of low pressure move along the coast in a NE direction. It is not uncommon during such conditions for the wind to suddenly change from a near NE gale to a full SW gale, the wind reinforcing the existing wave pattern which acts against the Agulhas Current. Usually the largest waves occur between the edge of the continental shelf and an area 20 miles to seaward and this is the reason why mariners are advised to move inshore inside the 100 fathom line as soon as there is a sign of an approaching SW gale. Although coastal passages are outside the scope of this book, the area under discussion has caused so many nightmares to small boat voyagers that the Durban to Cape Town route has been considered in sections.

Durban to East London (250 m)

As there is absolutely no safe shelter along this stretch of coast, it is essential to leave Durban with a good forecast. It is recommended to leave Durban at the end of a SW gale when the barometer has topped out around 1020 millibars. On leaving Durban one should head straight for the 100 fathom line to take full advantage of the strong south-setting current. Should the weather deteriorate unexpectedly, one must close with the shore immediately so as to avoid the worst of the waves.

East London to Port Elizabeth (120 m) The same rules for leaving apply as for the run from Durban south with the proviso that if the weather is still favourable when level with East London and the barometer is not falling dramatically, it is better to continue to Port Elizabeth rather than stop at East London. In case of a sudden deterioration of the weather, the same kind of avoiding action should be taken as described earlier. It must be stressed that the Agulhas Current is very strong between these two ports and also that there are inshore setting currents into some of the bays en route.

Port Elizabeth to Mossel Bay (170 m) This section presents less problems than the previous ones as there are several places en route where one can shelter from a gale. One of the first of these ports is Knysna, although the entrance is quite difficult because of the strong tidal currents and can become hazardous during a SW gale when heavy swells break across the entrance. Shelter can also be found in Mossel Bay, near Cape Seal in Plettenberg Bay, and close to Cape St Francis, where one should beware of uncharted reefs.

Mossel Bay to Cape Town (195 m)

There are several places where one can anchor safely during unfavourable weather and on no account should Cape Agulhas be rounded in bad weather. There are onshore setting currents near all headlands on this route, which are also fronted by reefs, making navigation very difficult, especially in poor visibility.

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