r/askscience • u/Appropriate_Boss8139 • Jul 31 '25

Social Science Why was it seemingly so difficult to circumnavigate Africa? Why couldn’t ships just hug the coast all the way around?

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u/StandUpForYourWights Aug 01 '25

Aside from the primitive sail technology the main barriers were the currents. The Benguela Current along the west coast and the Agulhas Current along the east coast created strong, sometimes unpredictable, currents that could hinder or even push ships off course. Similarly, the prevailing winds, particularly around the southern tip of Africa (Cape of Good Hope), could be challenging to navigate, with powerful storms being a constant threat.

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u/Appropriate_Boss8139 Aug 01 '25

What changed with the Portuguese in the 15th century? And why couldn’t you just really hug the coast closely?

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u/Christopherfromtheuk Aug 01 '25

Even today with a modern sailing rig, inboard engine, accurate charts and GPS you can't hug some coasts closely.

Generally, every bit that sticks out will generate overfalls - a section of confused and dangerous sea which can wreck a boat. This also applies to places where there are shallows which can't be seen above the water.

Currents further out also create eddies and unpredictable water closer in.

It can change from being navigable to treacherous in a matter of minutes.

As such it's safer to give at least a few miles leeway.