Go Back

When to Skip the Suez Canal for the Cape of Good Hope

Emily Heaslip

2020 proved to be a year that exposed the interconnectedness of global supply chains, with factory shutdowns in a given country wreaking havoc continents away (source). And now, in 2021, the effective shut down of the Suez Canal again exposed the fragility of our trade networks with a single ship--the Evergreen Ever Given--able to block a main artery for roughly 12% of all global trade (source). 

Even as the Ever Given is freed from its grounding, backups will remain, so the question for other ship owners and captains becomes when do they chart a new course.

Image: Courtesy of Planet Labs

When to Divert

The last time a closure of this magnitude occurred at the Suez Canal was from 1967 to 1975. This closure was triggered by the outbreak of the Six Day War, and the canal did not reopen until after the Yom Kippur War. During that eight year period, fifteen cargo ships remained trapped in the Suez canal (the Yellow Fleet), and ships were forced to transit around the Cape of Good Hope, adding thousands of miles to their voyages. We all remain hopeful that this latest shut down will not last eight years, but what goes into making the decision to change course?


Ships are on a schedule. With the canal closed, Lloyd’s List estimates that $9.6 billion in products transit the Suez Canal every day. Even after the Canal reopens, the length of a voyage through the Canal will increase, as late arrivals will need to wait for the 100s of ships ahead of them to sail through. As a result, for ships leaving port today, rounding the Cape of Good Hope may be the better option.


With the Canal closed, ships will consider longer routes, and likely steam faster to recover time lost. Moreover, sailing a longer ocean route exposed to Southern Ocean storms will inevitably lead to bigger waves, more resistance, and thus higher fuel consumption. This means higher fuel costs and a considerable increase in emissions. 


Ultimately, safety comes first. With rounding the Cape of Good Hope, vessels will be exposed to the rumble of the Southern Ocean. And as the Southern Hemisphere winter approaches, these waters can become dangerous to maritime traffic.

After the 1967 closure, for example, an increase in ships transiting the Cape led to an “alarming number of incidents involving extremely large waves” (source). The interplay between the mighty Agulhas current, wind, and seafloor topography can lead to intense wave energy that can result in unsafe conditions if captains are unprepared for the voyage.

How to decide?

With all these factors at play, the decision to divert is not an easy one. In particular, since it is not yet clear how long the canal backlog will take to process.

Data can help. To assess the costs in fuel, emissions, and the potential risks of taking the long way around the Cape, reliable weather forecasts powered by live, in situ data from the region are critical. The Sofar Spotter buoy network collects data across the Southern Ocean, particularly at points of maritime interest like the Cape of Good Hope, to generate accurate weather forecasts through assimilation into our global weather models

Combining these weather forecasts with extensive vessel performance data from each ship, Sofar’s Wayfinder product delivers to captains at sea what Google Maps does on land: real-time data ingestion and continuous end-to-end optimization to avoid heavy weather, reduce fuel costs, lower emissions, and stay on schedule.

Learn more about Wayfinder here

Access Sofar's global weather forecasts here

Sofar in the News

Deep sea thinking
Access insights from Sofar's team of ocean scientists to power your next deployment, voyage, or operation. Subscribe to our blog.

Related Stories