This year, South Africa’s coastal waters have experienced a significant increase in weather-related incidents. The number of incidents this year has already matched the total from the past three years. This article examines the specific weather and navigational risks associated with rerouting off the Cape of Good Hope, identifies high-risk areas, and highlights the vessel types most susceptible to accidents and claims, reports Gard.
Massive shift in traffic
Some of the diversion away from the Red Sea started already shortly after the Hamas attack in Israel in October 2023, but most of the change in traffic flow happened after the Houthi’s seizure of the cargo ship Galaxy Leader on 19 November 2023, as shown in the graph below. The Galaxy Leader was the first vessel that was directly impacted by the Houthi attacks.
Hot spots for high waves
In general, the weather conditions outside South Africa are much more challenging than in the Arabian Sea. In fact, for each month from January 2023 till September 2024, both the total swell height and maximum wave height were higher off South Africa than in the Arabian Sea, according to data from Gard and Windward. For further details, see this Gard analysis. Admiralty Sailing Directions for this area also confirm the same, stating that abnormal waves may be experienced at any time of the year.
The below map shows the max wave height observed for different areas outside South Africa and in the Arabian Sea. The maximum wave height is highest outside Port Elizabeth followed by the waters off Cape Town and Saldanha. The area outside Port Elizabeth is also where we have seen most of the weather-related claims, as shown in our heat map further up.
Key risks and recommendations
Vehicle carriers and container vessels – the vessel types that in relative terms have constituted the biggest increase in traffic outside the Cape – have the highest frequency of weather-related claims, according to Gard’s H&M claims data for the period 2015-2023. This is partly due to the sheer number of cargo units these vessels carry, making them more susceptible to damage from lashing or stowage failures, and any failure in lashing or stowage on one unit can trigger a domino effect. Whether it is a container vessel, vehicle carrier, general cargo vessel carrying breakbulk cargo or any other type of vessel, cargo lashings should be able to withstand the anticipated weather and vessel motions, and the crew should have evidence to support this. Please refer to this guidance prepared by Minton, Treharne and Davies Limited on lashing and securing arrangements.
There are also other risks shipowners and mariners should bear in mind. Severe weather can cause vessels to lose propulsion, making them susceptible to the elements and potential hazards like collisions or groundings. In many heavy weather-related claims handled by Gard worldwide, there have been instances of either temporary or prolonged loss of propulsion. Such incidents often lead to the vessel being broadside to the waves, resulting in heavy rolling. If this occurs in a busy waterway, it poses a navigational risk to other vessels. In a few cases, vessels were not able to regain propulsion, and salvage/towage had to be arranged. For further details on the technical reasons for the loss of propulsion, please refer to this ABL guidance.
Lastly, we would like to emphasize the crucial role of proper weather routing. Analyzing the wave height data for vessels that have had a heavy weather-related claim off South Africa, it seems that they were unable to avoid high waves despite the availability of advanced weather routing tools and services.
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Source: Gard
