- The stresses of heavy rolling can cause stacks of containers to buckle, damaging those lower in the stacks and causing those near the top to careen overboard.
- Vessels have also rerouted away from heavy seas, which have in the past been facilitated by Suez Canal and Red Sea transits.
- But with these waters compromised by Houthi attacks, shipping lines have had to brave the Cape of Good Hope instead.
Sailing around the Cape of Good Hope was regarded as foolhardy in the days of tall ships and wooden hulls. But even for the sophisticated vessels of today, there are dangers, reports the Loadstar.
Two recent high-profile container-loss incidents have reduced confidence in the suitability of massive containerships for tougher ocean conditions. And it could have been much worse: a bulk carrier was caught in another of South Africa’s late-winter storms, capsized, and broke up off Cape Town.
“The southern hemisphere is at the end of winter, heading into spring,” explained Mike Yarwood, MD of loss prevention at TT Club, who is investigating the Cape environs, with the help of colleagues in Durban.
He told The Loadstar: “I am trying to rationalize whether that means that the most high-risk period of the year has passed, or is passing now, or whether they expect a deterioration through their spring and summer months.”
Parametric rolling
One of the major contributing factors to the dangers around the Cape is ‘parametric rolling’, which occurs when the ocean’s surface’s wavelength matches the vessel’s rolling motion, gradually increasing the angle of each roll with every wave impact.
The stresses of heavy rolling can cause stacks of containers to buckle, damaging those lower in the stacks and causing those near the top to careen overboard.
To help avoid this, shipping lines plan to try to place heavier containers at the bottom of stacks, but as TT Club points out, studies have identified an alarming discrepancy, of around 20%, between stowage plans and actual stowage.
Vessels have also rerouted away from heavy seas, which have in the past been facilitated by Suez Canal and Red Sea transits. But with these waters compromised by Houthi attacks, shipping lines have had to brave the Cape of Good Hope instead.
Shipping will not escape the amplification of ocean condition changes based on climate change, either. A recent study by the Environmental Defence Fund found shipping’s climate-based annual costs could increase from $3bn today to some $7.5bn by 2050.
“Ships will never be able to avoid the impact of heavy seas entirely,” said TT Club’s Peregrine Storrs-Fox. “Consequently TT, in furtherance of its mission to make the global logistics industry safer, more secure, and more sustainable, continues with its efforts on this issue and urges industry colleagues to do likewise.”
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Source: The Loadstar
