When, in 1487, Portuguese explorer Bartolomeu Dias became the first European to round what is today called the Cape of Good Hope, he named it "Cabo das Tormentas", or the Cape of Storms. Upon his return to Portugal, King John II renamed it "Cabo da Boa Esperança" (Cape of Good Hope) because it was the first concrete evidence that a sea route around Africa to the Indian subcontinent was possible. (It's also said that he wanted to encourage further exploration and settlement there, and felt that the new name would be more marketable!)
However, the stormy aspect of the Cape continues to make itself felt. Many ships have come to grief in the gigantic rogue waves for which the area is notorious. I remember going to the quayside in Cape Town in 1974 to inspect the Wilstar, a Norwegian supertanker that was clobbered by a rogue wave. It made a hole big enough to drive a double-decker bus through it!
It seems the storms are as bad as ever.
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.
Two recent high-profile container-loss incidents – the CMA CGM Benjamin Franklin lost 44 boxes with damage to another 30 in July, and 99 containers were lost this month from CMA CGM Belem – have reduced confidence in the suitability of massive containerships for tougher ocean conditions.
And it could have been much worse: a bulk carrier, Ultra Galaxy, was caught in another of South Africa’s late-winter storms, capsized and broke-up off Cape Town.
. . .
One of the major contributing factors to the dangers around the Cape is ‘parametric rolling’, which occurs when the wavelength of the ocean’s surface matches the rolling motion of the vessel, 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.
There's more at the link.
This is adding to the difficulties caused by the Houthi blockade of the entrance to the Red Sea off Yemen, which has caused many shipping lines to divert their vessels via the Cape sea route. Many of those ships were not designed for such conditions, being built specifically to cater to the requirements of the Suez Canal route, where weather is usually much less extreme.
I'm glad my seafaring days off the Cape are done. There were some memorable moments . . .
Peter
9 comments:
‘Parametric rolling’, or, in any other engineering discipline, 'resonance'. I am kind of shocked that the various natural frequencies of a ship, and the frequencies of the waves they encounter, aren't known well enough to avoid and/or mitigate this.
The sea will win the fight. It's like gravity is for aviation - the ultimate victor.
TXRed
@Hamsterman Presumably anyone with a Master's licence for a containership knows all the theory. I'd imagine that if roll frequency starts to get near resonance the procedure would be to turn orthogonal either way to the direction they're coming from. At least it's not the age of sail and you don't have the whole lee shore horror. But... shipping companies are run by MBAs who neither know nor care about these things. Everything is insured and the Filipino and Bangladeshis who work on them are easily replaceable interchangeable parts (such is the Managerialist mindset)... so doubtless instructions are to never deviate from course.
The real story is that the United (it is to laugh) States of America is toast as a global empire. Not everyone knows it yet... but anyone with a geostrategic outlook gets it. When you can no-longer guarantee freedom of navigation, that's it. Done. Toast.
For a myriad of reasons, technological, balance of powers, moral, morale, and more... the USA and its minions simply cannot just invade and create a new reality on the ground where the Houthis cannot close the Bab-el-Mandeb. The USN has not dared to pass the straits with a CVN and baggage for many months now. Has not DARED. There are strong rumours that the Eisenhower was damaged on its last deployment. X / Twitter users may be aware that the captain of that mighty emblem of American power is a prancing closet case who regularly tweets about baking cookies for the crew and invites them to the bridge to phone home to their mommies. You can't make this stuff up.
There will be all sorts of cope... but as guys like Giap said in days gone by... (paraphrasing) "It's all very well to blame running from VN on your domestic politics... fact remains here we are and you're gone and you LOST... @#$%ers. Face it or not. I'm here and you're gone. That's all that matters.".
It's Over, Red Rover. Something new will arise. The prime duty of the USA now is to accept it and deal with it gracefully and not lash out and burn up half the world in a paroxysm of narcissistic self-destruction.
They are known. The problem here is that due to political turmoil, the Suez Canal is too much a risk. The most expeditious alternative is a route around the Cape. But there is the risk of ships designed for more placid waters entering waters around the Cape. Disaster may occur. Often enough, it does occur.
Perhaps you would better understand the point by imagining a river barge now put to service across the seas. Further, not just any sea lanes but that around the Cape. What would you expect?
A factor not mentioned is the meeting of a cold water current (Benguela) with a warm water current (Agulhas). This creates a sea state which sometimes swallows entire vessels. Yes, swallows. As in gone without a trace. No oil slick, no flotsam or jetsam to mark it's passage.
The two currents are of differing salinity. That changes the buoyancy of, say a ship upon those waters.
Another factor which is dangerous to the safe passage is the contour of the sea bottom.
These factors and conditions are well known. Hull design is well along. But what are you to do, stay in port?
Do houthi live in mud huts.
The seas will always be dangerous, as the MV Estonia and Edmund Fitzgerald demonstrate.
My late father was stationed in India during WWII and returned to the USA on a Liberty ship to Baltimore. Some where on the voyage the ship started splitting at the bow. Rather than putting into a port for repairs, the Captain elected to continue, stern first at 3 knots, to Baltimore. As a lowly enlisted man, where the ship started coming apart he wasn't told, but he vividly remembered being in huge waves.
Some do. Irrelevant. They decide who passes the straits. You do not. Apparently you cannot stop them deciding who passes the straits. That it all that matters. Whether or not they have heated toilet seats, central air, and a refrigerator which dispenses 3 types of ice cubes signifieth not. They control one of the world's major trade arteries and there is nothing you (in base reality, not your hypothetical fantasies) can do about it. QED.
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