Container ship breaks in half and sinks

In post #52 it was asked if there was a rule of thumb for figuring out what size tug can tow what sized ship.
I have gone through our extensive library and cannot find any rule of thumb only that a tug of bollard pull 90 tons wil exert a tug of 150 tons on the tow line when towing a 100,000 tonner at 4 knots.
All ships these days have to have their mooring bitts marked with there SWL due to a number of accidents where tugs have literally pulled the towed ships bitts off the deck due to them exerting greater bollard pull than the bitts can withstand.
Tankers of a certain size have to have an emergency towing arrangement situated fore and aft and I guess that the max. bollard pull that can be exerted on these arrangements will be stated in their manual.
Bollard pull for a tug is measured by hooking up to a fixed point and with a tow line of (I believe) 100 metres, going ahead (and astern) at the maximum continuous rating of the tugs engines and propulsion system, measuring the starin in the tow line. Water depth etc also has to be at least 20 metres.
So the answer has to be, engage a tug that has a bollard pull equal to the swl of your shipps bitts or at least get the tug boat skipper to only tow at a lower speed and thus lower bollard pull.
rgds
JA

there is a lot more to it than meets the eye, same as loading and discharging bulk cargoes, never realised the complexity of it all, nice to have these explanatory posts.

bow section has broken away from tug, due to weather conditions, she is not being towed from her bow, but from aft where she snapped. At very low speed, latest from gcaptain. HER POSITION SHOWN APPEARS CLOSER TO INDIA, NOT OMAN,

Home | World Shipping Council
Regarding weights of containers loaded on board these big container vessels.
The link above (if it works) shows how concerned the industry was regarding the true weight of containers loaded on board. In the U.K. the MCA has made mandatory weighing of all containers before been loaded on board (this pprocess started after the Riverdance incident but only applies to passenger and RO-RO ships (MSN 1393 available on the MCA website).
So even today I guess that there are a relatively large number of places around the world where overweight containers are still been put onto ships with the possible overstressing and/or loss of stability.
When the IMO gets its bum into gear then legislation will no doubt be produced to force all terminal operators to weigh each and every container that it receives into its export terminal and this true weight transmitted to the cargo planner and ship in order that it can be stowed correctly.
These incorrectly declared weights of containers cause major losses and not just of ships. Stows can collapse as they are over loaded, loss of containers at sea due to the lashing not been capable of holding the overweight container, etc. etc.
rgds
JA

New Photos, Tow re connected from the Bow. ETA Salalah Oman 18 days at 2knots.Attachment 13081courtesy of gcaptainAttachment 13082

John A , ref yr post # 94 , just a few wee points ;

" Legislation will no doubt be produced to force all terminal operators to weigh each and every container "....... I can assure you that
the sticking point is the shipper. One of my previous jobs was terminal manager of a large container terminal and our weigh
bridge was always on and ready but no shipper was willing to pay the small weighing charge. I used to do spot checks on my own
account but it is the shipper who must be forced not the terminal.
Overweight containers are a problem as old as the history of containers thenselves but affect all containers and not just those in
a position to cause the collapse of a stow with consequential loss overboard. Same argument with lashing gear.
In my experience the biggest problem resulting from overweight containers is the exceeding of permitted stack weights especially
on deck where the moment of inertia can also be greatly increased.

Regarding the incident which is the subject of this thread , my own private point of view is that overweight containers were not
the main cause of the accident. Such containers would need to be confined to one or two bays or all to be loaded in one port ,
possible but highly unlikely.
Stand by my previous point regarding load/discharge cycles.

MOL Comfort Incident Photos [14 PHOTOS ]

JUST SENT THIS:

On June 17, Mitsui O.S.K. Lines’ MOL Comfort began suffering from severe hogging and broke in two while underway from Singapore to Jeddah with a load of 7,041 TEUs. As of today (3 JUL), bow section remains afloat and is under tow. The stern section sank on June 27.

Checked before posting, guess it is in the correct thread ?

LINK: MOL Comfort Incident Photos [14 PHOTOS] | gCaptain

K.

Not only overweight but weight distribution within the container. Have a dozen or so containers with uneven weight distribution and these containers up on the open deck and who knows what effect they could have on the ships trim.

In my experience. Cranes S.W.L. 3tons to 400 tonnes .Were fitted. with warning Bells and a cut-out switch. Does that safety procedure no longer obtain?

With all those Hyundai containers on board there are going to be an awful lot of people waiting for cars and spare parts.