Two Maersk Supply Vessels Sink En Route to Scrapyard


Figure 6: Towage at noon on 21 December 2016 leaving the English Channel at the Celtic Sea.
Source: Private photo

Figure 9: Excerpt from risk assessment for MAERSK CHANCELLOR’s towing of MÆRSK SEARCHER and MÆRSK
Source: Maersk Supply Service


There are similarities between this incident and the grounding of the Kullak. In the case of the Kullak the regular marine superintendent was on vacation and a towing plan that was created for a summer tow was approved for the winter tow by some office drone with little or no experience.


From page 35 of the report.


risk factors and risk mitigating initiatives were all
identified on the basis of the MoC meeting parti-
cipants’ experience and conceptions of what type
of risk scenarios would be relevant. As no partici-
> pant in the MoC meetings had experience with the
> side-by-side towing method, they relied solely on
their ability to imagine which scenarios could occur.

Tug side

The crew on MÆRSK BATTLER were aware that
> the side-by-side towing method was untraditional
> for this type of voyage. However, the crew strongly
identified themselves with the company’s image of
being industry frontrunners and capable of solving
difficult and novel tasks. Therefore, the crew did
not question the towing method, but relied on their
professionalism to manage the situation.


From the report:

Often, accident investigations focus on a short timeframe leading up to the accident
events and focus on actions taken by persons directly involved in these
events. In a case like the capsizing and foundering of MÆRSK SEARCHER
and MÆRSK SHIPPER, the towing operation and voyage were preceded by
nearly four months’ preparation involving a large number of persons. To gain
a more comprehensive understanding of the accident, the DMAIB therefore
needed to broaden the investigation to include the organisational processes
that took place in the shore organisation months before the accident occurred,
as these are tightly coupled to the events unfolding on the night between 21
and 22 December 2016.

In other words, the DMAIB regards the foundering of MÆRSK SEARCHER
and MÆRSK SHIPPER as a systemic accident. This means that local and
technical circumstances unfolding on board the MÆRSK BATTLER during
the voyage cannot be isolated from the preceding organisational events and
circumstances taking place months earlier, but together constitute a complex
system. The cause of accidents unfolding in such a complex system cannot
be reduced to singular factors or root causes. Instead, accidents emerge from
a unique conjunction of events and circumstances in which no single individual
can have complete knowledge of the processes and predict future events
emerging from these.

Damn, that’s good.




I read and reviewed the accident on my website a while ago and really you have to read the whole thing to get the idea. But surely no-one with any sense would have let that tow out of the harbour. At th end of my summary this was my comment:

"Words fail me really, and while I agree with almost everything the DMAIB have said, I find myself wondering about the view that the Maersk Chancellor was not equipped to carry out the “double tow”. According to my website all the C Class which were once OIL ships were equipped with two tow drums, and again according to the information I have, which was gleaned from the Maersk Supply website, the Maersk Battler had two work drums and one tow drum, actually making it slightly less suitable than the Maersk Chancellor. In fact any of the Maersk anchor-handlers could have carried out the double tow, particularly since it is likely that all of them carried a spare tow wire which could have been installed on a work drum. Did no-one realise this?

But, as is often the case, much of the process including the risk assessment was developed to validate what was in fact a flawed process, and let’s face it the whole job was based on doing things as cheaply as possible, and once every person with the appropriate levels of expertise had gone there was nothing to stop the disaster taking place."


Is side by side towing something that actually happens? Just curious more than anything. Even with a single drum tandem is possible, although dangerous and a pain. I’ve been on the towing side of the industry now for almost 12 years and I’ve never seen this.


These are the type of posts I (and I’m sure many others) appreciate. You’re very knowledgeable and present great info when you like. Thank you for your insight!


The question to be asked is who made the guy with his finger on the pulse redundant. Who thought that an office junior had the required knowledge and experience to assume his duties. These are the people who should be hung out to dry but they are so often allowed to continue on.
The paper work failed to paper over the cracks in the organisation.


In terms of an analogy to the electrical circuit breaker; if an electrical power system fails in certain specific ways the purpose of the breaker is protect the system, the breaker can be said to have stop work authority.

However in the electrical system, if the breaker fails to trip when a fault occurs it is considered prudent to investigate both why the breaker failed to trip and also the cause of the fault.

If the higher-ups at the office create a bad plan and deliver it to the tug the captain is expected to act as a circuit breaker and call off the show. If that doesn’t happen we could simply blame the captain. But to be prudent we should also learn why the office is creating bad plans.


Always bearing in mind that the circuit breaker never ever gets sacked for doing its job.


Yes, but if the breaker trips to early, if the captain refuses to take on risks the office feels he should, it/he gets replaced.

Also, don’t breakers get replaced after so many cycles?


I only meant that the circuit breaker is immune to office pressure – but I see that if you push the analogy then tying down the handle could be construed as office pressure (though many circuit breakers will trip even if the handle is restrained).


I worked anchor handlers for the better part of 15 years. This is simple PPP…piss poor planning. Towing side-by-side is just dumb. It doesn’t make any sense, and I cannot see any sort of risk assessment process mitigating the likelyhood of such an event in this context. As a suitability surveyor, this would not have passed my survey, I can promise you that much. Risk assessing also has actual impact of a loss. Maybe this impact was so low for the organization, that likelyhood became inconsequencial.
Anchor handlers only have 1 tow drum. Yes, there are some 4 drum reverse waterfall winches with two upper tow drums, but in terms of emergency releasing the tow, only one drum at a time can emergency release in a controlled manner. This is certainly a prerequisite in any case.


The fact that an amazingly stupid plan could slip through Maersk’s systems might indicate that a merely “almost adequate” plan could slip though elsewhere.


I have seen fuses replaced with 4" nails. Works in an emergency but not recommended.


The Maersk Battler had more than ample winch capacity to do any kind of towage and anchor handling. (Details of the winches on board in post no. 30 of this thread)


Then there’s the urban legend about the redneck who replaced a fuse under the dash in his pickup with a 22 bullet and got shot in the nuts when it overheated.


I know that winch very well, every design. From the old WINCON DOS, to the NT, and RT based system designs. My knowledge & post is based upon the operation and design philosophy, not a copy and paste of the specs. Winch capacity does not state operational limitations from a servo flow path design, or emergency back up functionality.


I agree. You hit the nail on the head with the comment on towing using the work drum.
Discussion on the master being the final arbiter in setting up the tow is in this case not true and it was recognised by the the inquiry in spirit at least.
The master of an anchor handler is not accorded the same status as say the master in a reputable shipping company and if the jobs not done then he or she is simply replaced.


Yes the Brattvaag winches use Wincon Control system and to my knowledge that has worked very well.
The Maersk Battler had a Low pressure hydraulic winch with two individual tow drums, which could be used for tandem tows.

Emergency release will by necessity be in sequence, not simultaneously.

PS> Don’t know if that has changed with the new E26 proportional pressure compensated valve.