On 29 October 2017, the bulk carrier MS Glory Amsterdam ran aground 1.6 nautical miles north of the island of Langeoog. There has been public incomprehension about the fact that this ship was able to drift from its anchor position in the deep water roadstead in the German Bight to the beach off the island of Langeoog within twelve hours without an emergency tow with the motor tug Nordic being successful at the instigation of the Havariekommando.
The author has analysed the course of the unsuccessful assistance by the motor tug Nordic in his capacity as a publicly appointed and sworn expert for shipbuilding and comes to the following conclusion.
This accident was classified as a serious marine casualty by the Federal Bureau of Maritime Casualty Investigation (BSU) in investigation report 408/17 dated 6 March 2019.
In this 192-page investigation report, the BSU comes to the following conclusion: "Glory Amsterdam broke free from her anchorage in the morning of 29 October 2017 during a gale and drifted through the German Bight for 12 hours until she ran aground on a sandbank off Langeoog in the evening."
One of the reasons for this is said to be
- a stressed Chinese captain
- linguistic misunderstandings
- Lack of seamanship skills
- Emergency tug Nordic not clearly recognised
- Boarding Team (Emergency Assistance Team) was unable to be
Nordic can be wiped off - Drive power too low (9,326 kW)
The author comments on this as follows: From the point of view of a shipping expert, there are - in simplified terms - two decisive events for the stranding of the Glory Amsterdam off Langeoog:
- The anchoring did not hold, so that the Glory Amsterdam
is distributed. - The emergency tow by the Nordic failed after 46 minutes
due to breakage of a bollard tube from the double bollard.
If only one of these events had not taken place, the Glory Amsterdam not stranded.
According to the classification regulations of Germanischer Lloyd (now DNV-GL), the following is pointed out with regard to anchor equipment:
"The equipment is intended for anchoring in harbours or in sheltered waters. The equipment is not designed to anchor a vessel in heavy weather on an unprotected coast or to stop a moving or drifting vessel."
The design of the anchor equipment (anchor weight, chain length, chain diameter, breaking strength of the anchor chain) is determined according to an equipment coefficient. The formula for this is based on the assumption that the current speed of the water is a maximum of 2.5 metres per second and the wind speed is a maximum of 25 metres per second (approximately wind force 10 Beaufort).
According to the DWD's weather map, at around 06:00 UTC on 29 October in the anchorage area of the Glory Amsterdam a wind force of 9 Beaufort and a wave height of 8.00 metres.
As the ship was anchored in ballast without cargo, there was a large area exposed to the wind, which in the author's opinion led to the loss of the anchors.
To make matters worse, two anchors with different chain lengths were anchored at the same time (German Bundestag printed matter 19/1639 of 13 April 2018. Port anchor: 4 x 27.50 = 110.00 metres; starboard anchor: 9 x 27.50 = 247.50 metres). The ship then swings around the shorter anchor chain (110.00 metres) when the tidal current changes, causing the shorter anchor chain to break due to the sole load. If the ship is then drifting, the longer chain length (247.50 metres) will also break due to the kinetic energy.
When, after several failed attempts, a towing connection could be established by the Nordic, this was lost again after 46 minutes when a tube of the double bollard broke off. The load was therefore borderline, because at least the single bollard tube held for 46 minutes.
According to the author's findings, the towline was therefore only used on one bollard tube. If both bollard tubes had been used, the load on the bollard tube would have been halved. Presumably, the emergency tow would then have been successful.
When the Nordic motorised tug moves in a swell, it generates a very large amount of kinetic energy when it "falls into the line". The available maximum bollard pull, i.e. the towing force of the motor tug, is 200.00 tonnes. In rough seas, the tug is not able to reduce the towing force. With a relatively short towline, the kinetic energy of the Nordic displacing 3,600 tonnes can amount to a multiple of the maximum bollard pull. The towline - or in this case the bollard tube - breaks out of the bollard bank.
For this reason, overseas towing operations are carried out on very long towlines of around 1,000 - 2,000 metres in length due to the kinetic energy in rough seas. The slack towline absorbs the kinetic energy of the motorised tug and the towline in rough seas.
With wind force 9 and a wave height of eight metres, the freighter drifted from the deep-water roadstead in the German Bight to Langeoog. (Image: Havariekommando)
In lectures, the author has explained kinetic energy with the following experiment: A parcel tape is supposed to represent the drag line. With the strength of both hands, it is not possible to tear this parcel tape. If you tie a brick to both ends and pull again with both hands, you are also unable to tear the parcel tape. However, if you move the bricks against each other very quickly, the parcel tape tears easily, just like the too-short towline in the swell between the Nordic motor tug and MS Glory Amsterdam.
This effect is of course also dependent on the weight of the brick, which symbolises the motorised tug. If the brick is reduced to a quarter of its weight, for example, which corresponds to a smaller motorised tug of 800 tonnes, it is no longer possible to tear the parcel conveyor (towline) when moving quickly. The smaller mass is therefore decisive. This simplified illustration with bricks helps to understand the kinetic energy that led to the failed towing attempt.
Another point of the investigation concerns the boarding team. At around 11:20 a.m., an attempt was made to call the boarding team on board the Glory Amsterdam was to be taken off the Nordic with a federal police helicopter. However, this was cancelled at around 11:50 a.m. due to the poor weather conditions.
The author is familiar with this process, as he has often been winched off by Wiking Helicopter Service for the purpose of expertises on ships in the German Bight. He therefore understands that it is not possible to winch off the Nordic when the waves are around 8 metres high and the tug is moving.
In the author's opinion, the Nordic should have been moved to a calmer sea area, such as the Jade, in order to winch up the boarding team there in better sea conditions.
Instead, a Federal Police helicopter did not arrive until around five hours later with another boarding team. Glory Amsterdam and set it down on the main deck at around 16:26. But that was too late, because at 18:00 the Glory Amsterdam off the island of Langeoog.
It remains incomprehensible to the author that civilian helicopter companies with extensive experience in winching up and down were not called upon for the mission.
The Wiking company is deployed almost daily to drop off or pick up pilots and other personnel on board ships and oil rigs, especially in bad weather conditions.
In the opinion of the author
- was the anchoring of the Glory Amsterdam in unprotected coastal areas during gale-force winds.
- the boarding team would have had to be ferried from land by helicopter in good time.
- the mooring of the towline to only one tube of the double bollard did not correspond to professional seamanship.
- the bollard pull of the motorised tug could not be adjusted to a lower force due to the heavy swell.
- an emergency tow should only have been carried out on a very long and slack towline due to the high kinetic energy (falling into the line).
Why the Glory Amsterdam The author is unable to understand why the vessel did not haul in the anchor chains and leave the deep water roadstead under her own power. In any case, the BSU's investigation report indicates that the propulsion engine and steering gear were reportedly fully operational.
Author: Dieter Becker
English 
German
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