Anti-roll system against container loss at sea
During the Shipbuilding, Machinery & Marine technology exhibition, better known as the SMM, it became clear that both MSC and Maersk are in the process of implementing an anti-roll system on their ships. With this, they hope to reduce stability problems, something that can currently still lead to container losses at sea. Both shipping companies are doing this separately to improve safety on their container ships.
MSC has signed a deal with the Norwegian ship classification society DNV for the first hundred Anti-Roll systems and will thus be the first shipping company to use this system. The system will be installed in new-build ships and already existing ships with a capacity of 1,800 to 24,000 TEU. These ships will receive a classification ARCS (Anti-Roll for Containerships) with which they can prove to be extra secure against container loss.
The system is designed to help the captain make risk assessments during severe weather conditions at sea and thus prevent parametric roll and synchronous roll.
In parametric rolling, the ship sails with the waves but stability problems can occur due to very high wind forces. This is because the ship tilts so much that container lashings collapse under the pressure.
When a ship goes crosswise against the waves, this is called synchronised rolling.
The Anti-Roll system is to be built in to the existing Weather Routing System says DNV. The system should help provide an even clearer and simpler picture of potential risks. This is done by linking course data, speed and cargo of the container ship to weather models. This allows the captain to more accurately determine the best route in adverse weather conditions.
Maersk has contracted with Kjaerulf Pedersen a Danish company. This company develops sensors for various industries to measure, for example, temperature, humidity, CO2 and movement.
Maersk and Kjaerulf Pedersen have already developed a sensor together, which has already been tested on four container ships sailing from China to USA since January. So far, the test results are positive and the sensors will also be installed on other ships in the Maersk fleet.
The sensors made by Kjaerulf Pedersen do not provide information to the captain like DNV’s system. The sensors are placed in the bow, midship and stern of the ship and can register around 100 movements per second. This data is then compared with the vessel’s speed, acceleration and direction. Does the system detect that a dangerous situation could arise? Then the system issues a command to the ship’s steering system to change course and thereby circumvent the potentially dangerous situation.
A Parametric roll can happen within 8 wave cycles, each lasting about 4 seconds, and the angle of inclination can double with each roll. This happens so fast that it is almost impossible for a human to detect it. With sensors that get through hundreds of data per second and can immediately send corrections, dangerous situations are avoided before the crew realises it.
It is also eventually planned that the information from the sensors will be stored at a central point so that all ships of the shipping company can make use of the collected information. This will allow dangerous situations to be detected quickly and will greatly improve safety. In the future, the data could help with the loading of ships by making better weight distribution, for example.