Owners and operators of container ships can prevent high-cost cargo losses through better use of ocean and meteorological information, said a panel of experts during Riviera Maritime Media’s Weather routeing: minimising the risk of containers overboard webinar
Experts and webinar attendees agreed weather routeing, combined with ocean data, can prevent container ships from risking cargo losses. This webinar was held on 2 September during Riviera’s Container Ship Tech & Ops Webinar Week.
The panel featured B2B7CS founder and chief executive Henry Chen, Wärtsilä deputy general manager of intellectual systems Alexander Ozersky, Container Overboard System (COBS) founder Carlos Freire, and Unikie director for business development and ecosystems Jouni Salo.
Weather routeing is one of many tools available to container shipping companies to minimise the risk of cargo loss. Mr Chen said digital twins, artificial intelligence (AI), ship design, analytical software, ship motion prediction and monitoring will contribute to cutting the risks.
“Given the right tools, the future of weather routeing as a decision support service can minimise container losses while reducing fuel consumption and enable on-time arrival,” he said.
Container ship operators, owners and managers can learn from the lessons learned from previous maritime accidents involving container stacks shifting, with containers lost into the world’s oceans.
Between October 2020 and March 2021, 3,080 containers were lost in seven incidents in the Pacific Ocean. In an analysis of these and other container ship accidents, Mr Chen concluded, “most incidents occurred at night and crew only found the extent of damage caused by excessive roll or boarding waves the next morning”.
Sea conditions were severe with up to 6-7 m significant wave heights, but these ships had experienced worse weather before.
“Most likely cause of the damage was large roll angles and accelerations due to synchronous or parametric roll resonance, resulting in lashing failures,” said Mr Chen.
Severe motions can also cause propeller racing, tripping the engine and loss of power.
“For these maritime accidents, weather routeing service providers and onboard software were not able to predict such risks, re-route the ship or advise the captain,” said Mr Chen. “Crew were not trained to make tactical manoeuvres to reduce the motions when resonance started to occur.”
In response to these findings, Mr Chen suggested shipowners digitalise operations, use shore-side decision support centres and improve crew training. In addition, reducing the crew’s workload by replacing manual reporting tasks with automated, or AI monitoring systems and eliminating silos with competing performance indicators in ship-management metrics would also improve operations.
He also advised ship operators to work with weather routeing services for the latest forecast of storm movements, embrace digitalisation, support safety cultures with continual online training courses in navigation and deploy sensors on ultra-large container ships.
Mr Chen called on weather routeing companies to consider new technologies such as digital twins to accurately predict ship performance using the latest wind, wave and current forecasts.
“True voyage optimisation needs to use seakeeping and propulsion models,” he said. “The ship seakeeping model should be able to predict motions, deck submergence, and propeller emergence for the specified draughts.”
Weather routeing should also incorporate forecasts to predict the probability of ships exceeding their safety envelope and quantifying the uncertainties of fuel consumption and arrival time for better route selection.
The webinar attendees were asked what their top objectives are when engaging weather routeing services. Half of respondents said it was to avoid bad weather and ensure ship safety. Another 33% said it was to protect scheduled arrival times and 17% thought it was to reduce fuel consumption and carbon footprint. None voted for using weather routeing to ’check the box’ for insurance purposes.
In another poll, the audience were asked whether their weather routeing service provider, or onboard software, predicts ship motion along the intended route with forecast weather and actual ship loading condition. 47% said it only shows dangerous zones according to the IMO Circular 1228, while 44% said it offers advice on route changes to avoid bad weather, with the rest up to the ship master and 9% said it was not part of the service offering or features.
Wärtsilä’s Mr Ozersky said weather routeing should be one of the layers of defence to prevent maritime accidents with ship operators using weather routeing before, during and after voyages to minimise the risk of container losses.
“All voyages start with the plan and container loading,” he explained. “Then there is the execution, with continuous communications and real-time replanning, post-voyage analysis and long-term actions, such as training and changing company policies.”
Communicating with onboard teams during these operations will help to learn lessons, improve safety and ship performance.
“In each stage, weather routeing can be applied,” said Mr Ozersky. “There are a lot of stakeholders and all should be sharing information and data.”
He spoke about the anatomy of incidents involving issues, errors or failures in training, tools, policies, procedures and operations. Each element can be tackled to minimise risks.
“We can look at the layers of defence and support fleet operations with tools such as weather routeing, automated warnings, tools to support real-time operations and reduce pressure on bridge teams,” said Mr Ozersky.
Wärtsilä provides many of these defensive layers in its Fleet Optimisation Solution (FOS), including weather routeing, voyage optimisation, tracking and awareness systems and simulation modules.
The importance of providing weather routeing and sea condition information in real time was highlighted in a question to webinar delegates. When asked whether the average bridge officer can identify the dangerous course and speed that may lead to container loss in rough seas, half of the audience disagreed and 16% strongly disagreed. Only 21% agreed and 13% strongly agreed.
Attendees were then asked if their ship masters follow IMO guidance to avoid dangerous synchronous and parametric roll. 40% said sometimes and only in bad weather and 50% voted for the need for real-time data, such as swell period and direction, for it to be useful. Just 10% said no proper training was given.
In his presentation, Mr Freire highlighted the key reasons behind container losses with particular reference to the accident involving ultra-large container ship (ULCS) MSC Zoe in the North Sea in January 2019.
He said ships sailing in adverse weather were responsible for half of cargo loss claims and some 80% of the costs.
“Extreme motions, such as parametric rolling and synchronous roll resonance phenomena have caused several serious accidents to container ships,” Mr Freire said.
Parametric rolling involves large spontaneous rolling motions occurring in head or stern seas. “It has to do with the dynamics of the ship and waves, as well as the vessel’s wave encounter period,” explained Mr Freire.
A vessel’s roll angle can increase from comfortable rolling motions to over 30º in only a few cycles causing excessive acceleration on the container stacks.
“Synchronous rolling is caused by the ship’s rolling period becoming synchronous with the wave period,” he continued. “The waves may then cause resonance, meaning the ship may lose control over the roll angels as the action of the wave rolls the vessel increasingly over.”
An investigation by research institutes Deltares and MARIN for the Dutch Safety Board into MSC Zoe’s accident off the Dutch Wadden Islands discovered the reasons for the loss of 342 containers during a storm. The ULCS was impacted by parametric rolling, shocks and vibrations. It has a wide beam of 60 m, which makes ULCSs stable, as when a force is applied to them, they will return to their upright equilibrium position relatively quickly.
“This results in a short natural period during which the ship starts to roll as it is brought into motion by an external force,” Mr Freire explained. “For the present generation of ULCSs, this natural period can be between 15 and 20 seconds, close to the wave periods that occur above the Wadden Islands in such north-westerly storms.”
As a result, roll resonance may occur, causing heeling angles of 15-20º. Such extreme roll amplitudes combined with high ship stability can cause large accelerations and forces being applied to the containers that can exceed safe design values.
“In these beam waves, ships do not only roll from side to side, but also heave up and down many vertical metres,” Mr Freire explained in his presentation notes.
With a draught of around 12 m in a water depth of only 21 m, there is very limited under-keel clearance between the ship and the seabed. In this case, less than 10 m. As a result of the combined rolling and heaving, wide and deep ULCSs can touch the seabed.
When this happens, shocks and vibrations can occur in the ship, containers and lashings. This was experienced in the MSC Zoe incident as the ULCS’ hull encountered green-wave impacts.
This investigation into the MSC Zoe accident is a rare event, according to the webinar attendees. In a poll question, they were asked how many near-miss incidents related to strong waves and potential container loss are reported and investigated? 67% of those responding thought it was just 25% of these near misses, with 19% saying it is 50% and 14% thinking it was none of them.
Unikie’s Mr Salo said container ship accidents, such as MSC Zoe, demonstrate much more needs to be done to improve ocean environmental forecasting.
“Wave forecasts are not good enough and we need more information on sea states, wave periods and the direction of waves,” he said.
Using better information, ship captains and operators can “recalculate voyages to see how a ship will attack the sea states”. Mr Salo said this was a “call to action” for the shipping industry to provide more information and advice to bridge teams.
“With weather routeing, there needs to be more transparency and availability,” said Mr Salo. “We need to use tools for better decisions and information exchange.”
Sharing data is a key issue in the shipping industry. In a poll of the webinar audience, 52% agreed bridge teams and offices have equal visibility of routeing information and risks, when discussing voyage re-planning. 24% of those responding strongly agreed, while 18% disagreed and 6% strongly disagreed.
In another poll, webinar delegates were asked how many voyage optimisation tasks they automate. To this, 26% said none, 43% voted for 1-4 and 31% thought it was 5-9.
They were also asked if port information was easily available through their operations in a timely manner, 38% disagreed, 33% agreed and 29% strongly agreed.
On Riviera’s Weather routeing: minimising the risk of containers overboard webinar panel were (left to right)
Wärtsilä deputy general manager of intellectual systems Alexander Ozersky, B2B7CS founder and chief executive Henry Chen, Unikie director for business development and ecosystems Jouni Salo and Container Overboard System (COBS) founder Carlos Freire