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What precautions and preparations can ports take to weather the storm, asks John Bensalhia

'Tis the season to be jolly, says the rhyme. The real world regrettably brings less cheer. The Winter season may contain holidays, parties and the occasional hangover, but these days it brings an unwanted guest: bad weather.

It's inevitable that grim weather warnings rear their heads in winter. Whether it's snow, wind, ice or rain, the forecasts make particularly bleak reading. Take last year's stormy weather in the northern Hemisphere which left a trail of havoc in its path. On 23 rd and 24 th December 2013, many UK areas were left battered by storms. The Met Office reported that areas of Southern England and Wales were affected by rain levels which were around two thirds or more of the average rainfall amount in December.

Of course, bad weather doesn't keep to a schedule. Even a supposed hot summer's day can give way to torrential downpours. For ports and harbours, adverse weather (whatever the season) brings a whole host of problems. As Jogchum Beetsma, MetraWeather's business development manager explains, poor weather conditions impact upon ports in many ways.

“Hurricanes, typhoons and other high wind and swell situations and adverse weather have negative impact on vessel and staff safety, fuel consumption and TOA”; berthed ships can be affected by rainfall, swell and wind, and tidal conditions; “the wind can blow rail-mounted cranes along their track mount, dislodge containers from crane mounts and topple mobile crane systems, while lightning is a risk to all outdoor assets and staff”; and wind can cause serious dust management and spillage, he says.

BMT Argoss' David Hurdle, head of vessel dynamics, and Robin Stephens, Metocean group manager, add that a key problem is that of wave excitation within the port and the effects on vessel motion. “This is important for manoeuvrability, berthing, loading and offloading and also mooring line loadings. The propagation of long period ocean swell into harbour basins can be problematic. Additionally, in some locations, seiching and the occurrence of very long period infra-gravity waves can cause large ship motions with corresponding high loading in some mooring lines.”





Dealing with unknowns

One of the chief issues is that adverse weather is an unknown quantity. In the days leading up to the onslaught, it's vital to assess the exact scale and power of what's in store. As BMT Argoss' Mr Stephens explains, there are different scenarios that can adversely affect ports: “Having reliable advanced warning of approaching adverse and limiting environmental conditions is extremely important in informing appropriate operational decision-making. An accurate forecast will allow correct and safe advanced decision-making.

"A ‘false warning’ will bring about unnecessary precautionary actions which will probably have financial consequences. However, the worst scenario is generally a ‘miss’ where the forecast fails to anticipate forthcoming adverse conditions. In this case, precautionary measures will not be taken in advance which may result in safety issues and/or damage to vessels and port facilities.”

A regular word during bad weather spells is the one that nobody wants to hear: delay. Delays mean traffic jams, endless confusion, and passengers packed in like sardines on slow-running trains. But the most damning impact is that delays prove costly. When it comes to ports and harbours, delays mean bad news financially.

Mr Hurdle comments: “Bad weather can cause delays in port arrivals and departures, can slow down operations at berths giving further delays or even cause ships to leave the berth completely due to the risk of breaking mooring lines. Quick estimates based on the costs of port infrastructure (the development of the Maasvlakte 2 extension to the Port of Rotterdam was estimated to cost E3bn) show that delay costs associated with the berth are likely to be measured in tens of thousands of Euros a day rather than thousands. The costs for the delay of the ship are likely to be of the same order of magnitude.”





On alert

But with the forces of nature throwing everything they've got at daily operations, ports can at least do their best to ensure that they are fully alerted and protected. With respect to alert procedures and systems, MetraWeather's Mr Beetsma says that each port will be different, depending on specific operations. “Some have visible and audible alerts when certain observed wind strengths are met. Ports are generally very well catered for when it comes to observing equipment. MetraWeather takes advantage of these observation networks by feeding the locally observed information back into their forecasting processes to further improve the quality of the output. Wind, swells, tides are monitored in real time at most ports. Alerts are often linked to these devices.”

Mr Stephens adds that there are a number of systems that can be utilised. These include well-developed underkeel clearance advisory systems, real-time monitoring of water levels, appropriately sited and well-maintained real-time anemometers for operational assessment of wind conditions, and wave measuring devices such as a wave buoy, subsea acoustic Doppler sensor or permanent wave radar system.

“It is clear that more accurate and more sophisticated information will lead to the fewer assumptions being needed. This should give both higher safety levels and less conservative guidelines. An important qualification to this is that any reduction in conservatism must be coupled with thorough analysis of the reliability of predictions. This is not necessarily straightforward: for example, it is easy to assess error in wave height prediction but how to quantify error in the prediction of wave spectra requires careful consideration.”

There are many precautions that can be taken in advance of approaching bad weather. Mr Beetsma says that these include reduced container stack heights, locked down cranes, the security of loose material and assets, refusal of harbour entry and exit, and ensuring that stevedoring activities don’t clash with onset of inclement weather.

“Precautionary measures will depend upon the nature of anticipated adverse conditions,” explains Robin Stephens. “In the case of forecast periods of insufficient underkeel clearance, the delays can be minimised by giving priority to those ships in the windows available to them. Where this can be forecast sufficiently in advance, ships may be able to speed up or slow down allowing a balance to be made between fuel costs and delay costs. However, it has to be mentioned that contractual issues sometimes make it difficult to achieve the optimal balance.”





Berth safety

Mr Hurdle adds that the safety of ships at berth should also be closely monitored in advance: “In the case of expected bad weather an assessment should be made of the safety of the ship staying at berth. If there is a possibility that it could be unsafe for the ship to remain at berth, safe windows for departure should be assessed. Otherwise, the assistance of boatmen should be called in to ensure the mooring lines are optimally set and stand-by tug assistance should be considered. It is generally safer to weather storms on open sea than at an inadequately sheltered berth.”

Managing the impact of adverse weather is a crucial aspect of port uptime, which is of major economic importance for all ports. As Mr Stephens explains, developing and existing facilities must take action to ensure that they maintain maximum safety and efficiency in the face of poor weather conditions: “For the development of a new facility, it is possible, and extremely important, to consider all aspects of weather-related risk to port operations. Where possible, intelligent design and development of strong operational procedures will achieve a balance between high utilisation and safety.

“For existing facilities, operational optimisation requires detailed understanding of the behaviour of the port basin and the vessels that use it under a wide range of adverse environmental conditions. Furthermore, it is important to understand the physical processes and combinations thereof that limit various operations.”