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Safer Seas

The Swedish Club Letter 1–2003

Weather Routing

  • a way to Safer Sea passages

ony Schröder

CLAIMS EXECUTIVE Claims & Legal Support Department The Swedish Club, Göteborg

  • 

    On November 24th 1997 a container vessel

broke in two pieces near the Azores. The crew of 34 were all safely rescued. The two pieces of the vessel drifted for a while before the forward part eventually sunk. The aft part was towed into shelter and some of the cargo was saved. The intensive storm on this fateful day made for a significant1 wave height of 16 metres near the Azores. The storm had been predicted a good five to seven days in advance. Vessels using rout- ing service were all routed far off the critical area with the severest weather. The container vessel in question was the only ship that ran straight into the storm. They did not use weather rout- ing. The incident still has unresolved issues and litigations have been started in both the U.K. and the U.S., sparking claims of about USD 130 million.

Pre-voyage planning The use of weather forecasts when planning ocean crossings, weather routing, as a means of preventing and minimising the effect that heavy weather can have on the vessel, and per- haps more importantly, the cargo, has been in use since the early 1960s. The U.S., the U.K., Denmark and Sweden, each country creating their own standards on availability and useful- ness, initially developed the concept of weather routing. The forecasts of the oceans, however, were not good enough and this restrained the launch of weather routing. The launch was also restrained by the fact that communications systems were nowhere near as practical and user-friendly as they are now. Those were the main reasons why weather routing did not have its practical breakthrough until the late 1970s to early 1980s. This is when the Swedish Mete- orological and Hydrological institute (SMHI), a governmental agency, created a branch called SMHI Weather Routing, for the purpose of specifically aiding the shipping industry with a good value2, yet reliable, service for the master of a ship to better predict the voyage to come, i.e. pre-voyage planning. This had a significant


impact on the master’s possibilities to foresee what lay ahead, when e.g. crossing the North Atlantic during wintertime. Today, with high speed data transfers and satellite communica- tions, the master on any given ship, at any given spot on the globe, can get instant updates on the weather system affecting him, the crew, the vessel and the cargo. He is also able to get new advice on the present routing in an instant.

Use of weather routing The use of weather routing and forecast services was from the beginning mainly for the use of the shipowners for the safe navigation of their vessels i.e. to try to avoid bad weather, which, as is well known, can damage the cargo. Today, however, these reasons are paralleled by the need for accurate estimated time of arrival (ETA) planning in order for the shipowners to satisfy customers demanding information on where their cargo is, when it will arrive, and where and when it can be picked up. The ever- increasing need for “just-in-time” logistics has forced shipowners to use whatever available. The means to an end being a weather routing service. Another important factor is bunker consumption. Running into severe weather does not just mean that the ETA is lost but also that the bunker consumption will be higher in order to reach the destined port of call. It is not only the shipowners and charterers that directly benefit from the weather routing service. The Swedish Club has benefited fairly regularly from the service that SMHI provides on a global scale, by using weather routing as a platform for decision making in salvage and towage situations.

Tailor-made service Tailor-made weather routing service can be required, on each and every voyage. There is an intrinsic value in avoiding mass production. The approach is to work in close symbiosis with the master of each vessel, from the start of the voyage until the port of call has been reached. This is believed to be essential on the basis that no voyage is quite the same as another. The Swedish routing service uses forecast data from the European joint weather centre, the European Centre of Medium-Range Weather Forecasts (ECMWF), located in Reading, U.K.

They presently have the best numerical models in the world for the calculation of weather, winds, waves and swell and their mutual cor- relation. ECMWF covers the entire globe and their supercomputer is the most complex and most accurate weather computer in the world. It can calculate all the relevant parameters up to ten days ahead for the entire globe. Examples of parameters are air pressure, surface winds, significant and maximum wave heights, swell height, direction and period, sea surface tem- peratures, which is combined with actual data of currents, tropical cyclones/hurricanes, ice and iceberg information and last but not least ship-specific performance calculations.

The main service that weather routing provides is route forecasts and route recom- mendations on ocean crossings, world-wide. These include recommendations and forecasts of wind and sea conditions both in tabular form and in the form of maps. They also include ship-specific performance calculation and ETA planning. A staff of well-educated marine me- teorologists work within the Swedish weather routing. They have substantial experience and in-house know-how of shipping activities and their special needs.

Special Harbour Forecast Two other areas of service provided by SMHI Weather Routing are short distance sailing and Special Harbour Forecast (SHF). On short distance sailing the ETA planning and need for “just-in-time” is even more important as the vessels usually trade to tight timetables. These types of forecasts can save considerable time depending on decisions on lashing and stowage procedures. Ports use the SHF service too, for decisions on how to use tugs and, inter alia, how to perform harbour manoeuvring. These forecasts can be delivered two to three days prior to arrival.

On board route planning system A new service is an on board route planning system, which has been developed between the Swedish weather routing and the Seaware Company (www.seaware.se). Compared with other systems this also contains professional calculations of the sea keeping conditions, such as predictions of the forces on the ship/cargo,


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