Make Weather Data Work For You: Nigel Allen

December 26th, 2013 by JCB
Posted in Articles, Technical and Training | No Comments »

Following on from Jonathon Pearce’s DUKC feature ,this account serves to highlight the importance of environmental factors in passage planning. (Ed)

Consider the following scenario between a shore side Vessel Traffic System (VTS) operator and pilot:

VTS: The ship on your berth has gone back half an hour and the two tugs from that vessel will come to you.

Pilot: My tidal window closes at 0950 hrs and the weather forecast is not looking very helpful either!

VTS: OK, the last low water was 0.2m above prediction and the current trend is 0.25m above prediction and the barometer is still dropping. If we skip the swing and go straight alongside port side to, how does that extend your tidal window?

Pilot: I’ll get back to you.

This conversation will be familiar to pilots and masters alike. Operational changes that affect planned shipping movements can be disruptive and costly; accidents even more so.

Ships are increasing in size but many ports are not and, as a consequence, the margins for error have increased. Typically, a large container ship can cost more than $100M, the value of the cargo many times more, and daily running costs of these vessels are huge, with delays creating complications and rescheduling likely to be expensive.

Everybody in the chain is under pressure to perform and with such expensive assets sailing in and out of your port, it is essential to offer the best possible service you can. As the above scenario highlights, hydrological and meteorological  information can impact operations during a vessel’s approach to port, manoeuvring alongside and even its cargo handling operations.

A ship’s arrival is planned days in advance and it is in the interests of everybody involved that things run to schedule, at the sharp end, decisions need to be made that produce a safe outcome. Weather is one of the most changeable factors and so it is important that this information is up-to-date and used to its best advantage.

The methods of providing reliable and accurate hydrological/meteorological information based on both actual and predicted conditions have improved and can be more easily shared with relevant parties. It was for this reason that, in December last year, a PIANC (The World Association for Waterborne Transport Infrastructure) working group published its report on the Use of Hydro/Meteo Information for Port Access and Operations. The group of 13 experts met ten times over the course of four years and were asked to pay special attention to access windows for channels subject to tidal restrictions.

Time is one of the most important factors when considering an up-to-date forecasting system. With the new and more robust monitoring and data communications techniques that are available today, a port should aim to develop a system that can make a forecast and deliver that information to the end users in real time. In this way weather conditions can be pre-empted and operations adjusted to suit these conditions.

Each port has its own specific conditions but in all cases accurate, timely and reliable data is of crucial importance. Hydro/meteo information across the globe is ample and easily obtainable from meteorological institutes running a network of monitoring locations.

In most cases, however, a port will need more specific information in addition to this, so it may be necessary to add a dedicated monitoring location in the vicinity of the port. Further port specific data, such as waves and currents, may also be needed and a dedicated monitoring programme would be required, information from which would be input into the forecast system.

Bringing together all these forms of data from the various sources, is the first step towards a comprehensive picture of the hydro and meteo conditions in any port. A quick search on the internet will reveal the existence of an array of easy-to-understand port websites displaying hydro/meteo information. Take Port of Rotterdam’s Internet Amethyst website, for example, which is periodically fed with data from the monitoring networks in the port area. I can even download free weather information on my iPhone that can be superimposed onto my chart data using an app called Pocketgrib. There is now a level of information out there that simply wasn’t available before. And if I can get up-to-date-information on my iPhone, think of the possibilities for a port.

The relative costs of setting up or updating a forecasting system in a port, compared with the value of the assets at risk, is quite small but vital if a port wants to remain competitive in terms of being efficient and effective.

So, back to our delayed ship:

Pilot: With the tide running 0.25m over prediction that extends my tidal window by 18 minutes and as we‘re not swinging, that reduces the time required to berth by 15 minutes, so despite the delayed vessel sailing we can still safely proceed. The master has also advised that he can move some ballast around which will reduce the maximum draught by 20cm, which will further increase our safety margin by extending my tidal window by another 15 minutes. Further, looking at various ‘live’ websites, it would appear that the wind will now shift to the northwest a little earlier than originally expected, which will also be helpful whilst berthing.

VTS: That’s great. I’ll advise the terminal that you’ll now berth port side alongside, so they can make the necessary cargo adjustments. The two tugs ordered have just called in and are now confirmed as available. The pass with the outbound ship is scheduled for 0835hrs at the junction buoy. I’ve just spoken to the meteorological centre and they confirm a wind shift to the northwest around 0900hrs. Presently we have 250 degrees at 27kt, gusting to 33kt, trend steady.

Nigel Allen (Southampton. Retd)

 

Nigel Allen took part in the PIANC (Permanent International Association of Navigation Congresses) working group on behalf of the International Maritime Pilots’ Association (IMPA).

 

The PIANC report is available at: www.pianc.org/technicalreportsbrowseall.php
Price: €90

 

This feature is edited from an article first published in Ports & Harbours magazine and is reproduced here with their kind permission.