maximizing water levels

How can a shipping line whose vessel is leaving Europe know what the depth of the channel will be seven or eight days later?

Environment Canada, the Canadian Hydrographic Service and the Canadian Coast Guard issue each day water level forecasts for the coming weeks. The information is more precise as the date of departure approaches, meaning the shipping line can better determine, for example, the number of containers its vessel can carry.

This calculation method has existed for many years. But today, thanks to electronic navigation and a better understanding of the riverbed, calculations are much more precise, meaning shipping lines can better maximize the channel depth for optimum vessel loading.

Ship design is another major advancement. Standard “Panamax” vessels generally prevail in today’s shipping industry. Panamax is determined by the width of the Panama Canal lock chambers, which are 33.53 metres wide. A Panamax vessel has a maximum width of 32 metres. Ships that are wider than 32 metres are known as post-Panamax vessels. The Panama Canal will be able to accommodate even wider vessels starting in 2014 with the completion of an expansion project that will add 55-metre-wide lock chambers. Capitalizing on the principle that wider vessels can carry more cargo while maintaining the same draft, shipyards are now building the next generation of ships with widths that can vary between 32 and 49 metres.

Applying this same principle to the St. Lawrence, a ship that sails up the river today that is similar in length to a Panamax vessel and can carry 4,200 containers would be able to transport, with an equivalent draft, 5,800 containers, or 16,000 more tonnes of cargo, if its width were 42.5 metres instead of 32 metres. Another way of looking at this is that the effect of the widening of a vessel on its transport capacity is comparable to adding 2.1 metres of draft. The use of such vessels on the river would allow for the transportation of greater volumes of cargo to meet market demand, and would also counteract any eventual decrease in water levels due to global warming.