Superior St Lawrence

摘要

Dennis Littler traces the maine super highway that allows large ocean-going vessels access to North America's Lake Superior from the Gulf of St Lawrence and the Atlantic Ocean via major lakes, navigable rivers and some impressive man made waterways. Located some 1,100 nautical miles from the Gulf of St Lawrence, the American ports of Duluth and Superior, like the Canadian port of Thunder Bay, once known as Fort William, are all located on Lake Superior and are the western termini for deep sea vessels utilising North America's navigable lakes, rivers and canals. The products trans-shipped at these lakehead termini include iron ore, grain and a limited amount of coal. Shipping heading east out to the Atlantic from these ports has to pass through the open waters of Lake Superior, the largest of the lakes encountered on the route to the open sea. Superior rarely freezes over despite the harsh winter conditions, but its ports are usually ice-bound from December to April, which can limit shipping activity on the lake in the winter months.