Tugboat and Towboat Types

Modern Ocean Towing Tugs

Above: The Crowley tug Warrior is shown underway amid sheet ice in Alaskan waters. In recent years Crowley has been one of the primary marine towing companies involved in regularly scheduled long distance open water towing with fixed equipment like container barges, operating on established routes.


This category of tugs includes primarily vessels of convention tug hull design with sheer but without raised forecastles, that are equipped with fenders to make them usable in docking operations if needed, but whose primary function is ocean towing along established routes. Crowley Maritime is one of the primary operators of tugs of this type, using them in service from the US East Coast to ports in the Caribbean, and from the US West Coast to destinations in Alaska and elsewhere in the Pacific.

These tugs are generally slightly smaller than traditional seagoing tugs, but have similar range capabilities. They usually are of greater displacement and have much larger fuel capacities than tugs that are used in coastal barge towing between destinations within the United States. In some instances they may operate with notch barges, but in most operations they are used for astern towing. For this use they are equipped with large multiple drum towing winches and are provided with long towing cables.

The typical size range of these tugs is around 140 feet, and the typical machinery installation is 6000 to 8000 horsepower. They are almost invariably twin screw vessels for safety and propulsion system redundancy in long distance open ocean operations. The Crowley Invader class is typical of this type of tug, having 7000 installed horsepower and being used in operations on the East and West coasts.


Above: The tug Intrepid is shown underway towing a pair of large barges astern in San Francisco Bay. This tug is nearly as long as a World War Two Army LT type, and is capable of extended ocean towing operations.


The photos above were provided courtesy of Electro-Motive Diesel.

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