The name Tug Boats gives a fair idea about the size and task of the vessel being discussed. These are relatively smaller but very powerful for their size. These are primarily used to tug or pull vessels that cannot move by themselves like disabled ships, oil platforms and barges or those that should not move like a big or loaded ship in a narrow canal or a crowded harbor. In addition to these, tug boats are also used as ice breakers or salvage boats and as they are built with fire fighting guns and monitors, they assist in the fire fighting duties especially at harbors and when required even at sea.
With the developments in the shipping industry the ships began to grow larger than they ever were in the history. It is easy to maneuver them at sea but becomes exceedingly difficult in narrow sea strips and harbors because they can move forward and backwards with ease but usually have problems with sideways movement. This is when the need of tug boats was felt and thus these vessels were introduced to help the larger ships navigate the narrow waters. This came to be known as tug assist and thus the name of the boats.
Most of these boats can also venture out in the ocean but some of them are not that strong like the river tugs. The river tugs are tow boats designed to help out in the rivers and canals. They have a hull design that makes it quite dangerous for these boats to venture into open Ocean.
The tug boats were one of the first to have a steam propulsion engine which in today’s time has been replaced by the diesel engine. An average tug boat has an engine of 680-3400 hp (500-2500 kW) but boats which are larger and venture out into deep waters have engines with a power close to 27200 hp (20000 kW) and a power : tonnage ratio ranging between 2.20-4.50 for large tugs and 4.0-9.5 for harbor tugs. These are extremely high ratio especially considering the ratio of the cargo ships or general ships that varies between 0.35-1.20. Such boats usually have engines which are quite similar to the ones used in railway locomotives but with a notable difference that they mechanically drive the propeller instead of converting the output to electric motor supply.
Since the maneuverability of a tug boat has been one of its assets, all the engine developments over the years have focused on the aspect of improving on it without compromising on the strength and power of the vessel. Thus the transition from the paddle wheels to the propellers. The tug boats have been the topic of many literary works especially children’s works like cartoons. They have provided inspirations to many to create characters that have long lived in the memory of the people and attracted many to study them. The real life boats and their crew are as resolute and lovable as their counterparts in fiction and the cartoons. Looking back, one can easily say that a tug boat is more than just a boat, and an important jigsaw piece in the historical scheme of things about everything related to sea.