What is a tug?

A tugboat is a multi-purpose work vessel specially used to tow other ships or floating structures. It is widely used in inland shipping, port work, marine rescue, and marine development.

Tugboats are large ships that provide power for other ships. In addition to towing ocean-going ships in inland rivers or harbors, they are also responsible for rescuing ships in distress. Tugboats are characterized by their small hulls, excellent maneuverability, and high power.

The tugboat is equipped with special towing equipment including tow hooks, tow columns, cable winches and other special towing equipment.

The ability of a tugboat is generally measured by the power and towing force of the main engine.

The more power it has, the greater its towing capabilities will be.

Therefore, the tugboat is a veritable "locomotive" for water transportation.

The types of tugboats are divided according to the navigation area, and of course are related to their power.

Those with high power are generally ocean tugs and coastal tugs, while those with low power are inland river tugs and port tugs, etc.

An ocean tug is also called an ocean rescue tug. It must have good navigation performance and can go to sea under harsh conditions. It must also have a high speed, generally between 17 and 20 knots, and some as high as 22 knots, so that it can

It can rush to the accident waters as soon as possible to complete the rescue mission and reduce losses and casualties; it also has good stability and strong wind resistance, and has multi-functional rescue means.

Since the ocean rescue tug performs long-range rescue and towing tasks, it must have good endurance, generally up to 15,000 to 20,000 nautical miles.

Therefore, its fuel loading capacity can reach more than 1/3 of its full displacement.

In recent years, large-scale ocean development has suddenly emerged, adding a new member to the ship fleet - ocean exploration platforms and offshore oil drilling platforms.

The platform itself has no self-propelled capability, so ocean rescue tugs or coastal tugs are duty-bound to undertake the task of transporting the platform from one well location to another.

During towing, due to the high center of gravity of the platform, it is easy to become unstable and tip over. Therefore, it is very important to ensure the stability of the platform during shifting and towing.

Under normal circumstances, the displacement of a drilling platform requires two tandem tows or three or even multiple tugboats.

On the coastal and inland river transportation lines, there are a large number of coastal tugs and inland river tugs working day and night. For example, my country has finalized the production of coastal 660 kilowatt tugs, coastal 294 kilowatt tugs, and Yangtze River 294 kilowatt tugs.

They are water "locomotives", dragging a series of barges similar to train carriages, forming a long water queue active between ports.

The barges towed by tugboats include cargo barges, oil barges, sand ore barges, coal barges, livestock barges, tank barges, etc. They are responsible for heavy transportation tasks.

In various ports along the coast, various types of ships come and go. From time to time, ships leave the dock or turn around in the port.

Due to the frequent traffic of ships in the port and the tight shoreline of the dock, it is difficult for large ships to leave the dock and turn around by relying on their own power. However, harbor tugboats with good maneuverability and stable performance can tow them to turn around or enter and leave the port, assisting large ships to dock and leave.

Wharf, tow ships in and out of the dock, tow engineering ships and fleets to engage in formation, life-saving, fire-fighting and other work.

There are two problems with tugboats in towing transportation: First, the tugboat is in front and the barge is behind, and the rapids produced by the tugboat's propeller hit the barge behind, which increases the resistance of the barge; second, during the towing operation, each ship

Barges must be equipped with boats, and each boat needs to be equipped with living cabins and a set of operating equipment.

In this way, the auxiliary equipment on the barge is relatively complex, so the cost and daily operating expenses are relatively high.

In order to overcome the above shortcomings and reduce the cost of barges, people have long had the idea of ??changing tug boats into push boats.

Pushing transportation has obvious advantages over towing transportation: First, under the condition of the same size of the fleet, the resistance can be reduced, so the speed can be increased by 10% to 15%.

In this way, the transportation volume can be increased and the unit transportation cost can be reduced.

Second, there are no crew members on the barge, so the fleet's labor productivity can be greatly improved.

Third, there is no superstructure and rudder device on the barge. The structure is simple, saves materials, and is easy to process. It can reduce the cost by about 10%.

Compared with the tugboat, the push ship has two obvious different characteristics: First, the push ship is equipped with a push frame at the bow end of the ship.

Second, because the pushing ship is behind the barge, which affects the driving vision, the driving cab is often raised by 1 to 2 floors.

The main reasons for the development of offshore push transport abroad are the low cost of shipbuilding and the saving of crew wages.

Due to these two reasons, the unit transportation cost of the push fleet is generally about 25% lower than that of cargo ships.

However, compared with self-propelled cargo ships, maritime push transportation also has weaknesses such as low speed and poor resistance to wind and waves. It is generally suitable for routes with abundant cargo supplies and stable cargo batches, and its application is not as extensive as inland river push transportation.

Offshore push vessels are under development.

At present, pusher ship sets are tending to become larger and push wheels and connecting devices are standardized.

The barges used for offshore pushing abroad generally reach 40,000 tons, the large oil barges being designed and manufactured reach 100,000 tons, and the power of the pushers reaches 16,200 kilowatts.

Diversification of uses is another feature in the development of tugs and pushers.