TUGBOATS

A tugboat is a boat which maneuvers vessels by pushing or towing them.

Mainly used for

• Vessels that should not move themselves ( Eg:Ships in crowded harbor)

• Platforms or vessels that cannot move themselves(Eg: Oil platforms, Barges)

Tugboats are strongly built for their size and some of them even assist in firefighting




Tugboats are mainly classified into 3 types

1.      Seagoing

2.      Harbor tugboats

3.      River tugboats

Seagoing:-

These are the vessels which carry the ships to the sea.These are classified according to the connectivity between the tug and thebarge. The classification is as follows

1.      Notch tug

2.      Integrated tug

3.      Articulated tug & Barge

Notch tug:-

It is tug specially designed to aparticular Barge. The tugboat contains a towing winch at its stern but the specialtyof it is that it has a deep notch at the stern (as deep as 90 ft.). The notchis built in exact shape of tug’s forward hull.  Now the stern of the Barge snugly fits into thenotch present at the stern of the tug and the combination becomes a ship. TheBarge and the tug are firmly attached with the lines. The main advantage isthat it can be moved faster than in normal towing. When the weather conditionsare extreme the lines are let loose so they get separated but it is notgenerally recommended because that will damage the tug and tow. Operating in the notch shields the tug from sea conditions and is themost advantageous position for maneuvering the tow.






Integrated tug:-

The Integrated Tugand Barge (ITB),comprises specially designed vessels that lock together in such a rigid andstrong method as to be certified as such by authorities (classificationsocieties). These units stay combined under virtually any sea conditions andthe "tugs" usually have poor sea keeping designs for navigationwithout their "barges" attached. Vessels in this category are legallyconsidered to be ships rather than tugboats and barges. Navigation lights presentshould follow as required by ships rather than that of a tug and a barge.




Articulated Tug andBarge (ATB):-

ATBs are similar to that of a notch tugs but these utilizemechanical means (pins, clamps etc) to connect to their barges. They remaincoupled all the time. ATB's generally utilize Intercon and Bludworth connectionsystems. The main advantage of ATBs is speed, safety, and cost efficiency. InATBs the tow and barge may roll simultaneously but should pitch separately.






Harbour tugs:

These are used to carry the ships into the harbour or awayfrom the harbour.  The width to lengthratio is higher compared to the seagoing tugs because they need a lower draught. These are also called as Lunch BucketBoats because they are only manned when needed and only at a minimum (captainand deckhand), thus the crew will bring their own lunch with them.






River tugs:

These are often referred to as towboats or push boats.Their hull designs would make open ocean operation dangerous. Their hullsfeature a flat front or bow to line up with the rectangular stern of the barge,often with large pushing knees. They can tow a large fleet of barges