Preventing Ship Allisions of Bridges
Tugboats (Tugs)
Tugboats (also called tugs) are small ships with large engines. They are designed to guide a large or heavy ship, by pushing or towing the other ship.
Figure 1:
Tugboat (left), in Japan, attached to a barge being loaded
with sand.
The tug will push the barge to a low pier
that will be filled with the sand.
[Kashima]
Figure 2:
Tugboats in Japan guiding a crane barge that
is carrying a steel-sided low pier it will place
in the water to be filled with sand from the
barge above.
[Kashima]
Port Safety
Tugboats are an integral part of port safety, assuring large ships are maneuvered correctly.
Figure 3:
Tugboats docking a 366 meter long cargo ship at Tema Port,
Ghana.
[Tema]
Figure 4:
Tugboats docking a 225 m LPG Tanker in Pennsylvania.
The Commodore Barry Bridge is in the background.
[CharlesHomler]
Figure 5:
Tugboats undocking a ship in Europe.
[KeesTorn]
Figure 6:
One of the tugboats from above.
[KeesTorn]
Figure 7:
Tugboat pushing a barge under a drawbridge in New York.
The tug is taller than the barge, requiring the drawbridge to open.
[Wiki]
In the drawbridge photograph, notice the strong box shape of the bridge piers and girders, joined with multidimensional contact interface.