Tugboats are little boats with lots of power
Tugboats help move big ships and barges
Tugboats have big, strong engines
The engine fills most of the space
In a tugboat the engine turns large propellers under the tugboat
These blades push tugboats through the water
Thick ropes called tow lines tie tugboats to ships
The captain steers a tugboat from the pilothouse
Tugboats help move big ships in tight places
Big ships can't turn easily in narrow harbors and rivers
Tugboats also can pull ships
With towlines, tugboats help move ships into harbors
Tugboats turn ships to go back out to sea
Tugboats are small but they are very strong
Tugboats are mighty machines
