Mavis, the Little Tugboat, Saves the Bridge

A part of the Little Tugboat series - true stories of the
tug's heroics in a children's series which show random
tugboat adventures through the eyes of imaginary tugboat
characters and their captains.
Contained on every book:
Tugboats are the unsung heroes of our waterways - they
move other boats and structures through our waterways,
such as ships into harbours and small and narrow canals,
oil platforms, bridge pylons, and undersea tunnels into
place. Some act as icebreakers or salvage boats. Tug
boats are the fire engines of the water. No matter what
a tug's specific job is, they are strong, nimble, and often
overlooked.