Harbour tugs are the most typical of the tugboats that people recognise. They’re used worldwide to move ships in and out of berth and to move industrial barges around waterfront complexes. Their job has remained the same but their design and engineering has changed much over the decades. Harbour tugs originally evolved from paddle wheelers into the conventional tug known by all, and evolved further into Ship Docking Modules and tractors.
River tugs (also known as towboats or push boats) are designed as large squared-off vessels with flat bows for connecting with the rectangular stern of barges. They are large and powerful, most commonly seen on the big rivers of the world and are capable of pushing huge fleets of barges that are can be lashed together into "tows". Some tows can be up to 1,000ft long and 200ft wide. In inland waters, smaller push boats may be seen managing only a few barges. Despite their size, they are designed to push their tow rather than tow from the stern.

Wonderful! Must pop into Woolies to get a few. Bath time gets boring with only a submarine to play with.

HeHe