noun
push boat; pusher craft; towboat
A vessel designed to push barges or other craft, typically in inland waterways or harbors.
この港では押し船が貨物のはしけを押して運んでいる。
In this port, push boats are moving cargo barges.
タグボート (tugboat) typically pulls vessels, while 押し船 pushes them.
Compound of 押し (pushing) + 船 (boat).