A tugboat is a small sturdy and powerful vessel designed to push or tow other vessels and barges
Tenacious
You will see them in every sizable port; smart, businesslike small ships, low in the water and surging out to a large inbound ship. Tugs represent power for pushing and pulling, an engine with just enough hull for adequate buoyancy. Thick fenders for close-quarters work, pushing a big ship alongside the quay against the wind, hauling her off at the end of a towing wire.
An assortment of reptiles and amphibians that might be observed in and around the water. There are many other types as well. Except for a single species of frog, amphibians are absent from the marine environment.