Tugboat

A tugboat is a small, powerful and strongly-built marine vessel, designed to manoeuvre large ocean-going ships to be able to dock at port. They are also used to tow barges, disabled ships, or other equipment.

Tugboats are usually powered by large diesel engines, which typically provide the ship with 750 - 3000 horsepower. Most tugboats are less than 40 metres long, but they can be as large as 70 metres.

The hull of a tugboat is resilient, and is often padded with tyres to protect in from collision damage.

The powerful engine, and tough construction, make conversion into a type of ice breaker[?] easy.