A fireboat or fire-float is a specialized watercraft with pumps and nozzles designed for fighting shoreline and shipboard fires. The first fireboats, dating to the late 18th century, were tugboats, retrofitted with firefighting equipment. Older designs derived from tugboats and modern fireboats more closely resembling seafaring ships can both be found in service today. Some departments would give their multi-purpose craft the title of "fireboat" also.

Pyronaut is a specialised form of fireboat known as a fire-float. It was built in 1934 by Charles Hill & Sons Ltd., Albion Dock Bristol, Yard No. 208. Registered number 333833. She is owned by Bristol Museums and based at M Shed in Bristol's Floating Harbour.