Single screw steam tug, built in 1899 by William Allsup & Son (Preston) for £4,150. Sold in 1927 to Workington Harbour and Dock Board for £2,500
via Flickr http://flic.kr/p/r8sk39
From Flickr: “Preston Corporation Steam Tug ‘Energy’ Preston Dock c.1900” by Preston Digital Archive