Yes, you're correct, a fine little river tug owned by C J king & Sons Ltd and built in 1936.
She has been preserved and is still working although now only taking passengers around Bristol City Dock.
She is featured in a DVD recently released by Snowbow Productions in their "Great Liners" series called "The Great Port of Bristol" produced by Des Cox ex NZ Co and Cunard, which involved some of my old cine films from the same era as my pictures.
Although I say it myself, it's a must for any Nostalgia fans.
Lovely photo of both ship and the river Avon, I have not seen so good a shot of the Avon in long time, Used to ply up and down the Avon, 1958 till early 1961 Sloans of Glasgow. Bought my first camera in Bristol Kodak sterling2 wish I had used it more, Thanks for sharing your photos.
That white house in the center of photo is the old gun Powder House, now a home of a brother of one of the members of SN. In the old days of sailing, ships were required to off-load their gun-powder before sailing up the river to the Bristol Harbor.