Many thanks everyone,
Bob, .....the prop is a 2" brass 4 blade, which I made myself when I bulit a 1: 24 scale TID Tug many years ago.
It may not be obvious but this is all for a 1: 24 scale model of a Mersey Docks and Harbour Board, Survey Vessel called the AESTUS.
She was built in 1949 by W. Yarwood & Sons at Northwich in Cheshire, and I was fortunate to be able to abtaiin a copy of the plans from the MDHC. in about 1981. I think she was scrapped in 1988 or there abouts.
Peter