Is this term unique to S/Ms? In big ships the most junior engineer officer had 'Outside Machinery' as his part of ship, meaning everything outside the boiler and engine rooms. I have a vague feeling he may have been called the Outside Wrecker but, not being a plumber, I can't confirm this.
As far as I know the word â€˜Scratcherâ€™ derived from the fact that he was scratching after the Coxswain Jobâ€™ Being one myself many years ago I did the job of running the boat on several occasions until I was recommended for Coxâ€™n. When I became a 2nd Coxâ€™n I was only a UW3, so never held a 2nd class rate becoming an Acting Chief from then on as a Coxâ€™n,. My trade certificate says I was a Coxâ€™n for 11 years and 7 months but I was only made a proper Chief for the last six of my Service.
â€˜Outside Wreckerâ€™ is of course a different kettle of fish, in the first place it was always an ERA1 whose job it was to look after and maintain all the machinery not in the ER and as â€˜tiffiesâ€™ had a reputation of â€˜If it donâ€™t work, get a bigger hammer!!?â€™. Hence the word Wrecker.