Green’s Dictionary of Slang

1. (orig. RN) unemployed, impoverished [ext. of SE; one is living as an impoverished beachcomber].

1908		Bulletin (Sydney) 16 July 15/1: He took my clothes, and he took my brass, and he threatened to run me in, / And said that I was a blessed fool to part with my hard-earned tin, / For he had me by the blessed ears fair beached in that rotten den – / But I promised myself I’d have my turn when we should meet again.
1925		(con. WWI) Fraser & Gibbons Soldier and Sailor Words 20: To be beached. To be turned adrift. Put out of employment.

2. (US teen) exhausted; stranded, abandoned [the imagery of a beached whale].

1997		S. Grimm The Lurker’s Guide to Babylon Five ‘Notes on Season 2 Episode 33’ 🌐 Remember Sheridan in ‘A Distant Star’ saying that he was feeling beached, abandoned? His unsureness in taking on this post, what if it was a mistake?
1999		S. Williams ‘Limits’ on Penn’s JD and Buck Page 🌐 Those annoying failures coupled with his current, seemingly unsuccessful, venture left him feeling beached and floundering. Even his partner’s usual optimism couldn’t pry him out of the funk he’d fallen into.