Boarding a sinking ship
Band-term. After one band member decided to quit the band, all the other members already know that it's over but they decide to put up an add for a replacement anyway "just to see where we can take this anyway". After the new recruit joins this band with the enthousiasm of a young pup and probably got himself new "gear" just for this occasion, a month in or so after some half-assed rehearsals the whole band decides to call it quits.
"I got a new bass, a new amp, quit my job so I could make it to all the rehearsals, wrote five songs, and then they decide to quit!"
"Sounds like you we're boarding a sinking ship!"
"Sounds like you we're boarding a sinking ship!"