A Brooklyn high-school principal who allowed chaperones to booze it up on a senior-prom boat ride — and paid teachers overtime to attend — is cruising into the sunset.

Michael Soet, of International HS at Lafayette, told staff he’s quitting in June.

Soet paid overtime for 15 teachers to attend the June 2009 prom, where a drunken female chemistry teacher locked lips with a student, as The Post reported.