Ty Sunderland was pacing, his head bent intently over his phone. It was 5:52 p.m., eight minutes before 500 guests were expected to board the Circle Line Sightseeing Cruises boat where he was hosting a party on June 18, and the sound system had yet to be tuned.

Mr. Sunderland, 32, a D.J. and event producer who lives in Brooklyn, had begun firing off text messages to an engineer. The issue at hand threatened a choppy start to “Gayflower: Spice Girls,” this year’s inaugural installment of his annual Gayflower boat parties, which began in 2018 and are named after the Mayflower ship that ferried the pilgrims from England to Plymouth, Mass., in 1620.

Since the parties’ inception, each one has been a tribute to a different pop music act through both music and dress. Revelers, who are mostly gay men, often show up in outfits inspired by the artist being celebrated.