Airbnb is offering a free, two-night stay aboard the research vessel Alucia, coupled with an underwater dive on a submarine. All you have to do in order to spend April 5th–7th out at sea off of Cape Eleuthera in the Bahamas, is enter and win a competition. Contestants have to submit a 50- to 550-character essay about “what you dream of exploring beneath the waves.”

The Alucia is an 184-foot exploration vessel designed to conduct scientific research out in the ocean. The ship was used in the filming of Blue Planet II, the BBC documentary about the world’s oceans that premiered in the US on January 20th. In fact, Orla Doherty, one of the show’s producers, will be the host of the Airbnb contest, greeting winners on the vessel and telling them all about her own adventures diving over 500 hours beneath the surface. There are just a few “house rules” for the guests: no skinny dipping, no sleepwalking or night swimming, no fishing, no selfies with the deep sea creatures, and no high heels. (“This is a research vessel, not a cruise ship.”)