The submarine was designed to approach an enemy vessel, put the ends of the "tubes" out of the water, and blow up the ship with a combustible mixture. In addition, Nikonov designed an airlock for aquanauts to come out of the submarine and to destroy the bilge of the ship. With the death of Peter I in January 1725 Nikonov lost his principal patron and the Admiralty withdrew support for the project.[citation needed]