According to Genesis, water covered Noah’s Ark after the Flood began. The narrative says the waters rose until even the high mountains under the heavens were covered, leaving the Ark floating above the flooded earth.
Genesis describes the Flood as coming from two sources: rain falling from the sky and the bursting open of the “fountains of the great deep.” The account then follows the rise, persistence, and gradual recession of the waters. The Ark was designed to preserve its occupants while the land remained submerged.
This question concerns what surrounded and supported the Ark during the Flood, not the material used to seal it. Genesis says Noah coated the vessel with pitch, while the Flood itself consisted of water. The narrative later says the waters receded and the Ark rested on the mountains of Ararat.