Shark is an ironborn longship and a member of the Iron Fleet.
A Dance with Dragons
The Shark is part of the Iron Fleet contingent dispatched to Slaver's Bay. Violent storms east of the Stepstones leave the Shark little more than a hulk, so Victarion Greyjoy decides to leave her behind at the rendez-vous point, off the southern tip of the Isle of Cedars, to make repairs and to alert stragglers to the current plan. After leaving the Shark behind, the ironborn fleet bound for Slaver's Bay numbers fifty-three.