A mast step for a kayak sailing rig is provided. The mast step supports a mast relative to a deck of the kayak at a desired angle to facilitate an optimum sail shape. The step also has a convex below a surface which contacts the deck, allowing the mast to be rotated forward or aft in use, and in particular allowing the mast to be rotated from an upright position to a flat position against the deck of the kayak.