The invention relates to improvements to masts and in particular a mast apparatus (17) for raising and/or lowering a mast (18) on a vessel such as a vessel, and a vessel incorporating such a mast apparatus. In one example embodiment, the mast apparatus for raising and/or lowering the mast on a vessel comprises a mast; a mast housing (28); a pivot (44) for the mast fixedly connected to the mast housing; a lateral movement control mechanism (34) for enabling controllable lateral movement of the mast with respect to the pivot and the mast housing; a lateral movement control mechanism such as hydraulic ram (30) connected to the mast and connected to the mast housing, or connected to the mast and connectable to a vessel, for driving the mast to rotate about the pivot and move laterally under the control of the lateral movement control mechanism so as to raise or lower the mast and move the mast laterally in a controlled manner.