A variable geometry sea anchor mountable on a watercraft such as a boat for controlling drift of the watercraft including: a support structure mountable to a deck portion of the watercraft; a mast support assembly adjustably mounted to the support structure ; characterised in that a mast assembly is operatively interconnected to the mast support assembly comprising: a support frame adjustable substantially simultaneously by the mast support assembly in: a first plane between a storage orientation and an operational orientation, and a second plane between a storage geometry and a drift control geometry; a web sheet mounted by the support frame , the web sheet being movable by the support frame to provide effective drift control in the drift control geometry; at least a first actuator mounted on the support structure , and operably connected to the mast support assembly to selectively control the orientation of the support frame of the mast assembly, wherein in a drift control operating condition the at least first actuator acts on the mast support assembly to effect change in the orientation of the support frame in the first plane between the storage and operational orientation, and wherein the support frame is configured to change geometry in the second plane so that the combined support frame and web sheet adopts an operating configuration effective to control drift of the watercraft. a support structure mountable to a deck portion of the watercraft; a mast support assembly adjustably mounted to the support structure ; characterised in that a mast assembly is operatively interconnected to the mast support assembly comprising: a support frame adjustable substantially simultaneously by the mast support assembly in: a first plane between a storage orientation and an operational orientation, and a second plane between a storage geometry and a drift control geometry; a web sheet mounted by the support frame , the web sheet being movable by the support frame to provide effective drift control in the drift control geometry; at least a first actuator mounted on the support structure , and operably connected to the mast support assembly to selectively control the orientation of the support frame of the mast assembly, wherein in a drift control operating condition the at least first actuator acts on the mast support assembly to effect change in the orientation of the support frame in the first plane between the storage and operational orientation, and wherein the support frame is configured to change geometry in the second plane so that the combined support frame and web sheet adopts an operating configuration effective to control drift of the watercraft. a first plane between a storage orientation and an operational orientation, and a second plane between a storage geometry and a drift control geometry; a web sheet mounted by the support frame , the web sheet being movable by the support frame to provide effective drift control in the drift control geometry; at least a first actuator mounted on the support structure , and operably connected to the mast support assembly to selectively control the orientation of the support frame of the mast assembly, wherein in a drift control operating condition the at least first actuator acts on the mast support assembly to effect change in the orientation of the support frame in the first plane between the storage and operational orientation, and wherein the support frame is configured to change geometry in the second plane so that the combined support frame and web sheet adopts an operating configuration effective to control drift of the watercraft. <EOS>