A method of controlling propulsion of a marine vessel, the method comprising: receiving proximity measurements from one or more proximity sensors (72,74,76,78) on the marine vessel; limiting user input authority over propulsion output in a direction of an object by at least one propulsion device (12a,12b) based on the proximity measurements so as to maintain the marine vessel at least a buffer distance from the object; characterised by: controlling a user input device (22,28,29,30,32,34) to present a user input option to select at least one of a port side, a starboard side, a rear side, or a front side of the marine vessel for suspending the maintenance of the buffer distance; suspending the maintenance of the buffer distance from the object in response to a user-generated instruction, wherein the user-generated instruction specifies at least a selected one of the port side, the starboard side, the rear side, or the front side of the marine vessel; receiving user control input via a user input device (22,28,29,30,32,34) to move the marine vessel in the direction of the object; and controlling the at least one propulsion device (12a,12b) based on the user control input such that the marine vessel approaches and impacts the object. receiving proximity measurements from one or more proximity sensors (72,74,76,78) on the marine vessel; limiting user input authority over propulsion output in a direction of an object by at least one propulsion device (12a,12b) based on the proximity measurements so as to maintain the marine vessel at least a buffer distance from the object; characterised by: controlling a user input device (22,28,29,30,32,34) to present a user input option to select at least one of a port side, a starboard side, a rear side, or a front side of the marine vessel for suspending the maintenance of the buffer distance; suspending the maintenance of the buffer distance from the object in response to a user-generated instruction, wherein the user-generated instruction specifies at least a selected one of the port side, the starboard side, the rear side, or the front side of the marine vessel; receiving user control input via a user input device (22,28,29,30,32,34) to move the marine vessel in the direction of the object; and controlling the at least one propulsion device (12a,12b) based on the user control input such that the marine vessel approaches and impacts the object. controlling a user input device (22,28,29,30,32,34) to present a user input option to select at least one of a port side, a starboard side, a rear side, or a front side of the marine vessel for suspending the maintenance of the buffer distance; suspending the maintenance of the buffer distance from the object in response to a user-generated instruction, wherein the user-generated instruction specifies at least a selected one of the port side, the starboard side, the rear side, or the front side of the marine vessel; receiving user control input via a user input device (22,28,29,30,32,34) to move the marine vessel in the direction of the object; and controlling the at least one propulsion device (12a,12b) based on the user control input such that the marine vessel approaches and impacts the object.