A propulsion control system for a marine vessel, the propulsion control system comprising: at least one propulsion device (12a, 12b) configured to propel the marine vessel; at least one proximity sensor system (70,72,74,76,78) configured to generate proximity measurements, wherein the proximity sensor system (70,72,74,76,78) is configured to generate a most important object dataset always containing at least four values defining one closest proximity measurement describing a proximity of an object with respect to the marine vessel in a positive X direction (90 +x), one closest proximity measurement describing a proximity of an object with respect to the marine vessel in a negative X direction (90 -x), one closest proximity measurement describing a proximity of an object with respect to the marine vessel in a positive Y direction (90 +y), and one closest proximity measurement describing a proximity of an object with respect to the marine vessel in a negative Y direction (90 -y); a controller configured to: receive the proximity measurements; access a preset buffer distance; calculate a velocity limit (113a-f) for the marine vessel in the direction of each object based on the proximity measurements and the preset buffer distance so as to progressively decrease the velocity limit (113a-f) as the marine vessel approaches the preset buffer distance from each object, wherein the controller is configured to calculate each of a positive X direction velocity limit based on the closest positive X direction proximity measurement (90 +x), a negative X direction velocity limit based on the closest negative X direction proximity measurement (90 -x), a positive Y direction velocity limit based on the closest positive Y direction proximity measurement (90 +y), and a negative Y direction velocity limit based on the closest negative Y direction proximity measurement (90 -y); and control the at least one propulsion device (12a,12b) such that a velocity of the marine vessel does not exceed the velocity limit (113a-f) in the direction of each object. at least one propulsion device (12a, 12b) configured to propel the marine vessel; at least one proximity sensor system (70,72,74,76,78) configured to generate proximity measurements, wherein the proximity sensor system (70,72,74,76,78) is configured to generate a most important object dataset always containing at least four values defining one closest proximity measurement describing a proximity of an object with respect to the marine vessel in a positive X direction (90 +x), one closest proximity measurement describing a proximity of an object with respect to the marine vessel in a negative X direction (90 -x), one closest proximity measurement describing a proximity of an object with respect to the marine vessel in a positive Y direction (90 +y), and one closest proximity measurement describing a proximity of an object with respect to the marine vessel in a negative Y direction (90 -y); a controller configured to: receive the proximity measurements; access a preset buffer distance; calculate a velocity limit (113a-f) for the marine vessel in the direction of each object based on the proximity measurements and the preset buffer distance so as to progressively decrease the velocity limit (113a-f) as the marine vessel approaches the preset buffer distance from each object, wherein the controller is configured to calculate each of a positive X direction velocity limit based on the closest positive X direction proximity measurement (90 +x), a negative X direction velocity limit based on the closest negative X direction proximity measurement (90 -x), a positive Y direction velocity limit based on the closest positive Y direction proximity measurement (90 +y), and a negative Y direction velocity limit based on the closest negative Y direction proximity measurement (90 -y); and control the at least one propulsion device (12a,12b) such that a velocity of the marine vessel does not exceed the velocity limit (113a-f) in the direction of each object. receive the proximity measurements; access a preset buffer distance; calculate a velocity limit (113a-f) for the marine vessel in the direction of each object based on the proximity measurements and the preset buffer distance so as to progressively decrease the velocity limit (113a-f) as the marine vessel approaches the preset buffer distance from each object, wherein the controller is configured to calculate each of a positive X direction velocity limit based on the closest positive X direction proximity measurement (90 +x), a negative X direction velocity limit based on the closest negative X direction proximity measurement (90 -x), a positive Y direction velocity limit based on the closest positive Y direction proximity measurement (90 +y), and a negative Y direction velocity limit based on the closest negative Y direction proximity measurement (90 -y); and control the at least one propulsion device (12a,12b) such that a velocity of the marine vessel does not exceed the velocity limit (113a-f) in the direction of each object.