A boat, comprising: a hull (20,22) configured for flotation on water; a deck; a suspension system (40,50) positioned between the hull (20,22) and the deck and configured to suspend the deck with respect to the hull (20,22), the suspension system (40,50) further configured to accommodate pitch and roll motions of the deck with respect to the hull (20,22), the suspension system (40,50) also being configured to accommodate a heave motion of at least three feet of the deck with respect to the hull (20,22); a sensor configured to determine at least one inertial reference parameter of the deck; a controller coupled to the sensor and the suspension system (40,50), the controller being configured to control the suspension system (40,50) to maintain an orientation of the deck with respect to pitch, roll, and heave through a heave accommodation of at least three feet with a frequency response of the suspension system (40,50) less than or equal to 1 Hz; wherein: the suspension system (40,50) comprises a plurality active suspension systems (80,81,82,83); the sensor comprises a plurality of sensors (170,171,172,173), a separate one of the plurality of sensors (170,171,172,173) being adjacent a corresponding one of the plurality of springs (80,81,82,83); the controller comprises a plurality of controllers (180,181,182,183), a separate one of the plurality of controllers (180,181,182,183) being configured to control a corresponding one of the plurality of active suspension systems (80,81,82,83) based on an output from a corresponding one of the plurality of sensors (170, 171, 172, 173); and the sensor further comprises an inertial measurement unit to measure an inertial reference parameter for a central portion of the deck, the inertial measurement unit being coupled to each one of the plurality of controllers (180,181,182,183) for controlling the corresponding one of the plurality of active suspension systems (80,81,82,83); characterised in that: the plurality of active suspension systems (80, 81, 82, 83) comprises a plurality of air springs (80, 81, 82, 83), each of the air springs being coupled to an air tank and in that the controller is configured to dynamically control the air pressure in the air springs (80, 81, 82, 83). a hull (20,22) configured for flotation on water; a deck; a suspension system (40,50) positioned between the hull (20,22) and the deck and configured to suspend the deck with respect to the hull (20,22), the suspension system (40,50) further configured to accommodate pitch and roll motions of the deck with respect to the hull (20,22), the suspension system (40,50) also being configured to accommodate a heave motion of at least three feet of the deck with respect to the hull (20,22); a sensor configured to determine at least one inertial reference parameter of the deck; a controller coupled to the sensor and the suspension system (40,50), the controller being configured to control the suspension system (40,50) to maintain an orientation of the deck with respect to pitch, roll, and heave through a heave accommodation of at least three feet with a frequency response of the suspension system (40,50) less than or equal to 1 Hz; wherein: the suspension system (40,50) comprises a plurality active suspension systems (80,81,82,83); the sensor comprises a plurality of sensors (170,171,172,173), a separate one of the plurality of sensors (170,171,172,173) being adjacent a corresponding one of the plurality of springs (80,81,82,83); the controller comprises a plurality of controllers (180,181,182,183), a separate one of the plurality of controllers (180,181,182,183) being configured to control a corresponding one of the plurality of active suspension systems (80,81,82,83) based on an output from a corresponding one of the plurality of sensors (170, 171, 172, 173); and the sensor further comprises an inertial measurement unit to measure an inertial reference parameter for a central portion of the deck, the inertial measurement unit being coupled to each one of the plurality of controllers (180,181,182,183) for controlling the corresponding one of the plurality of active suspension systems (80,81,82,83); the suspension system (40,50) comprises a plurality active suspension systems (80,81,82,83); the sensor comprises a plurality of sensors (170,171,172,173), a separate one of the plurality of sensors (170,171,172,173) being adjacent a corresponding one of the plurality of springs (80,81,82,83); the controller comprises a plurality of controllers (180,181,182,183), a separate one of the plurality of controllers (180,181,182,183) being configured to control a corresponding one of the plurality of active suspension systems (80,81,82,83) based on an output from a corresponding one of the plurality of sensors (170, 171, 172, 173); and the sensor further comprises an inertial measurement unit to measure an inertial reference parameter for a central portion of the deck, the inertial measurement unit being coupled to each one of the plurality of controllers (180,181,182,183) for controlling the corresponding one of the plurality of active suspension systems (80,81,82,83); characterised in that: the plurality of active suspension systems (80, 81, 82, 83) comprises a plurality of air springs (80, 81, 82, 83), each of the air springs being coupled to an air tank and in that the controller is configured to dynamically control the air pressure in the air springs (80, 81, 82, 83).