A jack-up vessel

Abstract

A jack-up vessel has a buoyant hull, a plurality of jack-up legs including leg chords having racks, and jacking assemblies to relatively move the associated leg chord relatively to the buoyant hull vertically. The jacking assemblies include actuators and a pinion group, including a plurality of pinions arranged vertically above each other. Jacking assemblies include a sensor system for sensing the load distribution associated with a pinion group. The jack-up vessel includes a control system configured for receiving information about an intended use and/or future environmental conditions and determining a pre-operation load distribution over the pinions in the pinion group, in which pre-operation load distribution the loads within this pinion group are unequally distributed, such that during the intended use and/or during the future environmental conditions the loads within this pinion group are equally distributed.

1 . A jack-up vessel, the jack-up vessel comprising:
 a buoyant hull;   a plurality of jack-up legs, each jack-up leg comprising one or more leg chords, each leg chord having at least one rack;   a plurality of jacking assemblies, each jacking assembly being associated with a leg chord and being configured to vertically move the associated leg chord relatively to the buoyant hull,   wherein each jacking assembly comprises:
 a pinion group comprising a plurality of pinions arranged vertically above each other, each pinion engaging the rack of a leg chord and being configured for transferring load between the hull and the leg chord resulting in a load distribution over the plurality of pinions within the pinion group; 
 actuators for actuating the pinions of the pinion group, each actuator being configured for actuating a corresponding pinion; and 
 a sensor system configured for sensing the load distribution over the plurality of pinions associated with each pinion group, and configured for emitting sensor signals indicative of the sensed load distribution; and 
   a control system configured to perform a routine comprising:
 receiving information about an intended use and/or about future environmental conditions for the jack-up vessel; 
 determining, based on the received information, a pre-operation load distribution over the plurality of pinions of the pinion group, in which pre-operation load distribution the loads over the pinions within the pinion group are unequally distributed, such that in an operational load distribution during the intended use and/or during the future environmental conditions, the loads over the pinions within the pinion group are equally distributed; 
   receiving the sensor signals indicative of the sensed load distribution, and determining/computing a difference between the pre-operation load distribution and the sensed load distribution; and   emitting, in response to the difference, control signals to the actuators, such that the actuators are operated and the sensed load distribution of the pinion group is made to correspond to the pre-operation load distribution.   
     
     
         2 . The jack-up vessel according to  claim 1 , wherein the pre-operation load distribution for the plurality of pinions of the pinion group is such that one or more lower pinions of the pinion group have lower loads thereon than one or more higher pinions of the pinion group. 
     
     
         3 . The jack-up vessel according to  claim 1 , wherein a load increase from the pre-operation load distribution to loads in the intended use and/or during the future environmental conditions for one or more lower pinions of the pinion group is larger than for one or more higher pinions of the pinion group. 
     
     
         4 . The jack-up vessel of according to  claim 1 , wherein the control system is configured to determine the pre-operation load distribution for each pinion group individually. 
     
     
         5 . The jack-up vessel according to  claim 1 , wherein the control system is configured to determine the pre-operation load distribution for each of the pinion groups corresponding to a jack-up leg. 
     
     
         6 . The jack-up vessel according to  claim 1 , wherein the jack-up vessel comprises a crane. 
     
     
         7 . The jack-up vessel according to  claim 6 , wherein the pre-operation load distribution is calculated on the basis of a hoisting load of the crane. 
     
     
         8 . The jack-up vessel according to  claim 1 , wherein the control system further comprises a user interface to receive information about an intended use and/or future environmental conditions from an operator. 
     
     
         9 . A method for operating a jack-up vessel the jack-up vessel comprising:
 a buoyant hull;   a plurality of jack-up legs, each jack-up leg comprising one or more leg chords, each leg chord having at least one rack;   a plurality of jacking assemblies, each jacking assembly being associated with a leg chord, each jacking assembly being configured to vertically move the associated leg chord relatively to the buoyant hull,   wherein each jacking assembly comprises:
 a pinion group comprising a plurality of pinions arranged vertically above each other, each pinion engaging the rack of a leg chord and being configured for transferring load between the hull and the leg chord resulting in a load distribution over the plurality of pinions within the pinion group; 
 actuators for actuating the pinions of the pinion group, each actuator being configured for actuating a corresponding pinion; and 
 a sensor system configured for sensing the load distribution over the plurality of pinions associated with each pinion group, and configured for emitting sensor signals indicative of the sensed load distribution; and 
   a control system,   the method comprising the steps of:   operating the jacking assemblies to lower the jack-up legs for engagement with a seabed and raising the buoyant hull to a distance above a water level;   receiving information about an intended use and/or about future environmental conditions;   determining, based on the received information, a pre-operation load distribution over the plurality of pinions of a pinion group, in which pre-operation load distribution the loads over the pinions within the pinion group are unequally distributed, such that in an operational load distribution during the intended use and/or during the future environmental conditions, the loads within the pinion group are equally distributed;   sensing an actual load distribution associated with the pinion group, and emitting sensor signals indicative of the sensed load distribution;   the control system receiving the sensor signals indicative of the sensed actual load distribution and determining/computing a difference between the pre-operation load distribution and the sensed actual load distribution; and   the control system emitting, in response to the difference, control signals to the actuators such that the actuators are operated and cause the sensed actual load distribution of the pinion group to correspond to the pre-operation load distribution.   
     
     
         10 . (canceled) 
     
     
         11 . The method according to  claim 9 , wherein the pre-operation load distribution for the plurality of pinions of the pinion group is such that one or more lower pinions of the pinion group have lower loads thereon than one or more higher pinions of the pinion group. 
     
     
         12 . The method according to  claim 9 , wherein a load increase from the pre-operation load distribution to loads in the intended use and/or during the future environmental conditions for one or more lower pinions of the pinion group is larger than for one or more higher pinions of the pinion group. 
     
     
         13 . The method according to  claim 9 , wherein the control system determines the pre-operation load distribution for each pinion group individually. 
     
     
         14 . The method according to  claim 9 , wherein the control system determines the pre-operation load distribution for each of the pinion groups corresponding to a jack-up leg. 
     
     
         15 . The method according to  claim 9 , wherein the jack-up vessel comprises a crane, and wherein the pre-operation load distribution is calculated on the basis of a hoisting load of the crane. 
     
     
         16 . The method according to  claim 9 , wherein said receiving information about an intended use and/or about future environmental conditions comprises receiving information about a predicted storm.