Hybrid fixed/floating marine structures

Abstract

A marine structure including a floating deck attached to a damper configured to control the vertical movement of the deck. The damper allows vertical motion of the floating deck in response to gradual changes in water level such as tidal changes, but resists bouncing of the deck in response to shorter term fluctuations in water level such as boat wakes or wind chop.

What is claimed is: 
     
         1 . A marine structure comprising:
 a buoyant deck configured to float on a body of liquid defining a liquid surface, the liquid surface defining a variable level and being subject to longer-term variation between an upper level and a lower level, the liquid surface also being subject to shorter-term fluctuations in level; and   at least one hydraulic damper in operative engagement with the buoyant deck, the at least one hydraulic damper configured to allow the buoyant deck to move up and down in response to the longer-term variation of the liquid surface level, but to resist movement of the buoyant deck in response to the shorter-term fluctuations in level.   
     
     
         2 . The marine structure of  claim 1 , wherein a portion of the at least one hydraulic damper is submerged in the body of the liquid. 
     
     
         3 . The marine structure of  claim 1 , wherein the at least one hydraulic damper receives liquid from and expels liquid to the body of liquid. 
     
     
         4 . The marine structure of  claim 1 , wherein the at least one hydraulic damper is positioned below the buoyant deck. 
     
     
         5 . The marine structure of  claim 1 , further comprising at least one piling, wherein the buoyant deck is coupled to the piling to retain the buoyant deck in fixed position horizontally and allow movement of the buoyant deck vertically relative to the piling. 
     
     
         6 . The marine structure of  claim 5 , wherein the at least one hydraulic damper is positioned within the at least one piling. 
     
     
         7 . The marine structure of  claim 1 , wherein the at least one hydraulic damper comprises a fixed housing defining an interior chamber, a piston head movable in the chamber, and a piston rod connected between the piston head and the buoyant deck. 
     
     
         8 . The marine structure of  claim 7 , wherein the proximal end of the fixed housing is coupled to a support surface below the buoyant deck. 
     
     
         9 . The marine structure of  claim 7 , wherein the proximal end of the piston rod is coupled to the buoyant deck and the distal end of the piston rod extends through the top of the fixed housing and couples with the piston head. 
     
     
         10 . The marine structure of  claim 8 , wherein the hydraulic damper further comprises a seal positioned in the chamber between proximal end of the chamber and the piston head. 
     
     
         11 . The marine structure of  claim 7 , wherein the piston head is configured to move within the chamber as the level of the water surface changes. 
     
     
         12 . The marine structure of  claim 11 , wherein the hydraulic damper further comprises at least one valve configured to control the rate of movement of the piston head relative to the change in water surface level. 
     
     
         13 . The marine structure of  claim 1 , wherein the buoyant deck comprises a surface configured for persons to traverse thereon. 
     
     
         14 . The marine structure of  claim 13 , wherein the buoyant deck is a dock. 
     
     
         15 . The marine structure of  claim 13 , wherein the buoyant deck is a pier. 
     
     
         16 . The marine structure of  claim 13 , wherein the buoyant deck is a swim platform. 
     
     
         17 . A hydraulic damper for a marine structure comprising a buoyant body afloat on a surface level of a body of water, the hydraulic damper comprising:
 a fixed housing defining an interior chamber at least partially filled with liquid;   a piston head positioned within the interior chamber and having a first face, a second face and an outer periphery, wherein the outer periphery of the piston head abuts an interior wall of the fixed housing to form a substantially water tight seal; and   a piston rod coupled at a first end to the piston head and at a second end to the buoyant body of the marine structure;   wherein the piston rod has a length, and wherein the length of the piston rod defines a distance between the buoyant body and the piston head; and   wherein the hydraulic damper permits vertical movement of the buoyant body in response to gradual changes in the surrounding water surface level but resists vertical movement in response to abrupt changes in the water surface level.   
     
     
         18 . The hydraulic damper of  claim 17 , wherein the outer periphery of the piston head includes a deformable gasket. 
     
     
         19 . The hydraulic damper of  claim 17 , wherein the piston head divides the chamber into an upper chamber and a lower chamber. 
     
     
         20 . The hydraulic damper of  claim 19 , further comprising at least one valve that allows fluid to move between the upper chamber and lower chamber. 
     
     
         21 . The hydraulic damper of  claim 20 , wherein the at least one valve is positioned on the piston head. 
     
     
         22 . The hydraulic damper of  claim 21 , further comprising a spring in between the first face of the piston head and the end of the fixed housing. 
     
     
         23 . The hydraulic damper of  claim 19 , wherein the fixed housing is at least partially submerged in a body of liquid and wherein each of the upper chamber and lower chamber includes at least one port allowing fluid to flow between the chamber and the body of fluid. 
     
     
         24 . The hydraulic damper of  claim 23 , wherein the at least one port on each of the upper chamber and lower chamber includes a valve configured to regulate the flow of liquid between each chamber and the body of fluid. 
     
     
         25 . The hydraulic damper of  claim 24 , wherein the valve is configured to open when there is a prescribed pressure differential between the pressure of the liquid in the chamber and the pressure of the liquid in the surrounding body of liquid. 
     
     
         26 . The hydraulic damper of  claim 23 , wherein the flow of liquid between each of the upper and lower chamber and the body of liquid allows the piston head to move within the chamber. 
     
     
         27 . A floating dock comprising a platform having sufficient buoyancy to float in a body of water, and a dampening mechanism allowing vertical movement of the platform in response to gradual changes in water level, but resisting vertical movement of the platform in response to short-duration changes in water level. 
     
     
         28 . A sub-aquatic dampening system for use in a body of water having a surface and a water level, the sub-aquatic dampening system comprising:
 a buoyant body configured to rest upon the surface of the body of water;   a hydraulic damper comprising a fixed housing defining an interior chamber, a piston head positioned within the interior chamber, and at least one variable pressure valve affixed to the fixed housing to regulate the pressure within the interior chamber; and   a piston rod connecting the buoyant body to the piston head of the hydraulic damper;   wherein the piston head is configured to move in response to changes in the water level, said movement being regulated by the at least one variable pressure valve.   
     
     
         29 . The sub-aquatic dampening system of  claim 28 , wherein the at least one variable pressure valve is configured to respond to long term changes in the water level, but resist short term changes in the water level. 
     
     
         30 . The sub-aquatic dampening system of  claim 29 , wherein the at least one variable pressure valve is configured to respond to a specified pressure differential between the interior chamber and the body of water.