Abstract:
A submersible raft device that is primarily used for aquaculture farming. The raft device has a raft surface, a buoyance support structure, and a submersion control system. The buoyance support structure and the submersion control system allow the raft to be submerged to a desired depth beneath the ocean surface. When used for certain kinds of aquaculture farming, such as mussel farming, submerging the raft below the surface protects the raft, as well as the mussels growing on ropes suspended from the raft, from damage in times of hazardous sea conditions.

Description:
BACKGROUND INFORMATION 
       [0001]    Field of the Invention 
         [0002]    The invention relates to the field of aquaculture farming. More particularly, the invention relates to a raft used for aquaculture farming. 
         [0003]    Discussion of the Prior Art 
         [0004]    Aquaculture farming, mariculture, or aquafarming, is the farming of aquatic organisms, such as oysters and mussels. One common method of aquaculture farming is through the use of a raft from which a number of ropes hang from the raft into the water. The ropes are seeded with aquatic organisms, which grow over time as they are suspended beneath the raft. When the organisms reach marketable size the ropes are brought to the surface and the organism removed. This method of farming produces large and healthy organisms. However, much of this farming occurs in open bodies of water where there are inherent difficulties from harsh weather and sea conditions. It is not uncommon for large numbers of oysters or mussels to fall from the ropes and be lost during such conditions. 
         [0005]    What is needed is a submersible aquafarming raft that can be submerged in times of extreme weather or drift ice. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    The invention is a submersible raft that may be used for aquaculture farming. The discussion of the submersible raft may hereinafter refer to a device that is used in aquaculture farming, and more specifically, mussel farming, but it is understood that the submersible raft may also be used for other purposes. 
         [0007]    The submersible raft according to the invention is an apparatus that is well-suited for use in aquaculture in ocean waters. Depending on the prevailing weather conditions, the raft is held in the water so that a raft surface is at or near the surface of the water, or is submerged below the surface. 
         [0008]    The submersible raft has a buoyancy support structure and a submersion control system that together allow the raft to be held selectively at or near the surface level of the water or submerged to a pre-determined depth. The buoyancy support structure includes a number of pontoons that are coupled to each other by a plurality of pontoon ties so as to form a flat support system for the raft surface. The raft surface is conventional, in that it is formed of surface elements, such as a plurality of planks, steel members, or timbers, or sheets of some suitable material, laid out across the buoyancy support structure. Ropes are attached to the surface elements and hang down below the raft surface. 
         [0009]    The submersion control system includes air and water control devices that allow the weight of the raft to be changed, in order to achieve a desired level of buoyancy. The pontoons are floodable with water, thereby increasing the weight of the structure and forcing it below the surface of the water. The amount of air and water in the pontoons is controllable, so that the raft may be submerged to a specific depth below the surface. 
         [0010]    The intended use of the raft according to the invention is as an aquaculture farm, for example, to grow mussels, oysters, etc. The aquatic cultures attach to the ropes or containers that are suspended from the raft surface. These aquaculture farms are typically in ocean waters and the rafts used are therefore exposed to the elements of the weather. 
         [0011]    Rough seas, ice, etc., can cause damage to the rafts and cause the aquatic cultures to fall from the ropes, particularly when the raft is at the surface of the water. Submerging the raft below the surface is an effective way to prevent crashing waves or ice from damaging the rafts. Depending on the particular weather that is forecast, the raft according to the invention may be submerged to the appropriate and desired depth. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The present invention is described with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. The drawings are not drawn to scale. 
           [0013]      FIG. 1  is a top perspective view of the device according to the invention. 
           [0014]      FIG. 2  is a perspective view of the device, showing aquatic culture ropes suspended beneath the raft. 
           [0015]      FIG. 3  is a top plan view of the surface of the raft, showing the raft surface and the float devices. 
           [0016]      FIG. 4  is a side elevation view of the floats and a single pontoon, showing multiple air bladders. 
           [0017]      FIG. 5  is a schematic diagram of a pontoon, showing the elements of the first embodiment of the submersion control system. 
           [0018]      FIG. 6  is a side view of a portion of the first embodiment of the pontoon submersion control system. 
           [0019]      FIG. 7  is a plan elevation view, showing a saddle mounted between a pontoon and the raft surface. 
           [0020]      FIG. 8  illustrates a support strap and a bracket for fastening the pontoon to the raft surface. 
           [0021]      FIG. 9  is a perspective view of a pontoon, showing saddle assembles coupling the raft surface to the pontoon. 
           [0022]      FIG. 10  is a top view of the raft, illustrating an air hose manifold attached to the surface of the raft. 
           [0023]      FIG. 11  is perspective view of aquatic culture ropes suspended from surface elements. 
           [0024]      FIG. 12  is a top view of showing the second embodiment of the pontoon submersion control system. 
           [0025]      FIG. 13  is a side view of a pontoon showing the second embodiment of the submersion control system. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    The present invention will now be described more fully in detail with reference to the accompanying drawings, in which the preferred embodiments of the invention are shown. This invention should not, however, be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be complete and will fully convey the scope of the invention to those skilled in the art. 
         [0027]      FIGS. 1, 2 and 3  illustrate a submersible raft  100  according to the invention that comprises a raft surface  10  that is supported on a buoyancy support structure  30 . A first embodiment of a submersion control system  40  that cooperates with the buoyancy support structure  30  to control the weight of the buoyancy support structure is shown in  FIGS. 5 and 6 . The raft surface  10  is conventional, in that it is formed of surface elements, such as a plurality of planks, steel members, or timbers, or sheets of some suitable material, laid out across the buoyancy support structure  30 . Ropes  70  are attached to the surface elements and hang down below the raft surface. Aquatic cultures, such as seed mussels, attach to the ropes  70 . The buoyancy support structure  30  provides the desired buoyancy, either keeping the raft  100  at or near the surface of the water or at a specified depth. The submersion control system  40  controls the amount of fluid that enters or exits the buoyancy support structure  30 , thereby controlling the weight and therefore the depth of the raft  100  in the water. The raft  100  is submerged during the winter, when rough seas are in the weather forecast, such as, for example, storms, hurricanes, periods of sea ice, and during other weather or sea conditions which could potentially cause damage to the raft  100  or the aquatic cultures. 
         [0028]      FIGS. 1, 2, 3 and 4  show the buoyancy support structure  30 , which includes a plurality of pontoons  31 / 31 A,  31 B,  31 C, etc. that are coupled to each other by a plurality of pontoon ties or connectors  20 . In the embodiment shown, three pontoons  31  are coupled together with the ties  20  to form the support structure  30 , but it is understood that, depending on the size of the particular raft  100 , different numbers of pontoons may be used. 
         [0029]      FIGS. 5 and 6  illustrate details of the first embodiment of the submersion control system  40 , which is used to control the buoyancy depth of the raft  100 . At least one each of an air bladder  34 , an inlet/outlet valve  38 , and a one one-way inlet valve  39  are provided in each pontoon  31 . The inlet/outlet valve  38  is connectible to an air hose (not shown) to pump air into or out of the air bladder  34 , and the one-way inlet valve  39  is used to allow water into the pontoon  31 . The air hose extends from the inlet/outlet valve  38  and connects to an air hose manifold  37 , shown in  FIGS. 2, 3, and 10  from which the air hose extends to the surface where air is pumped in or let out of the air bladder  34 . At least one one-way outlet valve  42  is provided on each pontoon  31 , to allow water and air to exit the pontoon. The embodiment shown contains two one-way outlet valves  42 A,  42 B, one on each end of the pontoon  31 . The air/water outlet valves  42 A,  42 B are connected to conduits  44 / 44 A,  44 B, that are connected to a perforated tube  46  that extends between the two conduits  44 A,  44 B. When the airbladder  34  is inflated, the water inside of the pontoon  31  is forced into the perforated tube  46  and then through the conduits  44 A,  44 B and out through the respective air/water outlet valve  42 A,  42 B. When water floods the pontoon  31  via the water inlet valve  39 , air in the pontoon  31  is forced into the perforated tube  46  through the conduits  44 A,  44 B and out of the pontoon  31  through the air/water outlet valves  42 A,  42 B. In addition, one or more small holes  48 , individually designated  48 A,  48 B, etc., are provided near the top of the conduits  44 A,  44 B to allow air to exit the pontoon  31  through the air/water outlet valves  42 A,  42 B. Air in the air bladder  34  is forced out through the air inlet/outlet  38  and exits through the air hose. 
         [0030]    Referring again to  FIGS. 1 and 2 , floats  60  are attached to the submersible raft  100  when it is submerged. The float devices  60  are connected to the raft surface  10  by float lines  62  in a manner that distributes the weight of the raft across the float devices  60 . The float devices  60  prevent the raft  100  from sinking below the desired depth in the event that the air to water ratio in the buoyance control system  30  cannot be set at a level that maintains the desired depth. The float devices  60  also provide additional buoyancy to support the raft  100  as the bivalves grow and additional weight is added to the raft  100 . 
         [0031]    In normal operating conditions, the raft  100  is held at or near the surface of the water. The ropes  70  are light at the early bivalve growth stage and the airbladders  34  in the pontoons  31  are filled with air to hold the raft  100  at or near the surface. When necessary or desired, the floats  60  and float lines  62  are attached to the raft  100  and the raft  100  is submerged as desired. 
         [0032]    The submersion control system  40  is used to submerge the raft  100 . First, at least one of the air inlet/out valves  38  that allow air to enter and exit the airbladder  34  is actuated. Water entering the pontoon  31  through at least one of the one-way valves  39  forces air out of the airbladder  34  and through the air inlet/out valve  38 , which is connected to an air hose (not shown). One or more pontoons  31  are flooded with water as needed, to submerge the raft  100  to a desired depth. In the embodiment shown, the air inlet/out valves  38  are actuated by levers  33  shown in  FIG. 10 . 
         [0033]    To raise a submerged raft  100  to the surface, the air hose that is connected to the air inlet/outlet valve  38  is attached to an air compressor and air is pumped into the airbladder  34 , which forces water out of the pontoon  31  through the air/water outlet valves  42 . 
         [0034]    In the embodiment shown, the buoyancy support structure  30  includes three pontoons  31 . The outer pontoons  31 A,  31 C, each have one airbag  34 . The middle pontoon  31 B has three airbags  34 A,  34 B,  34 C. When newly seeded with bivalves, the raft  100  is relatively light, so, to submerge it, a significant amount of weight needs to be added to the raft. In this case, all pontoons  31  are filled with water, which forces the air out of the buoyancy support structure  30  via the valves in the control system  40  and through the air hose. When the bivalves are half grown, however, the raft  100  is heavier and less weight needs to be added. In this case, one or more of the airbags in the middle pontoon  31 B are filled with air while the outer pontoons  31 A and  31 C are filled with water to submerge the raft surface  10  to the proper depth. When bivalves are fully grown, all three airbags  34 A,  34 B,  34 C in the middle pontoon  31 B are filled with air, and the outside pontoons  31 A and  31 C are filled with water. To raise the submerged raft  100 , the air bags  34  are inflated. 
         [0035]    In one embodiment, a set of air hoses (not shown) is used to provide air to the air bladders  34 . One end of the air hose is connected to the air bladder  34  and the other is connected to the air hose manifold  37 . Another air hose is connected to the manifold  37  and is attached to a buoy (not shown) and secured to the raft  100  by an acoustic release device  35 , such as Sonardyne Oceanographic Systems acoustic release transponder shown schematically in  FIG. 2 . To raise the raft  100 , the acoustic release device is actuated remotely by sending an acoustic signal to the device, which then releases the air hose and buoy, allowing them to rise to the surface where they are attached to an air compressor that provides air to the air bladders  34 . The non-connected end of the air hose may be attached to a quick disconnect air fitting, which is attachable to an air compressor to provide air to the air hose manifold  37  and then to the air bladder  34 . In another embodiment the buoy is not secured to the raft but is floating on the surface. 
         [0036]    In another embodiment, one end of an air hose is connected to an air bladder  34 , the air hose is secured to the float line  62  that connects the float  60  to the raft  100 , and the non-connected end is secured to the float  60  to ensure access at the surface of the water. The non-connected end may then be attached to an air compressor to provide air to the air bladder  34 . 
         [0037]    The submersible raft  100  may operate in a passive mode. When the floats  60  are connected to the raft surface  10  the submersion control system  40  may be actuated at the surface thereby submerging the raft  100  to a desired depth. Once submerged, the buoyancy support structure  30  and the floats  60  provide enough buoyancy to support the aquatic cultures as they grow for an extended period of time. The submersible raft  100  may also operate in an active mode, whereby additional air inlet/out valves  38  are actuated and, to raise the raft to a shallower depth, air is provided to the additional air bladders  34 , or to submerge the raft  100  to a greater depth air would be released from the additional air bladders  34  allowing water to enter the buoyance support structure  30 . 
         [0038]      FIGS. 12 and 13  illustrate second embodiments of the buoyancy support structure  30  and submersion control system  40 . As with the first embodiment, the buoyance support structure  30  includes a plurality of pontoons  31  that are coupled to each other by a plurality of pontoon ties  20 . The pontoons  31  may have one or more dividers  132  that create a number of airtight and watertight compartments  134  inside of the pontoon  31 . 
         [0039]    The second embodiment of the submersion control system  40  includes one or more water ports  142  and one or more air hoses  144 . The air hoses  144  are connected on one end to a port  145  located on the top side of the pontoon  31  and have a valve  146  on the opposite end to control the flow of air through the hose. The valve end of the hose runs to the water&#39;s surface where it is attached to some type of flotation device where it is accessible to an operator. 
         [0040]    In the embodiment shown, the water ports  142  are hoses or pipes that connect on one end to an opening  143  on the bottom on the pontoon  31  and that are open on the other end to allow water to enter and exit the compartment  134 . The water ports  142  may also be simple openings in the bottom of the pontoon  31 , however, pipes or hoses are advantageous as they also fill with air and prevent small amounts of air to exit and water to enter the pontoon when the raft  100  is at or near the surface and rough seas or waves cause the pontoons  31  to temporarily move above the surface of the water. Inlet/outlet valves (not shown) may also be added to the water ports  142  to prevent unwanted water from entering/exiting the pontoon  31 . 
         [0041]    The embodiment shown includes three pontoons  31 , each pontoon having one divider  132  and two compartments  134 A- 134 E. Each compartment has one air hose  144  and one water port  142 . When the raft  100  is deployed, the compartments  134  are filled with air and the air hoses are closed so as to prevent air from escaping the compartment  134  and the raft  100  floats at or near the surface of the water. 
         [0042]    To submerge the raft  100 , one or more of the valves  146  on the air hoses  144  are opened allowing air to escape the compartment  134 . As air exits the compartment  134 , water flows into the compartment  134  through the water port  142  and the weight of the water submerges the raft  100 . Additional compartments are filled with water to further submerge and/or balance the raft  100 . Preferably compartments  134 A,  134 B and  134 C are opened first, and then compartments  134 D,  134 E, and  134 F are opened. Compartments  134 B and  134 E are ideally situated to make minor adjustments to the depth of the raft  100 . 
         [0043]    To raise the submerged raft  100 , air is pumped into the compartments  134  through the air hoses  144 , forcing the water out through the water ports  142 . Preferably compartments  134 D,  134 E and  134 F are filled first, and then  134 A,  134 B,  134 C. Once the raft  100  is at the surface, the air valves  146  are closed. 
         [0044]      FIGS. 7, 8 and 9  illustrate the details of a saddle assembly  98  that fastens the pontoon tie  20  to the pontoon  31 . The saddle assembly  98  has a saddle  90  with a through-bore through which a threaded bar  92  is inserted. A bracket  99  is affixed to the underside of the raft surface  10 . Conventional fasteners, such as nuts and bolts, are used at the ends of the threaded bar  92  to fasten the ends of a support strap  50  to opposites sides of the saddle  90 , as well as to fasten the bracket to the raft surface  10 . An opening is provided between the saddle  90  and the pontoon  31  so that air hoses may run between them. Suitable fasteners  96 , such as, for example, U-bolts, are then used to secure individual pontoon ties  20  of the raft surface  10  to the buoyancy support structure  30 . 
         [0045]    In one embodiment, the saddle  90  is welded directly to pontoon  31  for additional structural support. In another embodiment, the bottom of the saddle  90  has a neoprene pad  94  that fits against the contour of the pontoon  31 , so that the strap  50  and fastener are prevented from slipping radially on the pontoon  31 . 
         [0046]    The ropes  70  are suspended from the raft surface  10 , which may be constructed with surface elements, such as a plurality of planks, steel members, timbers, or with a sheet of suitable material. In the embodiment shown, the raft surface  10  is shown constructed of a plurality of surface elements fastened to the top of the pontoon ties  20  as shown in  FIGS. 1, 2, 3 and 9  and the ropes  70  are suspended from the surface elements, as shown in  FIG. 11 . The raft surface  10 , buoyancy support structure  30 , submersion control system  40 , saddle assembly  98 , floats  60 , and ropes  70  are modular components that allow for convenient transport and assembly of the raft  100 . 
         [0047]    In another embodiment, the raft surface  10  has a plurality of upper support members  14 , shown in  FIG. 1 , that are attachable on top of the pontoon ties  20 . Reinforcing bars  16 , shown in  FIGS. 1 and 3 , that are fastenable to the pontoon ties  20  may be used to strengthen or stabilize the raft surface  10 . Structural support members  18  may also be provided for additional support where the raft surface is under the most stress. The support members  20 ,  14 ,  16 ,  18 , may be made of any suitable material. In the embodiment shown, for example, the pontoon ties  20  are steel, the upper support members  14  are timber, the reinforcing bars  16  are steel, and the structural support members  18  are steel C-channels. 
         [0048]    It is understood that the embodiments described herein are merely illustrative of the present invention. Variations in the construction of the submersible raft may be contemplated by one skilled in the art without limiting the intended scope of the invention herein disclosed and as defined by the following claims.