Method of submerging floatation bodies and apparatus for performing same

Apparatus for submerging a floatation body for placement beneath a floating structure is comprised of a tank which is divided into at least two sealed compartments. The tank has a total gross weight which is greater than the buoyancy force of the floatation body and yet has a volume which will allow it to float when filled with air. In order to tailor the gross weight of the tank for use with floatation bodies having a range of buoyancies, weights are removably attachable to the tank. Fluid passageways are provided in the bottom of each compartment, and an air outlet, containing a control valve, is located near the top of each compartment to permit selective flooding of the compartment to submerge the tank. Air inlets entering the top of each compartment are provided with control valves to allow selectively refilling the respective compartments from a remote air generating system. The method includes attaching the floatation body to the tank with straps and opening the air outlet valves until sufficient water enters the tank through the fluid passageways to submerge the floatation body to a depth where it is located beneath the level of the structure. The submerged apparatus is then manipulated until the floatation body is located underneath the structure and pressurized air is forced into the tank from the air generating system through the air inlets, thereby displacing the water out of the compartments through the fluid passageways, until the floatation body is raised to a position where it is completely supported by the structure. The floatation body is then released from the apparatus by removing the straps, and the tank is raised to the surface by completely refilling it with air.

BACKGROUND OF THE INVENTION 
This invention relates to an apparatus for submerging a floatation body 
beneath a floating structure and the method by which this is accomplished. 
When a floating structure, such as a dock, houseboat, etc., ages it often 
loses buoyancy due to absorption of water which in turn causes the 
structure to list or even to become partially sunk. When this happens 
floatation bodies, such as styrofoam logs, are positioned under the 
structure in order to replace the buoyancy loss of the original structure. 
However, due to the large buoyancy force generated by these logs, it is 
difficult to locate them under the structure. 
Heretofore this operation has been performed mechanically, requiring large, 
expensive equipment which must be mounted on floating platforms when used 
in sites inaccessible by land. Thus placement of the logs, particularly a 
small number of them at a site which is remote from the normal operation 
of the equipment, is prohibitively expensive. In addition in many 
instances it is not possible to even bring the necessary equipment to the 
site at any cost, therefore making the operation impossible at these 
sites. 
SUMMARY OF THE INVENTION 
The present invention comprises a method and apparatus for inexpensively 
and easily positioning floatation bodies under a structure in order to 
augment the buoyancy of the structure. 
The apparatus includes a cylindrical tank which is divided into two sealed 
compartments. The tank has weight pockets attached to its sides so that 
its gross weight can be made greater than the buoyancy force of a wide 
range of floatation bodies. The pockets are located evenly on both sides 
of the tank and below its horizontal centerline so that when symmetrically 
filled with weights the tank is stabilized and prevented from rolling 
about its longitudinal axis. The tank has a volume which will allow it to 
float when filled with air even with the weights installed. 
Straps for securing logs to the tank are fixedly attached to the tank at 
one of their ends and are adjustably attached to it at their other ends by 
means of buckles. Thus the length of the loops formed when the buckles are 
fastened is adjustable thereby allowing the straps to encircle logs of 
differing diameters. 
Located at the top of each compartment is an air outlet having a valve for 
regulating the airflow through the outlet or closing it altogether. In the 
bottom of each compartment is a fluid passageway which is always open. 
Accordingly by opening the valves in the air outlets the tank is flooded 
with water through the fluid passageway as air is forced out of the air 
outlet thus submerging the tank. 
Air inlet means, also having a control valve located in it, is located on 
the top of each compartment and is connected to an air generation source 
located remotely of the apparatus. Thus once submerged, the tank can be 
raised again by introducing pressurized air into the tank through the air 
inlet to displace the water from the tank through the fluid passageways. 
The method of using the apparatus comprises fastening a floating floatation 
body to the tank by means of the straps. The tank then is flooded by 
opening the air outlet valves and allowing water to enter through the open 
fluid passageways. Once the tank is submerged to a position where the 
floatation body is located below the level of the structure, the apparatus 
is pushed under the structure by a diver. Air from the above water 
generation source is then pumped into the compartments through the air 
inlet valves thereby displacing water through the fluid passageways. When 
sufficient water has been displaced to raise the tank to a level where the 
floatation body is completely supported beneath the structure, the air 
inlet valves are closed. 
The floatation body is then released by unfastening the straps and the tank 
is pushed free of the structure leaving the floatation body in place to 
help support the structure. The tank is then completely filled with air to 
bring it up to the surface for pickup of another log. 
It is an objective of the present invention to provide a method for 
submerging floatation bodies which does not require expensive equipment. 
It is a further objective of the present invention to provide such a method 
which allows placement of the bodies quickly and easily. 
It is a further objective of the present invention to provide such a method 
which doesn't require the use of highly trained operators. 
It is a still further objective of the present invention to provide an 
apparatus which facilitates the operation of the aforesaid method. 
The foregoing and other objects, features, and advantages of the principal 
invention will be more readily understood upon consideration of the 
following detailed description taken in conjunction with the accompanying 
drawings.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIG. 1 of the drawings, the apparatus of the present invention 
comprises a tank 10, which is shown as being cylindrical and which is 
divided into two equal volume compartments by a central divider 12. The 
compartments are sealed so that the tank will float when placed in water, 
however preferably the tank is constructed from a heavy material, such as 
steel, so that it floats low in the water. In addition weights 14 are 
attached to the tank along both of its sides to further lower the level at 
which the tank floats. The weights are located below the horizontal 
centerline of the tank and are distributed evenly on both of its sides to 
provide rotational stability to the tank, both when it is floating and 
when it is submerged. In the embodiment illustrated the weights are 
releasably located in pockets 16 which are attached to the tank to provide 
flexibility in setting the net weight of the tank. 
When weights 14 are in place, the gross weight of the tank is greater than 
the buoyancy force of a floatation element, such as a styrofoam log, which 
is to be submerged by the apparatus. Thus by varying the amount of weights 
14 which are added, the tank can be used for submerging logs having a wide 
range of buoyancy forces. However, as noted above, the size of the tank is 
sufficient that when it is filled with air it has adequate buoyancy to 
float itself and weights 14. 
Straps 20 are provided for releasably securing log 18 to tank 10. The 
straps are fixedly attached to the tank at one of the their ends and are 
adjustably fastened at their other ends by buckles 22. Thus the length of 
the loops formed by the straps is adjustable to accommodate logs of 
various sizes. 
Located at the tops of each compartment is air outlet means, such as tube 
24, having a manually operated valve 26 located therein. Fluid passageway 
means, such as pipe 28, opens into each compartment at the bottom of the 
tank. Accordingly, by opening valves 26 the respective compartments can be 
selectively flooded through pipes 28, thereby submerging the tank to 
whatever level is desired. 
Air inlet means, such as manifold 30, enters each compartment proximate the 
top of the tank for refilling the tank with air when it is to be 
resurfaced. Control valves 32 are located in the manifold adjacent to each 
compartment to allow selectively controlling the air entering the 
respective compartments. An air line 34 interconnects the manifold and a 
compressor (not shown), or other means of generating pressurized air, 
which is located on the surface. 
The method by which the above-described apparatus is used to submerge a 
floatation body is shown sequentially in FIGS. 2-5. Prior to use 
sufficient weights 14 are added to pockets 16 to make the gross weight of 
tank 10 greater than the buoyancy of the styrofoam log 18 which is to be 
submerged. Since the weight pockets are located below the horizontal 
centerline of the tank, when weights are added the tank is rotationally 
stable both when surfaced and when submerged. With the apparatus and the 
log floating near the structure 36 which is to be supported, the log is 
secured to the tank by wrapping straps 20 tightly around the log and 
fastening them to buckles 22, FIG. 2. 
The tank, and thus the log, then is submerged, FIG. 3, by opening valves 
26, thus allowing air to be displaced from the respective compartments 
through tubes 24 by water which enters the tank through pipes 28. It will 
be noted that by dividing the tank into compartments, with each having 
individual fluid passageways and air inlet means, the attitude of the tank 
can be controlled during flooding by selective manipulation of valves 26. 
Otherwise air pockets could form at one end of the tank causing it to 
become unstable and roll end over end as air is evacuated. Once the log is 
submerged to a level below the bottom of structure 36, the apparatus and 
log are manipulated, by means such as a diver, to a position wherein the 
log is properly located beneath the structure. 
The log is then raised until its buoyancy force is completely transferred 
to the floating structure, FIG. 4, by refilling the tank with air. 
Pressurized air from a remote source, such as a compressor and storage 
tank (not shown), is supplied through line 34 and manifold 30 into the 
respective compartments by opening the associated valves 32. Thus water is 
forced out of pipes 28 thereby increasing the buoyancy of the tank. 
However, the tank is not completely refilled with air but only sufficient 
air is introduced to raise the tank to a level wherein the log is 
supported by the structure. Then straps 20 are removed from the log and 
the apparatus is maneuvered out from under the structure. 
It will be noted that by introducing air selectively into both 
compartments, the tank can be maintained horizontal while it is raised, in 
the same manner as when it was lowered. 
The apparatus then is raised to the surface, FIG. 5, by fully refilling the 
compartments with air in the same manner as just described. At this point 
the apparatus is ready to be attached to another log 18a and the process 
repeated. 
The terms and expressions which have been employed in the foregoing 
abstract and specification are used therein as terms of description and 
not of limitation, and there is no intention in the use of such terms and 
expressions of excluding equivalents of the features shown and described 
or portions thereof, it being recognized that the scope of the invention 
is defined and limited only by the claims which follow.