Modular aquaculture fish pen assembly with slidable divider

A modular marine flotation collar for aquaculture applications is disclosed. Component collar segments are sealed by bulkheads including a connecting flange. Standard component collar segments may be assembled into a desired configuration by flange-to-flange connection of adjacent collar segments. A plurality of elongate tubular members having arcuate recesses conforming to the outer perimeters of supporting collar segments are arranged transversely atop the collar assembly so as to provide for the construction of an elevated walkway. The invention provides for a pen divider which is movable within the perimeter of the flotation collar for partitioning an area within the assembly.

BACKGROUND OF THE INVENTION 
The present invention is directed to a modular flotation support collar 
having a slidably adjustable pen divider, and to a method for construction 
thereof using interchangeable component parts. The method and component 
parts of the present invention are particularly suited for use in the 
construction of aquaculture fish pens. 
Growing consumer awareness in recent years of the health benefits accruing 
from lower consumption of saturated fats and cholesterol in the diet has 
resulted in reduced consumption of red meats and increasing demand for 
seafoods, particularly fish. Traditional harvesting techniques, however, 
have been unable to meet this growing demand for seafood due in part to 
limited, and in many cases decreasing, supplies of fish, particularly the 
more popular species such as salmon. Efforts to economically satisfy this 
growing demand for seafood have turned to aquaculture thereby nourishing 
the expansion of the fish farming industry. Fish pens are also used by 
private organizations and state and federal agencies in fish enhancement 
programs directed to particular species. 
Fish are typically grown in a system of moored or anchored fish pens. The 
pens are comprised of underwater net cages which permit good water flow 
through the pens. The upper portions of the net cages are supported by and 
secured to a buoyant surrounding structure such as a full perimeter 
floating collar assembly which supports an interconnecting decking 
structure such as walkways. The walkways, which generally include 
stanchions for supporting hand railings and net attachments, are used by 
fish farmers in the course of manual or automatic fish feeding, fish 
inspection, and storage of supplies, as well as for access to nets in the 
course of maintenance tasks. Flotation structures having spaced-apart 
flotation units expose the netting to damage from driftwood or other 
floating debris. Those structures having metal, styrofoam or wooden 
component parts are subject to damage from attack by salt water, 
petrochemical pollution or sea worms. When subjected to wave action, such 
flotation structures are frequently noisy and subject to excessive wear 
and reflex movements, all of which are disturbing to the fish and limit 
the life of the assembly. 
Full perimeter floating tubular collars made from single or double floating 
plastic pipes are becoming increasingly popular, particularly in 
environments prone to strong winds and significant wave action. Such 
collars provide substantial floating capacity while their position 
directly on the water surface offers a minimal profile to wind. The low 
profile also minimizes reflex movements due to wave action, resulting in a 
more gentle udulating motion transmitted to the net which, in turn, is 
less disturbing to the fish and contributes to increased yields. Such 
collars also act as a trash and log barrier substantially blocking debris 
from contact with the netting. 
In general, tubular support collars for marine applications are assembled 
from tubular segments filled with flotation material such as polystyrene. 
The abutting ends of adjoining segments are typically joined by an 
oversleeve which is welded to one end of a tubular segment and joined by a 
pin or similar connector to the adjacent tubular segment. Such 
connections, however, are not waterproof and are subject to infiltration 
by water which may eventually deteriorate the low density flotation 
material and reduce the collar buoyancy. 
A more serious problem is that the oversleeve must be large enough to 
readily slip over the tubular segments during assembly of the flotation 
collar--often in situ under adverse construction conditions. The 
tolerances required for assembly purposes creates looseness or "slop" in 
the joint connection. Wave action, working continuously on the loose joint 
slop may eventually cause the connection to weaken and fail. Collar 
segments of varying configurations are assembled end-to-end so as to 
construct a collar assembly of desired size and shape to suit a particular 
application. The assemblies described above, however, either require the 
transfer of fish during their growth to progressively larger pens or, in 
the alternative, require the periodic disconnection and reassembly of the 
collar assembly to achieve a required size. Such repeated on-site 
modifications are time consuming, costly and can result in accidental loss 
of fish. 
Finally, aquaculture flotation collar assemblies generally employ double, 
parallel tubular segments joined along their facing inner perimeters by a 
plurality of separators which serve as a support for planking or other 
walkway material. Such a walkway configuration is not only potentially 
unsafe for users because it is subject to "swamping" from even relatively 
minimal wave action, but is also subject to damage and fouling from marine 
contamination thereby requiring more frequent cleaning, repair, and/or 
replacement. 
A need exists for a modular flotation support collar assembly which is 
sealed from infiltration of water during use and in the course of in-water 
assembly, and for a method of joining component parts of such an assembly 
together with a connecting joint that will resist working apart due to 
wave action. A need also exists for such an assembly having walkways 
positioned above the reach of normally encountered wave action and for a 
modular flotation support collar assembly which permits pen enlargement 
during in-water use so as to accommodate fish growth without the need for 
costly and time consuming modifications to the collar perimeter. 
Summary of the Invention 
The present invention is directed to a marine flotation collar particularly 
suited for aquaculture applications which addresses the forementioned 
deficiencies of the prior art in a mutually compatible fashion. The 
invention provides for a watertight closure for sealing the open ends of 
each collar segment, the closure providing means for achieving a strong 
wave-resistant watertight joint connection. Collar segments of varying 
configurations are assembled end-to-end so as to construct a collar 
assembly of desired size and shape to suit a particular application. The 
invention provides for a fish pen assembly having a pen divider positioned 
within the perimeter of the pen so as to partition an area within the 
assembly. The pen divider includes connector means associated with at 
least one end of the pen divider for movably engaging the perimeter of the 
fish pen assembly and selectively adjusting the size of the partitioned 
area. 
In a preferred embodiment of the flotation collar assembly the watertight 
closures include a plurality of sealed bulkheads each having a peripheral 
connecting flange and joined by a watertight weld to the respective ends 
of each one of the collar segments so as to convert the collar segment 
into a sealed watertight enclosure. The flanged bulkhead closures serve to 
radially align and transmit torque between adjacent collar segments and to 
provide for durable interconnection of the collar segments. The connection 
means used for joining the respective flanges of abutting collar segments 
is preferably capable of being disengaged without damage to the flanges or 
to the collar assembly so as to allow for the addition, deletion or 
realignment of the sealed component collar segments which make up the 
collar assembly to respond to environmental or production requirements. 
Such connection means could include, for example, bolts received by 
respective aligned apertures in adjoining bulkhead flanges. 
Located on the top of the collar assembly are a plurality of elongate 
tubular members arranged transversely and welded to the collar segments, 
each tubular member formed to have an arcuate recess which conforms to the 
transverse outer perimeter of the respective collar segment. 
The pen divider includes connector means associated with one or more of the 
pen divider ends so as to enable the end of the pen divider to move 
longitudinally along one of the perimetrical members of the collar 
assembly. The connector means preferably include resiliently deformable 
channel means for receiving and retaining a portion of the pen perimeter 
within the channel means. The channel means preferably define an inner 
surface which conforms to the outer surface of the pen perimeter to be 
engaged. When the fish pen assembly includes opposing and parallel 
perimetrical members the ends of the pen divider may slidably engage 
opposing perimetrical members thereby permitting the pen divider to be 
easily shifted within the pen perimeter to a desired position without 
disassembly. In such configurations the divider itself is preferably 
comprised of two or more segments detachably joined so as to allow for 
engagement of both ends of the divider to the pen perimeter without 
requiring the disassembly of the perimeter. In one embodiment of the 
invention the connector means include a tubular sleeve having an outwardly 
directed longitudinal slot for receiving the pen perimeter. 
Accordingly, it is a principal object of the present invention to provide a 
watertight interconnection between adjoining segments of a marine 
flotation collar assembly. 
It is a further object of the invention to provide sealed and seaworthy 
connection means between adjacent collar segments. 
It is a further object of the present invention to provide individually 
sealed and seaworthy standard component collar segments which can be used 
to construct collar assemblies of various configurations. 
It is a still further object of the invention to provide for assembly 
modularity by permitting disengagement and reassembly of adjoining collar 
segments without damage to the components or infiltration of seawater. 
It is yet a further object of the invention to provide for the construction 
of an elevated walkway assembly alternatively on a single or multiple 
collar assembly design. 
It is a still further object of the present invention to provide a pen 
divider for partitioning of an area within the perimeter of a marine 
flotation collar assembly. 
It is a further object of the invention to provide a means for connecting a 
pen divider to an assembled marine flotation collar assembly. 
It is a further object of the present invention to provide for a connection 
means for a pen divider which is adapted to be movable along the perimeter 
of the collar assembly so as to be used to provide for various 
configurations for a partitioned area. 
It is a still further object of the invention to provide for a pen divider 
which can be easily and directly installed onto, or removed from an 
assembled collar perimeter assembly. 
It is yet a further object of the invention to provide for a pen divider 
having connector means for slidably varying the area partitioned by the 
divider without disassembly of the divider or collar perimeter. 
The foregoing and other objectives, features and advantages of the present 
invention will be more readily understood upon consideration of the 
following detailed description of the invention taken in conjunction with 
the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to the drawings, a preferred embodiment of the present invention 
is shown in FIG. 2 as comprising a marine flotation support collar 
assembly 10 for use in aquaculture fish pens, particularly in fish farming 
applications. The collar assembly floats at the water surface and serves 
to secure the upper periphery of an underwater net cage and thereby 
support the open netting at the water surface. The assembly 10 includes a 
plurality of elongate tubular segments 12. The segments are of a durable, 
light-weight plastic construction, such as a high molecular weight, high 
density polyethylene, which is impervious to water, highly resistant to 
puncturing and is resistant to fouling from ice, marine life and 
contamination. Such material can also be easily formed during manufacture 
to the required segment shapes and sizes. 
The example, the substantially rectangular assembly configuration shown in 
FIG. 2 includes a straight segment 12a, two right-angled segments 12b, and 
a "double-T" segment 12c. The modularity of the segments, as herein 
described below, provides sufficient interchangeability to achieve a 
variety of assembly configurations, two examples of which are 
schematically illustrated in FIGS. 3 and 4. Generally, the tubular 
segments 12 are filled with a low density material 14, preferably a 
plastic such as polystyrene, so as to maintain high buoyancy and to 
inhibit infiltration of water in the event of damage to the segments 12 or 
their interconnection. 
The ends of the tubular segments 12 are individually sealed by a heat or 
chemical weld to a bulkhead 18. As best seen in FIG. 5, the exemplary 
bulkheads 18 are circular, planar plates, preferably constructed of 
polyethylene, and having a diameter greater than that of the tubular 
segments 12. The intersection of a respective end of a segment 12 with the 
bulkhead 18 defines a flange 18a along the perimeter of the bulkhead. Each 
bulkhead 18 is provided with a plurality of apertures 18b positioned 
around the flange 18a and indexed so as to provide for alignment of the 
apertures of opposing pairs of bulkheads. 
The ends of the tubular segments 12 have a central axis A and are arranged 
so that an inner face 18c of a respective bulkhead 18 is transversely 
intersected by the central axis A. Watertight weld connections 16 
individually seal the interior of each tubular segment. When so sealed the 
segments 12 are assembled as illustrated in FIG. 6 to achieve a collar 
assembly of desired configuration by selecting adjoining component 
segments from among prefabricated segment shapes 12a, 12b, 12c and 
abutting the respective exterior bulkhead plate faces 18d so as to align 
the apertures 18b. The adjoining segments 12 are connected using a 
plurality of threaded bolts 12a each of which is received by an aligned 
pair of apertures 18b and removably secured therein by an opposing, 
threaded receiving nut 20b. Connection of the segments in this way forms a 
secure, watertight and torque transmitting junction of adjoining segments 
and constitutes a substantial improvement over prior art segment 
connections. 
Such prior art techniques, as seen, for example, in FIG. 1, secure 
adjoining segments 22a, 22b by employing a tubular sleeve 24 which fits 
over adjoining segment ends. Typically, the sleeve 24 would then be heat 
or chemically welded along the adjoining perimeter 23 to the first segment 
22a. The sleeve 24 and second segment 22b are held by a pin 26 secured 
transversely through the adjoining perimeter 25 of the sleeve and second 
segment. The inner diameter of the sleeve must be sufficiently greater 
than the outer diameter of the segment to allow the assembly of the 
flotation collar on site, often under adverse conditions. The tolerances 
required for assembly create a loose joint which can be worked by wave 
action, sometimes causing failure of the joint. Nor are such prior art 
connections watertight, allowing infiltration of water, particularly along 
the perimeter 25 and at the external protrusions of pin 26. 
As shown in FIG. 2, the collar assembly 10 may include a system of elongate 
tubular members 28 arranged in a horizontal plane transversely atop the 
segments 12. As best seen in FIG. 7, the members 28 each have a recess 30 
formed therein which conforms to the transverse upper perimeter 32 of a 
respective segment 12. The intersection of the recess 30 and perimeter 32 
are securely bonded by a weld. Of course, the members 28 could bridge a 
plurality of parallel segments 12. The horizontal plane defined by the 
members 28 support a walkway of wooden planking 34 or other suitable 
material. A vertical stanchion 36 may be constructed at the respective 
ends of the members 28 for receiving supports for a hand railing, not 
shown, and for supporting the upper perimeter of the netting sufficiently 
above the water surface to prevent the escape of fish from the pen. 
It should be understood that the watertight component segments of the 
collar assembly may be constructed in a manufacturing location and then 
transported to the "use" site where the component parts are assembled into 
fish pens of desired configuration. Preferably, the tubular members 28 
comprising the walkway support would be affixed to the component segments 
at the manufacturing location. 
FIG. 8 illustrates a marine flotation support collar assembly 10' having 
elements designated by primed reference numerals where constructed and 
assembled as previously described with regard to FIG. 2. The collar 
assembly 10' of FIG. 8 includes an exemplary pen divider 38 having two 
ends 40a, 40b interconnected by elongate tubular segments 42, 44a, and 
44b. The segments preferably are of a durable, lightweight, plastic 
construction, such as high molecular weight, high density polyethylene. 
The segments may be filled with a low density material 14', preferably a 
plastic such as polystyrene, so as to maintain high buoyancy and to 
inhibit infiltration of water in the event of damage to the segments 42, 
44a, 44b or their interconnection. Both ends of segment 42 and the 
respective inner ends of segments 44a, 44b are individually sealed by a 
heat or chemical weld to opposing bulkheads 18' as shown in FIG. 5. As 
seen in FIGS. 8 and 10 the segments 44a, 44b are then joined to a 
respective end of segment 42 in the manner previously described with 
regard to FIG. 6. An elongate tubular sleeve 46 is welded to each divider 
end 40a, 40b so as to cross perpendicular to the central axis of the pen 
divider at each end of the divider. The sleeve 46 is fabricated of a 
resilient material and includes an outwardly directed longitudinal slot. 
Referring to FIG. 10, the sleeve 46 defines a resiliently deformable 
channel 48 for receiving and retaining a tubular segment 12b' forming a 
perimetrical member of the collar assembly 10'. The deformable channel 48 
includes a restricted mouth 48a formed by the longitudinal slot and a well 
48b, defined by the interior of sleeve 46, which substantially corresponds 
dimensionally to the transverse dimensions of the perimetrical member to 
be received. The sleeve 46 is preferably fabricated of resilient plastic 
tubing having a diameter substantially identical to that of segment 12b' 
so as to obtain an inner surface 49 of the sleeve 46 which is in 
conforming relation to the outer surface of the tubular segment 12b' to be 
engaged. 
Referring to FIG. 10, the pen divider 38 is installed onto an assembled 
collar 10' by applying sufficient force to widen the longitudinal slot of 
resilient sleeve 46 sufficiently to receive and pass segment 12b'. As seen 
in FIG. 9, a snug engagement between the sleeve and the segment of the 
collar 10' is achieved when the segment 12b' is received in the sleeve and 
the force on the slot is released thereby permitting the sleeve to 
substantially return to its original shape and enabling channel 48 to 
receive and retain the segment 12b' therein. Once the segment 12b' is 
received in the sleeve, the narrowness of the slot, the resiliency of the 
sleeve and the friction between the inner surface of the sleeve and the 
outer surface of segment 12b' tend to retain the segment 12b' in the 
sleeve. 
Typically, the sleeves associated with the respective ends of the pen 
divider are engaged to their respective segments of the flotation collar 
while the divider is disassembled into at least two pen divider segments 
as shown in FIG. 10. When the pen divider segments are assembled, it will 
be understood that the outwardly facing slots on the sleeves help to 
retain the segments 12b' in the respective sleeves since the sleeves are 
prevented from disengaging movement by the interconnecting tubular 
segments 42, 44a and 44b. The pen divider thus contributes to the 
structural integrity of the fish pen assembly by providing an intermediate 
compression member between opposed perimetrical members. Bands or straps 
52 placed around the ends of the sleeves will ensure that the sleeves 
remain in engagement with the respective segments 12b' and will further 
add to the structural integrity of the fish pen assembly by enabling the 
pen divider to also act as a tension member. Once installed, the divider 
can be slid longitudinally along the opposing collar segments so as to 
vary the partitioned area within the collar assembly 10'. The divider 38 
may be used to secure a portion of the upper periphery of an underwater 
net cage or to support the upper periphery of an underwater divider within 
a net cage. 
To disassemble the pen divider, the elongate tubular segments are 
disconnected at a bulkhead flange connection and the short end of the pen 
divider may be slid along or pivoted about its segment 12b' to enable the 
respective sleeves 46 to be pulled off or disengaged by their associated 
segment 12b'. 
Although the exemplary embodiment of the pen divider is shown in 
association with parallel opposed perimetrical numbers, it is also 
possible to use the sliding comnnectors shown herein with pen dividers of 
other configurations. 
The terms and expressions which have been employed in the foregoing 
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.