Abstract: 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.

Abstract: A pontoon for supporting a dock structure in the water includes a core member of buoyant material encased in a plastic closure member. Bottom and top walls of substantially the same dimensions are substantially parallel with each other and are interconnected by slightly rounded sidewalls. The thickness of the pontoon is substantially reduced with respect to its width. The core is advantageously made of extruded styrofoam and attached to the dock structure by through bolting.

Abstract: A float system comprised of modular units assembled to form relatively rigid floating assemblies in a plurality of configurations is provided. In a preferred embodiment comprising a basic two-tier assembly, the modular units form upper and lower layers which combine to define a buoyant, protected shell. The units are preferably interchangeable so that they may be used for either the upper or lower layer and are assembled in a staggered manner to form overlapping connections. The modular units may be assembled using a buoyant lower layer and a non-buoyant upper layer, or using more than two buoyant layers if desired. Preferred embodiments for unevenly loaded structures include multilayer portions at locations on the structure corresponding to increased loads.

Abstract: A floating pier structure comprising a floating platform, an anchored base, and an articulated, parallelogram linkage structure pivotably connecting the platform to the base so that the platform will remain substantially level on the surface as water conditions change. The linkage is also pivoted to the base so that the platform can be swung into shore without disassembly.

Abstract: A buoyant support unit and platform employing the same which includes at least five substantially cylindrical floatable pipes having a diameter of less than about 5 meters which are arranged parallel to each other in spaced-apart relationship, wherein the edge to edge distance between adjacent pipes is from 0.25 to 2.0 times the diameter of the pipe.

Abstract: A monocoque decking has a surface of cured polymeric material, and a selected quantity of stone particles of predetermined nature disposed and fixed thereupon. A method of forming the decking is also described.

Abstract: A construction transportation system comprises at least one transport assembly having gross dimensions generally corresponding to those of a standard freight container. The transport assembly comprises at least two construction components. Each of the two construction components has a first gross dimension whose maximum value is generally equal to C.sub.1 /x, where C.sub.1 is the width of a standard freight container, and x is greater than or equal to 1. Each of the two components has a second gross dimension perpendicular to the first dimension whose maximum value is generally equal to C.sub.2 /y, where C.sub.2 is the length of a standard freight container, and y is greater than 1. Each of the two components has a third gross dimension perpendicular to the first and second dimensions. At least a first side of each of the two components extends in the directions of that components' first and third dimensions, and that first side is provided with connectors.

Abstract: A construction transportation assembly comprising a buoyant general construction component having eight corner portions defining a rectangular parallelpiped locus with a length and a width generally corresponding to those of an ISO standard freight container, and two specialty components mounted on top of the general component laterally adjacent each other and lying within the length and width of the locus.

Abstract: Polyethylene float drums are constructed as modules, in various configurations, and then assembled into various modular systems to float a variety of structures. All float drum modules utilize at least one flat, perpendicular side wall to insure accurate assembly of the float drum modules into a flanged load bearing modular float assembly having desired float characteristics.

Abstract: This invention relates to a modular float, which is in the form of an integral, closed shell, hollow float that is light weight portable and easy to use. It is intended to support marine devices such as docks, rafts and the like. The modular float has two side walls, two end walls extending between the side walls, and a generally rounded lower portion and generally rectangular upper portion, both when viewed from one side. The upper portion has a number of intersecting grooves, which are designed to carry standard sized support members, which in turn carry a deck. The grooves have resilient ridges for releasably engaging the support members.

Abstract: A pontoon unit capable of folding up in a W-like manner. The two inner pontoons are connected by a center hinge, and the outer pontoons are pivotably connected to the inner pontoons by lower hinges via a lever. As an aid to overcome the buoyancy during unfolding, a tension spring is arranged between the lever and the outer pontoon. This spring is tensioned in the folded condition. After unfolding, the tension spring is virtually relaxed, and would be tensioned again for folding. This is avoided by interposing a variable-length connection member, typically a hydraulic piston/cylinder unit, between the tension spring and the outer pontoon. By being extended, this connection member avoids the need for the tension spring to be tensioned during folding. Only after the folding operation has been completed is the tension spring tensioned again by shortening the connection member.

Abstract: Floating structures, for example, for recreational aquatic activities, comprises a plurality of individual uniquely-constructed modular flotation units constructed to permit any desired freeboard dimension and/or buoyancy characteristics.

Abstract: A marine float for use in conjunction with a concrete floating dock system and methods for manufacturing the same. The float consisting of a buoyant core of expanded polystyrene foam supporting a textured deck of standard aggregate concrete and surrounded by a shell of fiberglass reinforced cement. The float is fabricated as a unitary whole by pouring a layer of standard aggregate concrete in a form over a texturing mat to provide the textured deck, placing a buoyant element over the poured deck and spraying a layer of fiberglass reinforced cement around the buoyant element before any of the concrete elements has set. All concrete elements are then permitted to set to form a monolithic float.

Abstract: A floating dock includes a plurality of float modules comprised of containers having opposing walls, a deck with opposing edges mounted in spaced relationship above the float modules, and a pair of wales extending along opposing walls of the float modules and opposing edges of the dock. Compression rods extend between the wales above the modules and act on the pair of wales such that the compression rods exert compression force on the float modules and deck. A compression beam extends between the opposing walls of the container below the compression rod to create a box beam in combination with the wales and deck, therefore rigidifying the dock to enhance its portability on land and wave resistance properties in water. The float modules are spaced apart longitudinally of the dock to allow wave transparency and wash space for debris.

Abstract: An artificial breakwater which dynamically changes shape and thus absorbs both surface and undersurface wave energy with varying wave height. The breakwater elements are flexible and extensible walled bags of which a major part is to be submerged below the surface of the sea. At least one anchor is fixed by a cable to the bottom of the bag. The bag is filled mostly with water and partly by air, whereby at least part of the air filled portion extends above the surface of the sea. The flexibility and extensibility of the bag is such that in the presence of waves its vertical dimension increases or reduces, thereby impeding transmission of wave energy at and below the surface.

Abstract: A floating dock having individual dock sections pivotally interconnected by continuous metal hinge connectors to permit relative vertical pivoting movement between adjacent dock sections. The hinge connectors each comprise a pair of elongated metal hinge leafs pivotally interconnected by a pivot pin extending through aligned hinge loops on the hinge leafs. The hinge connectors are secured to adjoining spaced, parallel, portions of the respective dock sections with their pivot pins extending horizontally and lengthwise of the spacing therebetween and with the hinge leafs and their hinge loops bridging and closing the gap between the spaced dock sections at the level of their deck surfaces to form continuations thereof. The hinge leafs are preferably formed with depending side anchor leg portions for securing them to the dock sections, and their hinge loops are preferably located on their underside.

Abstract: Floating structures, for example, for recreational aquatic activities, comprises a plurality of individual uniquely-constructed modular flotation units constructed to permit any desired freeboard dimension and/or buoyancy characteristics.

Abstract: A float structure includes a flotation portion, a frame portion, a shell portion and a connector portion. The flotation portion includes a unitary porous slab member having a generally quadrangular configuration and includes upper and lower major faces and sidewalls joining same. The sidewalls taper inwardly toward the lower major face thereof. The frame portion includes a plurality of elongated interconnected strip members disposed around the periphery of the slab member adjacent the upper major face thereof. The shell portion includes a continuous waterproof covering over substantially the entire outer surface of the flotation portion. The connector portion includes a plurality of spaced fasteners extending through the shell portion into the frame portion and capable of securing bracket members to the periphery of the structure; whereby the float structure may be carried to a body of water and anchored therein at a desired location.

Abstract: An inflatable boom raising hose is sized such that the hose, upon inflation, raises the boom from the sea bed. The hose carries internally a chain which acts as a weight to drive the hose and boom to the sea bed, which takes up tensile forces and which prevents folds being formed in the boom raising hose as it sinks to the sea bed and which insures air passage therethrough, full evacuation of the air therefrom and complete collapse of the boom raising hose during evacuation of air therefrom at one or both ends thereof when the hose is deflated.

Abstract: A foldable, multi-hull pontoon suitable for use in bridging or as a ferry, has a sequence of trapezoidal hull plates (1) successively hinged to one another at their parallel edges so as to fold in concertina fashion, alternate pairs of the plates being mutually and transversely webbed at each end with collapsible triangular bulkheads (7) which define with the hull plates a series of triangular section hulls (13). Gunwale spacing beams (40) are provided to stabilise the opened pontoon and to provide trackways.

Abstract: A pontoon utilizing a container having a bottom portion and side portions which extend upwardly from the bottom. The top of the container is covered by a cap which may be moldable material, such as concrete. The cap is held to the container forming a pontoon.

Abstract: A buoyant plant especially for the off-shore manufacturing of concrete structures, as e.g. oil platforms, comprises two substantially parallel, spaced, elongated side sections 1,2, a roof sections 3 extending from the forward to the backward ends of said sections and connecting the top of said side sections to each other, a stem section connected to the forward ends of said side and roof sections, a substantially rectangular bottom section 5, the forward short side end of which is connected to said stem section and the backward short side end of which is situated spaced apart forwardly of the backward ends of said side sections, said bottom section being connected along its long side ends to the lower parts of said side sections, and a buoyant stern section 6 situated, and connectable and disconnectable, respectively, in the opening between said roof and side sections, said stern section 6 extending from the inner face of one side section to the other.

Abstract: A bouyant foundation comprising a substantially unitary concrete hull defined by bottom, side and end walls; at least one partial bulkhead wall disposed generally normal to and spanning the bottom wall and having a height less than that of the upstanding walls to yield a plurality of recessed flotation cavities bounded by flotation cavity side walls; generally rectilinear flotation block members, having reentrant sidewall portions, disposed within the flotation cavities; restraining wedge members integral with the flotation cavity sidewalls received within the reentrant portions of the flotation block members for fixedly retaining the same within the cavities, and a method for fabricating such a structure comprising the steps of establishing a construction form including bottom, side and end wall form members; depositing a concrete mixture on the form members to yield a substantially unitary hull including concrete bottom side and end walls; positioning a plurality of positive flotation members as internal bu

Abstract: A pontoon flotation device having forward and rearward ends and including at least two parallel pontoons fastened to a substantially rectangular deck panel. The deck panel has upturned side flanges extending the length of each side of the deck panel with a pontoon located parallel to and beneath each side of the deck panel. Each pontoon includes a substantially rectangular bottom panel and inner and outer upwardly extending side panels joined to opposite long edges of the bottom panel. The outer side panel extends upwardly beyond the furthest upward extension of the inner side panel to extend parallel and adjacent to a side flange of the deck panel. By this means, the deck panel and outer side panel of the pontoon are in position to be conveniently fastened to each other.

Abstract: A buoyant marine storage vessel for fluids, such as oil, includes a flexible containment bag having at least a controllable inlet and outlet for fluids and a wire rope cage for the bag which is attached to the bag in such a manner that emptying of the fluid content of the bag is enabled by the buoyant pressure of water in which the vessel is located. The vessel can be anchored at a desired location and may include a buoyant support and protective frame having sections articulated on two perpendicular axes. Clusters of vessels may be created for storing large volumes of fluid with economy.

Abstract: A semi-submersible offshore platform comprises an operating deck carried by four cylindrical columns supported by a pontoon structure comprising four-sided boxes formed into a square ring. Each pontoon box is subdivided into two compartments by a longitudinal centerline bulkhead, the compartments being further subdivided into tanks by transverse bulkheads. Tanks outside the centerline bulkheads are used for ballast water, and tanks inside the centerline bulkheads are used to store the oil produced.

Abstract: A pontoon assembly for floating bridges includes four pivotally interconnected articulable floats providing a pontoon assembly having a folded and an unfolded position. Each of the floats is generally rectangularly shaped. In the unfolded position the pontoon assembly has an inner two floats and an outer two floats and the outer two floats are lengthwise connected to an outer edge of the inner two floats. The inner two floats each have an upper surface which provides a vehicular roadway. A rectangular recess is disposed in each of the outer two floats and the recess has a size sufficient to permit a ramp part to be removably positioned in there. The ramp parts have a height corresponding to the depth of the recess in order to provide a flush upper surface with the upper surface of the associated outer float. Each of the ramp parts includes lugs to permit connection with an inner float to thereby provide a closed rampway.

Abstract: The present invention is a floating highway unit which has a structure which facilitates both removal from linkage in a series of units forming the highway, provides for simple alignment of the units during assembly, and also allows vertical movement caused by tides and waves. Protection is provided for the highway by use of a partly floating barrier, for damping wave motion, thus substantially reducing the amount of absolute and relative movement of the floating highway units. Each of the floating units of the present invention is comprised of a generally rectangular horizontal pontoon including provisions for floatation of the pontoon, the pontoon having a centrally located horizontal tongue extending outwardly from a short side of the pontoon whereby the top surface of the tongue is an extension of the top surface of the pontoon. A recess is located in the opposite side of the pontoon having a shape for enclosing the tongue which matches the shape of the tongue.

Abstract: A concrete marine float having a deck plate which is substantially wider than the width of the underlying casing in order to form overhanging flanges on opposite sides of the float. The flange is supported by longitudinally spaced gussets which extend from the sidewalls of the float to the underside of the deck. Utility conduits extending along the float beneath the flanges pass through the gussets and are thereby supported. The utility conduits pass upwardly through the deck to communicate with conventional utility outlets mounted on the deck.

Abstract: This floating boom comprises a flexible structure forming a barrier provided with transverse stiffeners to which are secured floats adapted to support this structure in a substantially vertical position in water. The stiffeners are designed so as to be resiliently bent at their lower part under the action of the water current for a velocity of the water current sufficient to cause bending without causing any substantial change in the inclination of the remainder of the boom in water.

Abstract: A transportable submerged breakwater is described. The breakwater includes a pair of vertical parallel concrete walls spaced apart from each other. The walls have floatation cells containing buoyant means. The walls have a density slightly less than that of sea water and float in a substantially submerged condition with a top horizontal wall edge at or slightly above the water surface. Rigid members space the walls and rigging means provide tension to hold the walls against the rigid members.

Abstract: The invention concerns the design of an oil containment boom suitable particularly for stowage on a reel. The boom in its inflated condition, is of "T" section having double buoyancy chambers and a central skirt member. The boom utilizes a tension wire in its lower skirt region and an air pressurizing hose in its upper skirt above the buoyancy chambers. The geometry of the panels making up the chambers is arranged, together with the joints, to give a substantially flat deflated form. The air pressurizing hose and the tension wire are of comparable diameter each being of larger diameter than the maximum thickness of the deflated boom whereby undesirable folding and puckering of the boom material when wound up is accommodated in the lateral space between the hose and the wire.

Abstract: A portable dock and dock sections used therewith, characterized by each of the dock sections have a plurality of frame members forming a rectangular deck frame for supporting a deck assembly, a pair of adjustable legs extending from adjacent one end of the rectangular deck frame and a first coupling unit disposed on a frame member at the other end of the deck frame. Preferably, an additional or second coupling unit, which is adapted to cooperate with a first coupling unit, is arranged either on an end or side frame member or both at the one end to enable connecting sections together to form either a straight line pier or a pier with a "T" or "L" shape. The portable dock also includes an anchor section having an anchor member with a similar coupling unit which coact with the first coupling unit of a first dock section for securing the first dock section to the beach or shoreline.

Abstract: A dock float construction for supporting dock planks, floating platforms, piers, dredge pipes and the like which is constructed of high strength plastic and buoyant foam material with or without a hollow center and having a sealing skin, each float module having a top edge recess or bench for vertical structural elements with transverse fastening rods anchored in the modules to join modules to functional units.

Abstract: A system for connecting a row of concrete marine floats to each other by fastening elongated wales along the upper side edges thereof. Post-tensioned tendons having fastening members mounted on their ends extend transversely through the float. The tendons are relatively thin so that their elongation responsive to tensioning is sufficient to maintain the force of the wales against the float as the wales shrink. However, the tendons, being relatively thin, do not have sufficient strength to withstand the shear forces generated between the float and wales. Consequently, rigid shear-reinforcing sleeves, preferably surrounding the tendons, project from the float into the wales. The tendons may be either rigid rods having threaded ends or flexible wire cables having an anchor mounted at each end.

Abstract: A marine float having a concrete casing surrounding a core of buoyant foam. The casing includes conventional side walls, end walls and a bottom along with a specially constructed deck. The deck includes at least one longitudinally extending utility trench which is easily accessible by removing a cover which is releasably secured to the deck. Elongated wales extend along the upper edges of the side walls, and tie rods loosely surrounded by through-tubes extend from one side wall to the other beneath the utility trench. The ends of the tie rods project through the wales, and fastening members are secured thereto thereby securing the wales to the casing and compressively loading the deck. Utility conduits positioned in the utility trench are connected to utility outlets mounted along the side edges of the deck by either transverse utility trenches or transversely extending tubular conduit embedded in the deck.

Abstract: A marine fender having high energy absorption capacity, low reaction force, a smooth exterior surface and no extensive exterior support structure to preclude snagging and reduce maintenance is provided. The fender comprises a resilient core having a cylindrical central portion tapering at each end to a truncated cone-shaped end portion, a fitting at each end of the core disposed coaxially with an axial bore in the core, flexible strength member in the axial bore interconnecting the fittings and providing means for adjustably biasing the fittings toward each other, and a flexible elastomeric skin enclosing the core and substantial portions of each fitting to protect the core from wear and abrasion and to distribute impact loads evenly over the core and fittings.

Abstract: The invention is directed to a lockable support float, preferably blow molded, for use in swimming pools and the like. It comprises at least first and second expanded members having mateable ends which are adapted to slide over and lock onto a rope. Each member includes an opening that is eccentrically positioned therethrough and alignable with each other for sliding engagement with a rope. Each member includes either a female or a male locking member comprising concentrically positioned annular groove and annular extension, respectively. The annular groove includes at least two projections which extend over a portion of the groove, and the annular extension includes a flange around the perimeter thereof for locking engagement with said projections. By rotation of the locked members the respective openings therethrough become offset with respect to each other and any rope positioned therethrough is securely locked in the openings of the float.

Abstract: A design of an oil containment boom suitable particularly for stowage on a reel. The boom, in its inflated condition, is of "T" section having double buoyancy chambers and a central skirt member. The boom utilizes a tension wire in its lower skirt region and an air pressurizing hose in its upper skirt region above the buoyancy chambers. The geometry of the panels making up the chambers is arranged, together with the joints, to give a substantially flat deflated form. The air pressurizing hose and the tension wire are of comparable diameter each being of larger diameter than the maximum thickness of the deflated boom whereby undesirable folding and puckering of the boom material when wound up is accommodated in the lateral space between the hose and the wire.

Abstract: An oil boom comprises a plurality of collapsible support members, particularly hinged polypropylene mouldings, detachably strung together, apparatus to hold said support members in the non collapsed state, and a sleeving of water-resistant oil-absorbent material, in particular a laminar pile surfaced thermoplastic material, disposed round the support members, the support members, when in the non collapsed state and bearing the sleeving, being capable of floating on the surface of water.

Abstract: A lightweight concrete float having a concrete shell surrounding either a hollow or buoyant foam core. The shell includes a deck surrounded by integrally formed, downwardly projecting side walls of sturdy but relatively heavy standard aggregate concrete and a bottom surrounded by integrally formed, upwardly projecting uniform or tapered side walls of lightweight but relatively weak foam aggregate concrete. Reinforcing rods are embedded along the edges of the deck, and a reinforcing mesh extends around the reinforcing rods and through the deck, side walls and bottom. The float may be formed by first pouring a layer of foam aggregate concrete into a form having a rectangular bottom surrounded by four sides. A block of buoyant foam is then placed on the bottom layer of concrete with the sides of the block spaced apart from the sides of the form. The space between the sides of the form and the sides of the block is partially filled with foam aggregate concrete.

Abstract: A floatation device to which a swimmer's suit may be secured for retrieval at a later time. The floatation device includes floatation apparatus and apparatus for attaching the bathing suit to the floatation apparatus. The apparatus for attaching the suit to the floatation device may include a spring biased clip, a hole provided in the floatation device, or a pair of narrowly separated fingers extending from the floatation apparatus. The floatation apparatus may be formed of a closed cell synthetic foam formed of a material such as polyethylene, or any other buoyant material.

Abstract: A plurality of relatively narrow finger piers project perpendicularly from mainwalk floats at spaced-apart locations. The finger piers are secured to the floats in cantilever fashion using a variety of fastening structures. Since loads carried by the finger pier are not supported by the buoyancy of the pier, the width and thickness of the pier can be substantially less than comparable floating finger piers. In one embodiment the pier is principally formed by a triangular frame which is secured to the mainwalk floats by either a mounting bracket or rods extending transversely through the mainwalk floats and longitudinally through upper corner pipes of the triangular frame. A deck is then fastened across the upper pipes. The vertical angle of each pier may be adjusted by rotating an adjusting nut which abuts the lower pipe of the triangular frame. In a second embodiment pairs of parallel beams are secured to the mainwalk floats by a bracket, and a deck is mounted on the upper surface of the beams.

Abstract: In a system for interconnecting buoyant float sections in an articulated manner, a receiver assembly for automatically engaging a connector of a type having a longitudinally inclined nose section and a pair of transverse locking grooves. The receiver assembly comprises a receiver housing with an interior channel, a U-shaped locking guillotine member and a locking assembly. The locking guillotine is slideably introduced into a transverse slot in the receiver housing; it rests on a pair of locking bars in the locking assembly with the legs of the locking guillotine extending part-way into the interior channel of the receiver assembly. As the connector is extended into the channel, the legs of the locking guillotine contact the inclined surface of the connector nose section, causing the locking guillotine to slide up within the slot until aligned with the connector locking grooves. The locking guillotine then falls, the guillotine legs sliding down within the locking grooves, to effect interengagement.

Abstract: A multipurpose floating structure comprises a large number of flotation units joined together in a regular reticulated pattern in one or more horizontal tiers, each flotation unit comprising: a square plate; a watertight can structure of inverted conical shape fixed at its base to the lower surface of the square plate; a vertical leg column fixed at its upper end to the vertex part of the can structure; a concrete weight disposed around and supported on the leg column; and connecting fittings for connecting the corners of the square plates of four adjacent flotation units at their common meeting point.

Abstract: A concrete float having a buoyant foam core surrounded by a concrete shell. The deck of the shell has integrally formed therewith a plurality of transverse ribs and longitudinal ribs which strengthen the deck. Consequently, the necessary strength for the deck can be achieved by utilizing a substantially reduced quantity of concrete. A tubular conduit extends beneath at least some of the transverse ribs. The conduits are provided in order to receive tie rods having their ends projecting from the sides of the float and through elongated wales which serve to secure the floats to each other. The concrete is preferably reinforced with conventional concrete reinforcing bars. The float is formed by placing a rectangular block of foam in a rectangular form after a layer of concrete has been poured in the form with the foam core being positioned apart from the sides of the form.

Abstract: A utility distribution system for a floating unit having a core and an envelope with a top portion utilizing a trench extending along a dimension of the top portion of the floating unit. The trench is formed by a wall being part of the envelope of the float unit. The system also includes means for permitting ingress to and egress from the trench for at least one utility conduit. The system also includes means for supporting the wall of the trench.

Abstract: A floating dock having a steel framework to the underside of which are fastened buoyant flotation bodies and to the upper surface of which is fastened a rigid imperforate sheet such as plywood. The framework is constructed of a suitable number of C-shaped structural members each of which has a uniform cross section and a uniform hole pattern therein. The hole pattern is established so that members of different lengths can be assembled to form a dock structure of virtually any shape and size. All parts of the floating dock are dimensioned so that joints between various members are staggered to provide high strength and rigidity. A method for fabricating the floating dock structure which makes possible at least partial construction before the dock structure is placed in the water and also makes possible construction by persons of moderate skill using conventional hand tools.

Abstract: A concrete float having a buoyant foam core surrounded by a concrete shell. The deck of the shell has integrally formed therewith a plurality of transverse ribs and longitudinal ribs which strengthen the deck. Consequently, the necessary strength for the deck can be achieved by utilizing a substantially reduced quantity of concrete. A tubular conduit extends beneath at least some of the transverse ribs. The conduits are provided in order to receive tie rods having their ends projecting from the sides of the float and through elongated wales which serve to secure the floats to each other. The concrete is preferably reinforced with conventional concrete reinforcing bars. The float is formed by placing a rectangular block of foam in a rectangular form after a layer of concrete has been poured in the form with the foam core being positioned apart from the sides of the form.

Abstract: A marine float having a concrete casing surrounding a core of buoyant foam. The casing includes conventional side walls, end walls and a bottom along a specially constructed deck. The deck includes at least one longitudinally extending utility trench which is easily accessible by removing a cover which is releasably secured to the deck. Elongated wales extend along the upper edges of the side walls, and tie rods loosely surrounded by through-tubes extend from one side wall to the other beneath the utility trench. The ends of the tie rods project through the wales, and fastening members are secured thereto thereby securing the wales to the casing and compressively loading the deck. Utility conduits positioned in the utility trench are connected to utility outlets mounted along the side edges of the deck by either transverse utility trenches or transversely extending tubular conduit embedded in the deck.