Marine dock and flotation tank

A floating dock comprising a pair of flotation tanks arranged in parallel side-by-side relation, a plurality of transverse, equispaced double-saddle brackets having a pair of spaced-apart saddles each adapted to receive a flotation tank straddling said tanks along the length of the tanks, and connector means adapted to partially encircle each tank and to seat in a recess between corrugations extending from each saddle for connecting the tanks to the saddle brackets. The flotation tank comprises a cylindrical smooth inner wall and a corrugated outer wall coextensive and concentric with said inner wall defining a plurality of equispaced peripheral annular flotation cells extending along the inner cylindrical wall, and a closure plate at each end of the cylindrical walls connected to the inner and outer walls in a water-tight relationship defining a central flotation cell. The outer corrugated wall has a plurality of peripheral recesses extending circumferentially around said outer wall along the length of the outer wall. The floating dock has longitudinal side planks and a top deck, preferably a wood deck extending between and attached to the longitudinal side planks. The floating dock additionally may include one or more floating finger docks connected to a side of the floating dock perpendicular or parallel thereto.

BACKGROUND OF THE INVENTION 
(i) Field of The Invention 
This invention relates to a floating marine dock and, more particularly, 
relates to a novel flotation tank and tank assembly system for use in a 
floating dock. 
(ii) Description of the Related Art 
Shorelines subjected to tides, spring flooding and large waves require 
floating docks to allow compensation for changes in water level. The 
floating docks often are attached to the shore by a vertically pivotal 
ramp which allows the docks to rise and fall as the water level changes. 
Conventional floating docks, well known in the art, typically comprise a 
wood or steel frame with wood decking and flotation units housed in the 
frame beneath the decking. Typical floating units are rectangular, 
close-celled foam slabs such as rigid styrofoam, steel or plastic drums, 
and molded rectangular plastic compartments. Foam slabs are difficult to 
attach to the dock frame and often are detached and lost during storms, or 
are destroyed by muskrats and the like water dwelling rodents who bore 
into the foam to make nests. Drums also can be difficult to attach, and if 
perforated by rust or by impact with a sharp object, will be flooded, lose 
their buoyancy and sink. Molded plastic compartments are expensive to form 
and, if punctured, will be flooded and sink. 
It a principal object of the present invention to provide an inexpensive 
plastic flotation tank which can be manufactured in any desired length and 
diameter and which can be readily and securely attached to a deck frame. 
It is another important object of the present invention to provide a 
flotation tank which has a plurality of peripheral flotation cells which 
surround and protect a central flotation cell. A further object of the 
invention is the provision of a floating marine dock system which can be 
readily modified into a variety of finger dock configurations. These and 
other objects of the invention, and the manner in which they can be 
attained, will become apparent as the description proceeds. 
SUMMARY OF INVENTION 
In its broad aspect, the flotation tank of the invention comprises a 
cylindrical smooth inner wall and a corrugated outer wall coextensive and 
concentric with said inner wall defining a plurality of equispaced 
peripheral annular flotation cells extending along the inner cylindrical 
wall, and a closure plate at each end of the cylindrical walls connected 
to the inner and outer walls in a water-tight relationship defining a 
central flotation cell. The outer corrugated wall has a plurality of 
peripheral recesses extending circumferentially around said outer wall 
along the length of the outer wall. In a preferred aspect of the 
invention, the floating dock comprises a pair of said flotation tanks 
arranged in parallel side-by-side relation, a plurality of transverse, 
equispaced double-saddle brackets having a pair of spaced-apart saddles 
each adapted to receive a flotation tank straddling said tanks along the 
length of the tanks, and connector means adapted to partially encircle 
each tank and to seat in a recess between corrugations extending from each 
saddle for connecting the tanks to the saddle brackets. Each connector 
means comprises a semi-circular rod having threaded ends, said rods having 
a diameter substantially equal to the diameter of the outer wall 
circumferential recesses for seating in said recesses, and a nut threaded 
onto each end of the rod for removably securing each end of the rod to a 
saddle. Each saddle bracket has a top horizontal support member and 
vertical opposite side support members for receiving longitudinal side 
planks and a top deck, preferably a wood deck extending between and 
attached to the longitudinal side planks. 
In accordance with another aspect of the invention, the floating dock 
additionally comprises 
a floating finger dock, said floating finger dock comprising an elongated 
flotation tank, 
a plurality of single saddle brackets equispaced along said tank, means for 
securing said saddle brackets to the elongated tank, each saddle bracket 
having 
a top horizontal support member and vertical opposite side support members 
for receiving longitudinal side planks and a top deck, and means for 
connecting said finger dock to a side of the floating dock perpendicular 
or parallel thereto.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
With reference first to FIGS. 1, 2 and 3 of the drawings, the dock system 
of the present invention comprises a main dock 10 consisting of one or a 
plurality of modular sections 12 joined end to end. Each modular dock 
section 12 comprises a pair of parallel elongated flotation tanks 14 about 
18 inches in diameter and about 15 feet long secured a spaced distance 
apart along their lengths by equispaced double saddle brackets 16 which 
straddle said tanks and are connected thereto. Each adjacent pair of 
double saddle brackets 16 is inter-connected at about 5 foot intervals 
along each side of the dock by a pair of longitudinally extending side 
wood planks 17, 18 secured to the saddle brackets by bolts 19. A deck 20, 
shown on one half only of main dock section 12 in FIG. 1 for clarity of 
description, is comprised of transverse wood planks 21 secured to 
longitudinal wood side planks 17. 
Elongated finger docks 24 each comprise a single flotation tank 14 having a 
plurality of equispaced single saddle brackets 22 secured along its length 
for support of a deck 25 and is joined to main dock 10 by brackets 26, 27 
to be described. 
With particular reference now to FIGS. 2 and 3, each double saddle bracket 
16 comprises an upper transverse tubular member 30 positioned over a pair 
of spaced apart semi-circular saddles 32, 34 having a diameter suitable to 
mate with and engage the outside diameter of tanks 14. Saddles 32,34 are 
formed from stiff 1/4-inch thick 8 inch wide elongated steel plates 35 and 
are secured such as by welds to the transverse top member 30 by vertical 
and diagonal radial tubular struts 36, 38, and at each end by vertical 
flange plates 40. Transverse, equispaced wooden planks 21 are bolted or 
nailed to longitudinal side planks 17 to form an upper deck 20. 
Each tank 14 is connected to the underside of brackets 16 in a saddle 32 or 
34 by semi-circular steel rods 44 that are threaded at each end and are 
secured by nuts 45 to bracket plate 35. The steel rods 44 are seated in 
the hollows of the corrugations of the tanks to securely lock the tanks in 
place to prevent axial movement. 
Turning now to FIG. 4, each tank 14 is double walled and comprises a 
generally cylindrical corrugated outer wall 50 having circumferential 
peripheral recesses 52 formed between corrugations 54. A smooth 
cylindrical inner wall 56 is joined to the corrugated outer wall 50 at 
each of the recesses 52 by fuse welds formed during extrusion and vacuum 
molding of the composite tank wall. An end plate 58 is welded by weld 60 
continuously about the perimeter of plate 58 to each end of the outer pipe 
wall 50 to form a water-tight tank. 
Each flotation tank 14 comprises a central main flotation cell 62 and a 
multiplicity of secondary, isolated equispaced peripheral flotation cells 
64 along its length defined between inner wall 56 and each corrugation 54. 
Each tank thus has double-walled peripheral protection with independent 
isolated flotation cells 64 formed around the tank perimeter to protect 
against puncture while providing reserve flotation. Turning now to the 
embodiment of FIG. 5, in which the wood side members and decking are 
removed to show the sub-structure, flotation tanks 14 are shown arranged 
in parallel, side-by-side relationship to form main dock 10 with a pair of 
spaced-apart double-saddle brackets 16 inter-connecting a pair of tanks 
14. A first embodiment of finger dock 20, having tank 14a without upper 
decking, is shown connected to a main dock 10 by a T-bracket 70 having a 
transverse member 72 which is pinned at each end by bolts 74 passing 
through flanges 75 of brackets 16. A pair of diagonal links 76 connected 
to annular single saddle brackets 78 position the end of finger dock 20 
from dock 10. Diagonal links 80 connected to transverse link 72 adjacent 
the main dock at the one and attached to single saddle connector bracket 
82 at the other end anchor the finger dock 20 perpendicular to main dock. 
A second embodiment 86 of finger dock is shown in FIG. 5 wherein an 
extended link 88 positions the finger dock 86 parallel to the main dock 
10, link 88 being connected at one end to transverse frame 72 and 
connected at the other end to double saddle bracket 16 at 90. 
The present invention provides a number of important advantages. Each 
flotation tank can be formed by extrusion of a plastics materials such as 
polyethylene used for corrugated pipe in any desired diameter produced for 
pipe and cut to a suitable length. Although the description has proceeded 
with reference to 18-inch diameter tanks 15 feet in length, it will be 
understood that the diameter of the tanks can vary from 12 inches to 48 
inches and larger and the length of the tanks can range from 8 to 25 feet 
and longer. A closure end plate can be easily welded on to both ends of 
each pipe section to form a main flotation cell section. A plurality of 
equispaced secondary peripheral cells which are isolated from the central 
main flotation cell are provided by the corrugations to provide protection 
to the main flotation cell while affording secondary flotation. The tanks 
can be easily incorporated into a dock structure which in turn can be 
configured into a variety of shapes and sizes. 
It will be understood, of course, that modifications can be made in the 
embodiments of the invention illustrated and described herein without 
departing from the scope and purview of the invention as defined by the 
appended claims.