A floating dock is a very common method to secure a boat and gain access to it. People can readily embark and disembark the boat or ship tied alongside the dock. In the prior art, a floating dock is typically connected to either pilings, cables with manual adjusting winch or cables with counter weights to secure it in place. Otherwise, the dock would drift away.
A piling is a pole similar to a telephone pole, or it may be made of steel or concrete. Pilings are driven vertically into the floor of a body of water. The pilings are of sufficient length to extend above the surface of the water. The dock floats on the water, and is connected to the pilings by retaining rings that reside in the floating dock or is fixed to lengths of cables or chains that are of sufficient length to permit the dock to rise and fall with changes in water level due to, for example, high and low tides. The fixed cable or chain type can be adjusted by either a manually adjusted winch or with the use of counter weights.
If cables or chains are used instead of pilings, the sea anchors are placed on the floor of the body of water. The dock floats on the water, and in the prior art is connected to the sea anchors by fixed lengths of cables or chains as described above.
The prior art method of mooring a floating dock in place engenders several disadvantages. The connecting cables or chains are of a fixed length, and must be long enough to accommodate the maximum anticipated change in water level and/or require regular manual adjustment to remove the cable slack.
When the water is not at its maximum level, there is a significant amount of slack in the cables or chains. This allows even relatively minor perturbations, such as the wake of a passing boat, to cause the dock to move significantly up and down and also side to side, making the dock unstable. There is also no dampening of the dock's motion beyond the natural dampening of the water itself, so the dock will move for a long period of time, and will continue to move until the water stops moving. It is difficult to stand or move about on a dock that is simultaneously moving in various directions, and objects and supplies placed on the dock are also caused to move around unexpectedly.
Furthermore, the slack in the cables or chains allows the dock to drift horizontally from its original position, due to forces acting on the dock from wind, waves, and changing tide. A drifting dock poses a concern to adjacent docks and boats. Also, the dock will drift to the point where at least one of the cables or chains is taut, placing a significant stress load on the fittings to which the cable or chain is attached, or on the fittings and hinges connecting the dock to the dock ramp. This could lead to failure of a fitting, creating a need for immediate repair.
In addition, depending on the placement of the pilings or weights, the cables or chains connected to them from the dock may extend into areas where they create a hazard for individuals and/or boats. For example, a cable running underneath the water beyond the edge of the dock could be hit by someone diving or swimming, or could be hooked by the outboard drive gear of a passing boat.
The use of pilings introduces additional disadvantages that are not present if weights are used. The pilings disturb the floor of the body of water when they are driven through and into it. If telephone poles are used, the creosote, oil or tar present in the pole will leach into the water. Concrete will also leach into the water. The leaching contributes to water pollution, and also may cause deterioration of the pilings to the point where eventually they require replacement. Pilings are expensive, and therefore the initial cost of a dock that utilizes them is high. Should replacement of the pilings be required, the lifetime cost of the dock is even more substantial. Finally, the pilings protruding from the water may be unsightly, especially if they are not periodically cleaned. Furthermore, pilings greatly loose their effectiveness in water depths beyond 25' because of excessive bending or flexing.
Thus, there is a need for an apparatus that avoids the problems described above while addressing the concerns associated with prior art methods for mooring a floating dock. It would be highly preferable if such an apparatus allows vertical movement of the dock corresponding to changes in water level. Such an apparatus should also prevent the dock from drifting from its original position, and would compensate for lateral forces on the dock due to wind, waves, and currents. It would also be highly preferable if the apparatus actively dampens dock motion so as to maintain a stable surface and quickly return the dock to its initial ("neutral") position. In addition, it would be highly preferable because the apparatus eliminates the need for pilings.
Accordingly, it is the object of the present invention to allow sufficient vertical movement of a floating dock to account for changes in water level, either shorter term changes such as waves or longer term changes such as tide. In addition, it is the object of the present invention to maintain the dock in its original horizontal position, by applying sufficient pulling force on the connecting cables so that there is no slack in the cables, and by compensating for lateral forces on the dock. It is also the object of the present invention to quickly dampen dock motion to maintain a stable surface and return the dock to its neutral position.
Furthermore, it is the object of the present invention to provide a cost-effective and environmentally sound design that eliminates the need for pilings. Finally, it is the object of the present invention to be safe, compact and durable, and compatible with current floating docks.