Floating wave attenuator

Details Floating wave attenuator Floating wave attenuator

2002-07-29

2004-04-06

Lee, Jong-Suk (James) (Department: 3673)

Hydraulic and earth engineering

Bank, shore, or bed protection

Wave or flow dissipation

C405S025000, C405S028000, C405S031000, C405S219000, C114S266000

Reexamination Certificate

active

06715958

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a novel floating wave attenuator. More particularly, this invention pertains to a novel design of floating wave attenuator which has a curved vertical wave attenuating wall section, a bottom vertical motion braking flange, and an air chamber for adjusting buoyancy.
BACKGROUND
Floating breakwaters have been used for many years. Historically, a professional paper entitled “On Floating Breakwaters” was authored by Joly as far back as 1905. Perhaps the first major application of floating breakwaters was by the British during the Second World War. The Bombardon and Phoenix floating breakwaters were designed for use in the Normandy invasion of 1944. Notably, both were destroyed in a major storm.
In 1971, the United States Navy made a survey of floating breakwater concepts. The Navy found 106 different concepts that were either under current study, had been studied in the past, were in use, or had been used in the past.
Later, in 1981, the U.S. Army Corps of Engineers made a literature study of the then state-of-the-art in floating breakwaters. Although previous studies recognized at least sixty different groupings of floating breakwater concepts, the Corps study reduced the groupings further through geometric and functional similarities to ten major types of floating breakwaters. These major groups are:
(1) pontoon
(2) sloping-float (inclined pontoon)
(3) scrap-tire
(4) A-frame
(5) tethered-float
(6) porous-wall
(7) pneumatic and hydraulic
(8) flexible-membrane
(9) turbulence-generator
(10) peak energy dispersion
Although these studies and reports appear to reference a large number of floating breakwater concepts and describe a number of prototype installations, the fact is that very few floating breakwater concepts have actually matured into a commercially available product.
General Breakwater Characteristics
Normally, one of two general physical principles can be used to explain the wave attenuating ability of a specific floating breakwater. The first is turbulence and the second is reflection.
The general characteristics of turbulence-type breakwaters are low draft, generally large width with respect to the wave size most effectively attenuated, and flexibility. The most obvious physical measurement of turbulence-generating breakwaters that directly relates to the effectiveness of this type of breakwater is its width. The width of a turbulence-type breakwater should generally be at least equal to 1.0 to 1.5 times the wave length of the design wave. More is better. It is normally not necessary for a turbulence-generating breakwater to be rigid, and in fact, most breakwaters are characterized by the flexibility of the entire breakwater system.
Perhaps the best well known turbulence-generating breakwater is the floating scrap-tire breakwater. It is made by connecting tires together and floating them with cubes of styrofoam. The floating scrap-tire breakwater attenuates waves through a loss of energy caused by the multiple openings and “traps” through which the water must pass to get to the lee side. Basically, the maze of channels exhausts the force of the wave on its way through the springs.
Another form of wave turbulence attenuation is caused by friction during the movement of water along the bottom of a large flat plate. This is how a large flat raft can be used to stop waves. The plate, or raft, must be somewhat rigid when used in this way, and must be very wide with respect to the design wave.
The second general mechanism used to stop waves is reflection. The best reflectors are probably bulkheads. When a wave hits a flat shoreline bulkhead, it is almost entirely reflected. A floating breakwater that uses reflection to stop waves must have characteristics similar to a shoreline bulkhead if it is to be as efficient. Reflective-type floating breakwaters do not need as much width as a turbulence-inducing-type floating breakwater. The key to the highly effective reflection characteristics of a shoreline bulkhead is the mass of earth behind the bulkhead which prevents the bulkhead from moving. Similarly, rigidity in the water is the key characteristic required of a floating breakwater that relies on reflection to stop waves. If the entire breakwater, or some component of the breakwater, is able to move significantly in the water, the wave attenuation capabilities of that reflective surface are greatly reduced.
A second characteristic required for effective operation of a reflective-type breakwater is depth penetration or draft. Without sufficient draft, much of the wave energy will pass below the breakwater and will rebuild waves on the lee of the breakwater. Thus, the two key criteria for effective operation of reflective-type breakwaters are rigidity, or lack of movement in the water, and depth penetration, or draft.
E. Douglas Sethness, Jr., President, Waveguard International, Austin, Tex., in an article entitled “A Survey of Commercially Available Floating Breakwaters”, described the floating breakwater products, known to the author, that are commercially available on a continuing basis in the United States and Canada. According to him, these commercially available floating breakwaters can be divided between the following two general categories:
Reflective-type United McGill Cylindrical Float
WAVEGUARD
Meeco Hanging Panel
Unifloat Caisson
Turbulence-Generation Wallbreak
Scrap-tire
American Docks Raft-type
The purpose of the Sethness article was to inform the marina or small boat harbor owner of the more important aspects of evaluating the use of a floating breakwater at a given site. The decision process that is presented in the article was intended to aid the owner or developer in understanding the location, engineering, expected performance, and risk/benefit analyses that should be an integral part of that evaluation.
According to Sethness, there is no substitute for properly understanding the breakwater site conditions. This first and most basic step is the one most generally glossed over in the process leading to the purchase of a floating breakwater system. A proper wind and wave analysis is crucial. Then, although there are generally understood requirements for marina construction, a set of specifications that defines the performance criteria for floating structures inside the marina must be developed. Understanding the structural and operational capabilities of the boats and marina facilities is extremely beneficial when defining the necessary performance characteristics of the breakwater. The third point that should be fully understood by a breakwater purchaser is the risk involved. A floating breakwater will not stop all of the waves, particularly freak waves. The proposed breakwater system should havesome understandable means of scaling itself to the design wave. One size breakwater does not fit all conditions.
In conclusion, the Sethness article states that floating breakwaters are a practical means of solving some of the problems faced by marina and small boat harbor owners when they are required to expand into less well protected waters. Floating breakwaters may be the only alternative available for wave protection in areas that are environmentally sensitive, where there are boundary or navigation constraints, or where the water is very deep. However, as with many other things, a floating breakwater will perform only as well as the input, in terms of investigationtime and engineering, that has preceded its installation.
A number of patents disclose various designs of floating breakwaters. These include the following:
Issue Date
U.S. Pat. No.
5,429,452
Jul. 4, 1995
5,304,005
Apr. 19, 1994
5,215,027
Jun. 1, 1993
5,192,161
Mar. 9, 1993
5,107,785
Apr. 28, 1992
4,693,631
Sep. 15, 1987
4,406,564
Sep. 27, 1983
4,098,086
Jul. 4, 1978
4,023,370
May 17, 1977
3,864,443
Feb. 4, 1975
Foreign Patent No.
GB 1559845
Jan. 30, 1980
FR 2271345
Jan. 16, 1976
JP 60191073
Sep. 28, 1985
JP 6305480
Nov. 1, 1994
JP 2289713
Nov. 29, 1990
JP 63138011
Jun. 10, 1988
SUMMARY OF INVENTION
The invention is directed to a floating wave attenuator co

Affiliated with

Also associated with

Rating

Floating wave attenuator does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Floating wave attenuator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Floating wave attenuator will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3231418