Pneumatic system reducing friction between a vessel hull and the surrounding water
A pneumatic system designed to minimize the high coefficient of water friction, known in the nautical industry as “skin resistance” or “drag,” against the submerged hull (10) area of a vessel. This system directs pressurized air from a shipboard compressor (30) through many distributing pipes (60). These distributing pipes (60) are arranged longitudinally and are evenly spaced transversely, adjacent to the internal hull (10) section that lies below the waterline. A plurality of smaller ejection pipes (70) project from the distributing pipes (60). Calibrated nozzles (80) connect the ejection pipes (70) to the vessel's exterior, releasing a constant flow of pressurized air as bubbles between the water (A) and the hull (10) surface. This layer of bubbles reduces the undesired effect of skin resistance (drag) caused by the viscosity of the medium through which the vessel navigates.
Jun. 30, 2006 [AR] Argentina No. 20060102831
FEDERALLY SPONSORED RESEARCHNot applicable.
SEQUENCE LISTING OR PROGRAMNot applicable.
BACKGROUND OF THE INVENTION1. Field of Invention
This invention generally relates to marine vessels, specifically to a system to increase a marine vessel's efficiency by using air bubbles under the hull to reduce friction or drag.
2. Prior Art
Previously, in an attempt to overcome the effects of friction between vessel hull and water, designs have included vessels such as the hovercraft (such as one described in U.S. Pat. No. 7,032,698 to Lee, et. al., Apr. 25, 2006), which is a watercraft that traps a generated cushion of air, and moves upon that air. In some cases, the air cushion acts as a means of propulsion. The hovercraft's hull glides over this air cushion, which has a lower friction coefficient than water. However, the functionality of this technique is restricted to relatively small vessels, because it demands a large quantity of highly compressed air, which, in turn, requires a high power compressor, thus making it impractical for larger vessels.
Some inventions seeking to exploit the low-drag property of air bubbles under a hull have incorporated components unnecessary to achieve the ultimate purpose. For example, the invention claimed in U.S. Pat. No. 5,967,071 to Wipper, Oct. 19, 1999, required a means to recover the expelled air, a means to separate water from the recovered air, and a recycling means to return the recovered air to the distribution system. Each additional means requires additional energy input, resulting in loss of the energy advantage gained by reducing the drag imposed by the water, which compromises the practicality of such an invention.
Another invention presented in U.S. Pat. No. 4,926,771 to Hull, May 22, 1990, consists of a ship hull with two keels forming a channel in between them. A shipboard compressor provides air through large diameter pipes. The air flows through the channel. This system, however, has the disadvantage of having a large volume of air requiring considerable energy, and thus, its use in small vessels is impractical. Furthermore, the efficiency of this system is limited to its effect in the channel, and has no measurable effect on the sides of the hull. It thus results in low efficiency.
Some inventions have attempted to lubricate the hull surface with substances other than pure air. For example, U.S. Pat. No. 5,456,201 Oct. 10, 1995, and U.S. Pat. No. 5,524,568, Jun. 11, 1996, both to Bobst, or U.S. Pat. No. 5,575,232 to Kato, et. al., Nov. 19, 1996, describes the use of a layer of air bubbles intermixed with water. However, water has a much higher friction coefficient than water. Consequently, the lubrication layer will be less effective at reducing drag if a high viscosity substance is present. The introduction of water to the lubrication layer impedes the advantages provided by water's low friction coefficient. This short-coming can be circumvented by requiring that the lubricating layer be made exclusively of air.
Previous inventions are less energy-efficient, because the air-producing portions of the hull do not remain submerged. To illustrate, U.S. Pat. No. 5,967,071, mentioned above, releases air from the bow, such that the air bubbles will drift astern. With faster watercraft, such as speedboats, it is well known that increased speed lifts the bow above the water's surface. Therefore, air bubbles could not be released to areas of the hull that remains submerged. Faster watercraft would benefit from air release areas at, or near the stern.
OBJECTS AND ADVANTAGESIt is widely known that water has a much higher viscosity than air. Thus, in water, friction produces a significant resistance to a vessel's hull as it navigates through water (known in nautical terms as “hull skin resistance” or “drag”). This opposition to the vessel's propulsion is the primary cause of fuel consumption; air resistance upon the vessel's remaining surface consumes one hundred times less fuel.
Due to significant drag, a hull's design is of great importance, particularly concerning the keel's capacity to dynamically penetrate the water. However, hull design alone does not completely solve the problem, because it will not reduce the lateral and underside surface area of the hull, which is still subject to the water's friction. This problem is magnified in large cargo vessels, because their hull design is limited by the need for interior holding capacity and their stability.
Accordingly, several objects and advantages of the invention are that it reduces the resistance or drag upon the skin of a vessel's hull. The object of this invention is to present a pneumatic system that constantly delivers pressurized air through pipes and calibrated nozzles, which are homogeneously distributed along the submerged exterior of a vessel's hull. As the air leaves the nozzles, it dissipates as small bubbles, which form a layer of lubricating micro-spheres between the hull and the water.
Another object is to optimize air output while preventing deterioration of the pipes delivering the air due to the constant high-pressure stresses.
In addition, another object is to minimize excessive waste of compressed air, which can be economically costly.
It is a further object is to provide a pneumatic system for friction reduction to high speed crafts, such as those used in nautical competition. In those cases, the bow's elevation results in a smaller portion of the hull remaining underwater.
Further objects and advantages will become apparent from a consideration of the ensuing description and drawings.
SUMMARYIn accordance with the invention, a pneumatic system of pipes delivers compressed air to the layer of water adjacent to a vessel's hull to reduce friction between the water and the hull. The system includes an onboard compressor connected to distribution pipes. Smaller ejection pipes deliver the compressed air from the distribution pipes to calibrated nozzles, which penetrate through to the exterior of the hull. The compressed air forms bubbles along the underside of the hull as the vessel travels through water. The layer of air reduces the friction between the hull and the water, thus increasing the vessel's efficiency.
DRAWINGS Figures
- 10—hull
- 20—engine room
- 30—compressor
- 40—pressure-regulating valve
- 50—manifold
- 60—distributing pipe
- 70—ejection pipe
- 80—nozzle
- A—water
- S—direction of vessel travel
In the following, preferred embodiments will be presented with reference to
As seen in
Similarly,
Accordingly, the reader will see that, according to the invention, I have provided a simple, efficient system to reduce water friction upon a vessel hull.
While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but as exemplifications of the presently preferred embodiments thereof. Many other ramifications and variations are possible within the teachings of the invention.
Thus, the scope of the invention should be determined by the appended claims and their legal equivalents, and not by the examples given.
Claims
1. A pneumatic system to deliver compressed air to water adjacent to a vessel's hull whereby friction between the water and said hull is reduced, comprising:
- A. an onboard compressor,
- B. a web of distribution pipes connected to said compressor, said distribution pipes arranged longitudinally along the interior of the submerged portion of said vessel's bulkhead,
- C. a plurality of ejecting pipes, smaller than the distribution pipes, and connected to said distribution pipes,
- D. a calibrated nozzle at the distal end of each of said ejecting pipes, said calibrated nozzles penetrating the hull's exterior surface, with said nozzles homogeneously distributed along the hull's exterior surface to expel into the water to form bubbles.
2. The pneumatic system of claim 1, further including a compressor powered by a motor driven by the vessel.
3. The pneumatic system of claim 1, further including a compressor powered by the vessel's engine.
4. A pneumatic system according to any one of claims 1, 2, or 3, wherein said compressor has a pressure control valve.
5. The pneumatic system of claim 4, further including the portion of the vessel's hull found below the waterline.
Type: Application
Filed: Jun 29, 2007
Publication Date: Apr 10, 2008
Inventor: Raul Iglesias Schoo (Buenos Aires)
Application Number: 11/824,273
International Classification: B63B 1/38 (20060101);