Stable efficient air lubricated ship

Details Stable efficient air lubricated ship Stable efficient air lubricated ship

2001-08-13

2003-08-26

Morano, S. Joseph (Department: 3617)

Ships

Building

Antifriction surfaces

C114S061100, C114S280000, C114S291000

Reexamination Certificate

active

06609472

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to the field of air lubricated boat or ship hulls used as means to increase the efficiencies of such hulls and to their propulsion and stabilization systems.
BACKGROUND OF THE INVENTION
The idea of placing a layer of air between the underside of a ship's hull and its supporting water surface has been around for many years. The Russians have reported some success with this concept.
FIGS. 25 through 32
of this application show some of the more recent thinking along the line for Air Lubricated Ship designs. These are normally referred to in the specifications herein as the ALS.
Further, applicant has realized some commercial success with his pressurized air supported boat designs. One of these is illustrated in U.S. Pat. No. 5,839,384. That patent illustrates a boat hull where the bow of the boat operates proximal the water surface. The pressurized air cushion in a cavity built into an underside of the boat's hull depresses the water surface going from the bow to the stern such that the stern is lower than the bow. The pressure in the air cushion is essentially constant over the entire area of the air cushion. Air cushioned boats of this general type are commonly known as Surface Effect Craft, or simply SES's, since they work on the water's surface.
There is a major difference between the ALS and the SES concepts. The forward portion of the ALS is below the water surface and creates a hole in the water. Proper location of a step in the hull and shaping of the aft sections of the hull of the ALS form a cavity when the ALS is moving forward. This effect can be realized by viewing the rising of the water behind a planing boat's hull until it reaches sea level.
An example of current thinking in ALS hull design can be seen in
FIGS. 27 and 31
and
32
of this application. Blower pressurized air is supplied to the cavity formed behind the step in the hull thereby creating a pressurized air layer between portions of the bottom of the ship and the supporting water surface. This, of course, reduces wetted area friction of the hull. It is to be noted that the air cavity rises going from aft of the step rearward until the water surface again contacts the hull. Efficiency gains for the ALS compared to a conventional hull are claimed to be in the twenty-percent area. Power to run the blower is very small with a rough estimate as five percent or less of propulsive power claimed.
By contrast, the SES is more of a surface-skimmer type vessel whereby a blower-pressurized air cushion disposed below the SES's hull supports a majority, normally about eighty percent, of vessel weight. The SES's bow is located proximal the water surface and the effect of the pressure in the air cushion is to depress the water level going from bow to stern. This makes for a very efficient vessel that requires only about half of the propulsive power of a comparable monohull or catamaran at high speeds. However, as size and weight of the SES increase the percentage of total power required to run the blower(s) increases rather dramatically. Roughly speaking, blower power requirements, given as a percentage of the propulsive power requirements, range from about ten percent for a 100 foot (30-meter) SES to more than fifty percent for a 656 foot (200-meter) SES. Larger size SES's have greater proportional blower power requirements. As a point to consider, a 100-foot (30-meter) SES would normally depress the water going from bow to stern by about two feet (0.61 meter) while a 656 foot (200-meter) SES would depress the water going from bow to stern by about 16 feet. That is eight times as much for the large SES.
In rough comparison: 1) The ALS gives about a twenty percent reduction in propulsive power requirements and needs about an additional five or less percent power for its blowers and 2) The SES generally gives about a fifty percent reduction in propulsive power requirements but needs from ten to over fifty percent additional power for its blowers. The SES clearly wins the overall efficiency battle for smaller sizes—say up to 350 feet (107 meters) or so. The ALS comes into primary contention for large hulls where its need for blower power of only about five or less percent of the value of its propulsive power overcomes its lower hull efficiency. A heavily loaded 656-foot (200-meter) SES would normally require on the order of fifty percent of its propulsive power to drive its blowers.
This instant application presents significant improvements to ALS technology as applied to all type and sizes of boats and ships but is primarily directed toward large ships. Some areas of advancement to the ALS concept offered by the instant invention include: 1) Means to extend the ALS's air cavity further forward, sometimes with multiple air cavities, and thereby further reduce hull wetted area friction, 2) Hydrofoil(s) disposed forward in the ALS's hull to both increase hull stability and to provide means to extend the air cushion further forward in the ALS's hull, 3) Propulsion systems particularly conceived and disposed to maximum their efficiency in ALS's, and 4) Means to stabilize the ALS by addition of outrigger hulls. The instant invention presents both single and multiple ALS hull configurations.
The instant invention offers advancements over applicant's earlier inventions as well as over the prior art. These advancements are discussed in some detail in the following sections.
Szpytman, U.S. Pat. No. 3,871,317; Dunajeff, U.S. Pat. No. 1,412,846; Meyer, Jr., U.S. Pat. No. 3,968,762; Tattersall, U.S. Pat. No. 4,166,515; Huang, U.S. Pat. No. 5,339,761; and Schlichthorst et al, U.S. Pat. No. 4,660,492 all present partially air cushion supported marine craft that also have hydrofoils. As air cushioned craft that utilize pressurized air to depress the water surface below their air cushions as seen going from the bow to the stern, these craft are known as Surface Effect Ships (SESs). None of these craft have hydrofoil members that emanate from either side of a lower part of the forward bow portion to thus form an enlarged substantially horizontal surface on the underside of the forward bow portion as compared to bow sections proximal to and above the hydrofoil as does the instant invention. The aforementioned substantially horizontal and wide under surface at the bow that is formed by the design and placement of the bow hydrofoil provides good ride qualities since the bow is deeply submerged and also provides a wide substantially horizontal surface that allows starting an air cushion proximal the bow. It is further to be noted that all of the aforementioned U.S. Patents are SES type pressurized air cushion designs that have their bows at or very close to the water surface. The pressure of the blower supplied air depresses the water surface going from forward to aft so that the water surface is substantially lower at the stern than at the bow. The instant invention is a true Air Lubricated Ship (ALS) since its bow is deeply submerged to actually dig a deep hole in the water. The water leaving the bow at the step that starts the air cushion(s) rises going aft. While not quite as efficient as a pure SES, the advantage of the instant invention's ALS concept is that a much lesser amount of blower pressurized air and hence blower power is required to supply the air layer(s).
SUMMARY OF THE INVENTION
The primary object of the instant invention is to offer a notable improvement in ALS efficiency by extending the pressurized air lubrication layer(s) further forward in the ALS's hull.
A related object of the invention is that the air or gas layers be pressurized by artificial means.
A directly related object of the invention is to provide a hydrofoil forward on the ALS that, due to its widening effect on lower portions of the ALS's hull, allows a step that defines the forward end of the first air lubrication layer to be moved further forward.
It is a related object of the invention that the a step be positioned at a forw

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