Ships – Building – Antifriction surfaces
Reexamination Certificate
1998-11-23
2001-03-13
Basinger, Sherman (Department: 3617)
Ships
Building
Antifriction surfaces
C114S061100, C114S273000, C114S282000
Reexamination Certificate
active
06199496
ABSTRACT:
FIELD OF THE INVENTION
The instant invention describes marine vehicles that operate in a surface effect condition by entrapping a cushion(s) of artifically pressurized gas between the vehicle and a water surface and/or a ram effect of ambient air that is sandwiched between the vehicle and a water or other surface at higher vehicle speeds. The first are most commonly called hovercraft or Surface Effect Ships (SES's) and the latter Wing in Ground Effect (WIG), Wing in Surface Effect Craft, or simply wingships. The common thread of all of these is that the pressurized gas disposed between the vehicle and the supporting medium carries most of vehicle weight. In any case, overall efficiencies of the SES are much greater than conventional marine vehicles and overall efficiencies of the WIG are much greater than commercial aircraft.
Applicant's earlier developments of marine vehicles using artifically pressurized supporting gas cushions have been successful and have resulted in a number of vehicles being built. What promises to be far superior to any of its predecessors is now called the SeaCoaster marine vehicle that uses multiple hulls with a long and slender air cushion in at least one of such hulls. The multiple hulls have very fine entry bows and divergence of their gas cushions back to a point where the sides of the gas cushions become parallel in the preferred embodiments. Applicant has conducted extensive model tests to establish allowable ranges of divergence of the gas cushions and has also devised an optional new knife type bow that is now referred to as the SeaSaber bow for its wave slicing abilities. The clearly defined low divergence angles of the bows are invaluable for rough sea operation of SeaCoaster. When coupled with the optional SeaSaber bow there are further advantages realized in some speed and sea conditions that makes SeaCoaster an exceptionally good sea boat.
de Pingon, French Patent 0271372 has catamaran-like sidehulls in a marine vehicle with pressurized air cushions under each sidehull; however, the entry of each of his sidehulls is rather blunt and the total divergence of his air cushion sides, as seen in a waterline plane of the hull, is very abrupt with total divergence angles of over 45 degrees. Applicant has established that such divergence angles will contribute to a totally unacceptable ride in rough seas. Applicant limits the total divergence angle of SeaCoaster's sidekeels to less than 26 degrees, with at least part of such divergence preferably on either side of a vertical longitudinal plane of the hull. A divergence angle closer to 18 degrees is optimum while under 20 degrees is set as a target for good rough sea ride qualities combined with enough divergence to obtain sufficient cushion area to properly support the vehicle. Some discussion is now in order regarding the relevance of the proper divergence angle of the sidekeels from the narrow bow going aft to where they become more parallel. This angle is referred to as the total divergence angle of the sidekeels. First, a rectangular gas cushion with a squared off front end and widely spaced substantially parallel sidehulls that are not joined by a narrow bow forward will actually be the most efficient in calm seas as that squared off bow arrangement has the largest gas cushion area and hence the lowest most efficient gas cushion pressure, the bow seal will actually be clear of the water at high speed resulting in minimum bow seal drag, and the sidekeels will be parallel over their entire length which is a least drag situation. However, such squared off bow seal designs have very poor rough sea performance.
Tests have been conducted on Applicant's narrow pointed bow designs with reduced sidekeel total divergence angles. Bow movement or pitching rough seas starts to fall into an acceptable range at just under 26 degrees total divergence angle. It is a compromise as to how far to lower the total divergence angle and still have sufficient gas cushion area to properly support the vessel. Tests with sidekeel divergence angles of just under 20 degrees showed a good compromise between rough sea ride qualities and sufficient cushion area. Therefore, the necessity limits of sidekeel divergence angle for the instant invention are less than 26 degrees with less than 20 degrees preferred. Note that these divergence angles are slightly greater than those noted in Applicant's earlier U.S. Pat. No. 5,611,294 that issued Mar. 18, 1997. This is because tests on a full size vehicle indicated that greater cushion areas are necessary to support heavy vehicle weights. This means that divergence angles must be increased and, indeed, divergence angles of greater than 26 degrees are considered to be within the scope of the instant invention so long as bow shapes forward of the start of the cushion(s) are relatively fine to insure good rough sea ride qualities.
SeaCoaster's optional SeaSaber bow knifes through waves and also gives a longer waterline length which is invaluable for this high speed marine vehicle. In its preferred embodiment, SeaCoaster combines the SeaSaber bow with a very fine entry bow which has total average divergence of its sidekeels of less than 20 degrees, a series of vertically high water friction reducing steps down the length of its hulls, and a unique retractable water stabilizer system. Any one of these features, taken individually or collectively, make the instant invention far superior to and widely separate it from de Pingon.
Wilson, U.S. Pat. 3,191,572; Gunther U.S. Pat. No. 3,473,503; and Crowley, U.S. Pat. 3,742,888 present multiple air cushion hulls. Wilson and Gunther do not have open bottomed recesses in their individual hulls but rather plates with air discharge holes drilled in them as can be seen in FIG. 7 of Gunther and FIG. 2 of Wilson. Further, Gunther does not have air cushion sidekeels on his sidehulls and neither Gunther nor Wilson have recess aft seals in their multiple hulls which is a critical part of the instant invention as such aft seals are required to maintain a pressurized air cushion. Yet another difference is that Wilson's water contacting sidekeels are parallel from their forwardmost portions and do not diverge as specified in the instant invention. Wilson has upwardly curved angled surfaces that become bows forward; however, they, very importantly, do not make water contact in a calm sea surface when the blowers are operating and his boat is traveling forward at high speeds. Crowley, in his closest concept as shown in his FIGS. 9 and 10, does not have individual boat shaped multiple hulls but rather simply multiple air cushions all having a common center bow. As such, neither Wilson, Gunther, nor Crowley have concepts that resemble applicant's instant SeaCoaster invention.
Distinctions are also noted from applicant's U.S. Pat. Nos. 5,176,095 and 5,415,120 that show a total gas cushion divergence angles of over 30 degrees and also from an article in the May 1992 issue of “Ship & Boat International” magazine that shows applicant's earlier concepts where gas cushion divergence angles of approximately 30 degrees are shown. Neither of these divergence angles are acceptable for tolerable seakeeping characteristics. Importantly also, neither applicant's earlier issued patent nor the “Ship & Boat International” article talk of the SeaSaber bow or water stabilizer systems that are preferred components of the instant invention's SeaCoaster hull concepts.
SeaCoaster offers attention to details including the optional use of a venturi positioned in an interconnecting duct that connects gas cushion recesses in separate multiple hulls. The benefit of such a venturi is that is restricts gas pressure pulses from traveling from one multiple hull's gas cushion to another and thereby helps insure a smooth bounce free ride. Freygang, U.S. Pat. No. 2,399,670, uses a venturi as part of an air induction system for inflating a life raft. It is only used when inflating the raft and does not in any way connect two separate
Basinger Sherman
Van Der Wall Robert J.
LandOfFree
Hybrid air cushion ground effect vehicle does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hybrid air cushion ground effect vehicle, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hybrid air cushion ground effect vehicle will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2465261