Ships – Displacement-type hull
Reexamination Certificate
2002-08-29
2004-03-02
Basinger, Sherman (Department: 3617)
Ships
Displacement-type hull
C114S061290, C114S06700A, C440S066000
Reexamination Certificate
active
06698370
ABSTRACT:
STATEMENT OF GOVERNMENT INTEREST
The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
BACKGROUND OF THE INVENTION
The present invention relates to the hydrodynamics of marine vessels, more particularly to adjuncts, appendages and auxiliary devices for affecting same.
A stern flap is an extension of the hull bottom surface which extends aft of the transom. It is a relatively small appendage (typically constructed so as to include internal metal bracing beams and external metal plate material) which is fitted to the ship's transom. Critical stern flap geometry parameters include: (i) chord length; (ii) span across the transom; and, (iii) an angle denoted as “trailing edge down” (TED), referenced to the local buttock slope (run) at the transom. The main purpose of a stern flap device is to reduce the shaft power required to propel a ship through the water, thereby reducing the engine's fuel consumption and increasing the ship's top speed and range. The hydrodynamically significant stern flap surface is its lower surface. In principle, a stern flap is coupled with a hull stern so that the hull bottom surface and the stern flap lower surface essentially represent a kind of surface continuum, thereby effectively altering the hydrodynamic character of the hull.
The application of stern flaps to large displacement vessels is a fairly recent innovation. The U.S. Navy has been investigating the use of stern flaps on many different hull types. The standard (traditional or conventional) stern flap is designed with parallel, linear (straight) leading and trailing edges for orientation of these linear edges perpendicular to the ship centerline. Stern flaps have now been proven by the U.S. Navy to reduce the requisite amount of propulsive power during navigation, with several concomitant advantages. Stern flaps: foster reductions in operating and life-cycle costs through fuel savings; increase both ship speed and range; decrease the amount of pollutants released by ships into the atmosphere; and, reduce propeller loading, cavitation, vibration and noise tendencies.
Incorporated herein by reference is the following United States patent which is pertinent to stern flaps: Karafiath et al. U.S. Pat. No. 6,038,995 issued Mar. 21, 2000, entitled “Combined Wedge-Flap for Improved Ship Powering.” The following papers, each of which is incorporated herein by reference, are also pertinent to stern flaps: Karafiath, G., D. S. Cusanelli, and C. W. Lin, “Stern Wedges and Stern Flaps for Improved Powering —U.S. Navy Experience,” 1999 SNAME Annual Meeting (paper), Baltimore, Md. (September 1999); Cusanelli, D. S., “Stern Flaps—A Chronicle of Success at Sea (1989-2002),” SNAME Innovations in Marine Transportation, Pacific Grove, Calif. (May 2002); Cave, W. L., and D. S. Cusanelli, “Effect of Stern Flaps on Powering Performance of the FFG-7 Class,” SNAME Chesapeake Sect Paper, (October 1989); Cusanelli, D. S., and W. L. Cave, “Effect of Stern Flaps on Powering Performance of the FFG-7 Class,” Marine Technology, Vol. 30, No. 1, pp 39-50, (January 1993); Cusanelli, D. S., and K. M. Forgach, “Stern Flaps for Enhanced Powering Performance,” Proceedings of 24th ATTC, College Station, Tex. (November 1995); Cusanelli, D. S., “Stern Flap Powering Performance on the PC 1 Class Patrol Coastal, Full Scale Trials and Model Experiments,” PATROL '96 Conference Proceedings, New Orleans, La., (December 1996); Cusanelli, D. S., “Integrated Wedge-Flap, an Energy Saving Device,” 21st UJNR Marine Facilities Panel Meeting, Tokyo, Japan (May 1997); Cusanelli, D. S., and G. Karafiath, “Integrated Wedge-Flap for Enhanced Powering Performance,” FAST '97, Fourth International Conference on Fast Sea Transportation, Sydney, Australia, (July 1997); Cusanelli, D. S., “Stern Flap Installations on Three U.S. Navy Ships,” ASNE 1998 Symposium—21st Century Combatant Technology, Biloxi, Miss. (January 1998); Cusanelli, D. S. and L. Hundley, “Stern Flap Powering Performance on a SPRUANCE Class Destroyer, Full Scale Trials and Model Experiments,” Research to Reality in Ship Systems Engineering Symposium, Tysons Corner, Va. (September 1998); Cusanelli, D. S. and L. Hundley, “Stern Flap Powering Performance on a SPRUANCE Class Destroyer, Full Scale Trials and Model Experiments,” Naval Engineers Journal, Vol. 111, No. 2 (March 1999); Cusanelli, D. S., S. D. Jessup and S. Gowing, “Exploring Hydrodynamic Enhancements to the USS Arleigh Burke (DDG
51
),” FAST '99, Fifth International Conference on Fast Sea Transportation, Seattle, Wash. (August 1999); Cusanelli, D. S., and G. Karafiath, “Energy Savings and Environmental Benefits of Stern Flaps on Navy Ships,” ASNE Symposium: Marine Environmental Stewardship for the 21st Century, Arlington, Va. (October 1999); Cusanelli, D. S., and G. Karafiath, “Stern Flaps on Navy Ships, Fuel Savings and Environmental Benefits,” IMT'99, Innovations in Marine Technology, New Orleans, La. (December 1999); Cusanelli, D. S., “Stern Flaps and Bow Bulbs for Existing Vessels—Reducing Shipboard Fuel Consumption and Emissions,” United Nations Environmental Programme (UNEP 2001), Brussels, Belgium (February 2001); Cusanelli, D. S., and G. Karafiath, “Stern Flaps”, Professional Boat Builder Magazine, pages 81-87, (April/May 2001); Karafiath, G, D. S. Cusanelli, S. D. Jessup and C. D. Barry, “Hydrodynamic Efficiency Improvements to the USCG 110 Ft. WPB Island Class Patrol Boats,” 2001 SNAME Annual Meeting Paper, Orlando, Fla. (October 2001).
“Amphibious” U.S. Navy assault ships, designated “L_” ships (e.g., LHA, LSD, LHD, etc.), are primary landing ships that resemble small aircraft carriers. These amphibious ships contain massive well decks (which are accessed through one or more large folding stern gates), and are designed for putting troops on hostile shores. The present inventor was tasked to apply existing stern flap technology to “amphibious” U.S. Navy ships of the “L_” classes such as the WASP (LHD 1) Class, the WHIDBEY ISLAND (LSD 41) Class, or the HARPER'S FERRY (LSD 49) Class, wherein the hull design includes a large stern gate along with stern gate support structure (including plural support brackets) at least partially submerged aft of the transom.
The stern gate of an LHD class amphibious assault ship is typically designed to be mechanically pivotable about an axis situated in the lower part of the stern and above the waterline, thereby “opening” rotatingly downward-aftward and “closing” rotatingly upward-forward. A sizable structural unit is attached to the ship transom to support the stern gate in its fully opened position. This stern gate support structure generally includes main support brackets, smaller bracing supports, and a large diameter protection pipe defining its perimeter. When fully closed, the stern gate is positioned in an approximately vertical position; when fully open, the stern gate is positioned in an approximately horizontal or slightly downward from horizontal position so that the lower surface of the stern gate suitably rests upon the upper surfaces of the support brackets.
Prior to the present invention, U.S. Navy investigators believed that the presence of the stern gate support structure precluded the design of shallower angled stern flaps. However, the Navy investigators perceived as a benefit a “masking” effect associated with installation of a stern flap beneath the stern gate support structure. “Masking” of the stern gate support structure involved the effect of deflecting fluid flow away from the potentially high resistance components of the stern gate support structure. It was previously thought by U.S. Navy investigators that this kind of flap-underneath configuration would maximize the reduction of possible ship resistance (drag), due to the masking of the submerged stern gate support structure. Nevertheless, it eventually became apparent to U.S. Navy investigators that this masking effect (i.e.
Basinger Sherman
Kaiser Howard
The United States of America as represented by the Secretary of
LandOfFree
Hydrodynamic and supportive structure for gated ship stern does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hydrodynamic and supportive structure for gated ship stern, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydrodynamic and supportive structure for gated ship stern will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3285761