USA As Represented by Secretary of the Navy

Dominic S Cusanelli

Gabor Karafiath

Young T Shen

Jeffrey A Bradel

Steven Fisher

Andrew J Nowakowski

Chengwen Lin

Richard C Bishop

The invention is directed to an integrated stern bulb and flap for a water vessel, more particularly, a bulb having a main body section and a forebody section, the bulb positioned between first and second flap portions. The integrated stern bulb and flap provides improved power efficiency by reducing resistance at high speeds. The bulb of the integrated stern bulb and flap may be hollow, the interior being stowage space adding to the payload of the water vessel.

Integrated stern bulb and flap

A stern flap has a &ldquo;contour&rdquo; shape which facilitates installation thereof upon the curved stern of a ship. The stem flap's lower surface includes an intermediate region and two curvedly tapered end regions. The intermediate region is delineated forwardly by a curved leading edge and aftly by a parallelly curved trailing edge, the chord length therebetween being constant. The curve characterizing the flap's leading edge is congruent with the curve characterizing the ship stern's lower transverse edge (the junction between the ship's bottom and the ship's stern), thereby permitting contiguous disposition of the flap's leading edge relative to the ship's lower transverse edge, as well as permitting even and unbroken disposition of the flap's lower surface relative to the ship's bottom. The contour stem flap &ldquo;fits&rdquo; the ship's stern, thus lending itself to a hydrodynamically propitious mode of attachment whereby hydrodynamic efficiency is uncompromised.

Contour stern flap

Corrective stabilizing motions are applied to a sea vessel hull during seawater travel in response to stern flap displacement by hydrodynamic forces induced at the buttock of the vessel hull and by the lower flap surfaces at the stern end of the sea vessel hull in response to angular displacement of flap elements from a deployed position in either in-phase or out-of-phase relation to each other in rough seas. An angle of attack range for limiting angular displacement of the flaps is selected so as to minimize resistance to travel and optimize fuel saving during propulsion of the vessel hull at different speeds under different seawater conditions.

Stern flap corrective motion and fuel saving control system for marine vessels

A dualistic stern-appendant device comprises, in integrated form, at least two gate-supportive bodies and at least one flap-hydrodynamic body. The device is characterized by an alternating arrangement of bodies (totaling an odd number of at least three bodies) whereby no two consecutive gate-supportive bodies are next to each other and no two consecutive flap-hydrodynamic bodies are next to each other. Each gate-supportive body has an upper surface which is a gate-supportive surface, all of the gate-support surfaces together representing a cumulative gate-supportive surface. Each flap-hydrodynamic body has a lower surface which is a flap-hydrodynamic surface, all of the flap-hydrodynamic surfaces together representing a cumulative flap-hydrodynamic surface. The geometric plane defined by the cumulative gate-support surface is not encroached upon by any flap-hydrodynamic body. The ship's bottom hull surface and the cumulative flap-hydrodynamic surface together represent an extended, continuous bottom hull surface having associated hydrodynamic benefits (e.g., improved ship's powering).

Hydrodynamic and supportive structure for gated ship stern

The inventive combination of a stern wedge and a stern flap demonstrates hydrodynamic properties which, for purposes of enhancing the powering performance of a ship, are superior to those of either a solitary stern wedge or a solitary stern flap. For many inventive embodiments, the stern wedge portion's lower surface and the stern flap portion's lower surface are slanted at approximately equal angles with respect to the buttock centerline, thereby optimally consolidating the stern portion's lower surface and the flap portion's lower surface so as to effectively create an overall hydrodynamic lower surface which is slanted approximately at one and the same angle.

Combined wedge-flap for improved ship powering

A towing post provides a floating transducer platform on a carriage which arranged for motion in a vertical direction above the center of pressure of a model being tested, for example, by towing across or through a towing basin. Linear bearings are attached to a carriage and engage vertical tracks extending between top and bottom fixed plates of the towing post. One or more transducers may be attached, one above the other, between the floating platform and the model and thus extend through an aperture in the lower plate. Attachment to the model through a gimbal located at the center of pressure of the model allows separation of a measurement, such as of drag, from effects of position and, if desired, a wide range of motion through one or more degrees of freedom, such as pitch and roll. Effects of towing post effects on trim are also eliminated and improved restraint of other motions is achieved. By accommodating more than one force transducer additional measurements can be made for calibration and/or adjustment which, for example, allow effects of yaw to be completely separated from drag measurements.

Floating platform tow post

To reduce the total ship resistance and to improve a propeller efficiency and cavitation performance due to the reduced thrust loading on the propeller for ships or vessels having a sonar dome or an equivalently shaped designs located below the baseline of the hull, a teardrop-shaped bulbous bow is attached to the ship stem bow between the forward perpendicular of the bow and 12.7 ft forward of the forward perpendicular of the vessel, inclusive, and between the ship design waterline and the baseline. The bulbous bow is separate and discrete, and spaced from the sonar dome and has a shaped of a teardrop. The teardrop shaped bulbous bow is mounted to the ship stem bow with the round end portion pointing in the forward direction and the pointed end portion pointing in the aft direction.

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Frederick, MD, United States of America

Dominic S Cusanelli