Boat hull with a pivotally mounted hydrodynamic appendage

Abstract

A boat hull with port and starboard side walls that are vertical in cross section while the bottom of the hull immediately prior to the commencement of the stern part there-after is horizontal in cross section. Extending throughout the buoyant hulls stem part a longitudinally rectangular flat plate with port and starboard upwardly extending side walls, one each side, are located throughout the length of the vessels stem part. An upwardly directed second rectangular flat plate is arranged fore/aft extends midway between the afore side walls to a height in excess of the side walls. This upstanding plate butts its lowermost edge onto the mid-line of the first plate. Linking the forward edge of the longitudinally rectangular plate to the buoyant hull at its aftmost and deepest point are hinges.

Claims

1. A boat hull comprising a bottom having a flat mid-section and a angled stern section that reduces in draft towards the stern of the boat, wherein a hydrodynamic appendage comprising a first flat rectangular plate is hingedly attached to the hull at the transition between the mid-section and the stern sections and extends towards the stern, the appendage has side walls extending upwardly from the first plate and an upwardly directed second rectangular flat plate arranged along a fore/aft axis of the first plate midway between the side walls to a height in excess of the said side walls, the second plate locating within an open slot casing that extends within the boat hull, wherein means are provided to raise and tower the hydrodynamic appendage, to pivotally move the first plate towards and away from the stern section.

2. A boat hull as claimed in claim 1 in which the stern part of the hull to comprise two or more similar sections as defined in claim 1 arranged parallel to the fore/aft axis and in line athwartships.

3. A boat hull as claimed in claim 1 or claim 2 where-in the said side walls of the appendage to be of a height to maintain the exclusion of water from outward of the hull.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows an isometric view of all pivotally moveable hydrodynamic appendage removed from the vessel, the upstanding combination plate with port and starboard side walls, extending hinges to thereby link the forward edge of the combination plate to the lowermost trailing edge of the buoyant hull.

(2) FIG. 2 shows an isometric view of the invention attached to the central hull of a multi hull vessel.

(3) FIG. 3 A vessel to comprise at least one hull that in its stern part is longitudinally divided into sections parallel with the fore/aft axis of vessel.

(4) This is a frontal view

(5) FIG. 4 is a side view

(6) FIG. 5 is a plan view

(7) FIG. 6 shows a side view of a single hull vessel according to the invention that has a ballast keel located on the fore/aft central line of the hull and shows a side view of the vessel with ballast keel

(8) FIG. 7 shows a plan view of the vessel

(9) FIG. 8 shows a sailing vessel in which the stern part is divided into three separate sections, each operating independently of other sections and has lee boards port and starboard one each side to resist leeway, shows the vessel in side view

(10) FIG. 9 shows the vessel in plan view

DESCRIPTION OF PREFERRED EMBODIMENT

(11) At the forward-most part of the stern of a buoyant hull, according to the invention, a rectangular plate 5 has its long axis arranged parallel with the fore/aft axis of buoyant hull and with its forward edge coincident with the forward most commencement of the said and that its aftmost edge is generally in the same athwartship plane as the aftmost waterline of the buoyant hull, such that when viewed athwartship the deepest part of the buoyant hull and the afore said rectangular plate 5 occupy the same depth below the water surface and that the upper surface of the said plate 5 is intimately attached to the upwardly extending fin 4 arranged along the first plate's fore/aft midline on its upper surface, such that the aftmost edge of combination plate with port and starboard longitudinal upstanding side walls 2 running the length of each said plate to then terminate aftwardly in the same athwartship plane as the afore-said base plate whilst the fin 4 is inclined forwardly downward to meet the fore/aft midline of the base plate 5 to which it joins, whilst the forward-most edge of the said combination plate are hinges 9 that extend forward to which both the said combination plate and hull are security attached, thereby allowing the said combination plate to hinge between horizontal and the artwardly upward surface of the buoyant hull, the up/down movement of the fin plate 4 occurs within a robust drop-board type housing 6 that is watertight to the buoyant hull and does not require additional attachment of the fin to the buoyant hull, the afore said hinge movement being controlled by suitable means, the simplicity of the afore described system reduces maintenance and has an established record of reliability. 1 Chine 2 Side walls 3 Transom of buoyant hull 4 The upstanding second flat rectangular plate that is a part of the combination plate 5 The first flat rectangular plate of the combination plate is a part of the whole combination plate 6 Upright slot, arranged parallel to for/aft axis of the hull, open aftwardly and at top and bottom 7 Recess in buoyant hull for combination plateor a part thereof 8 Forward athwardship edge of combination plate 9 Hinges 10 Ballast keel 11 Deep central section of the hull 12 Slot and casing for upstanding second plate