GB2308835A

GB2308835A - Buoyant Paddle Screw Propeller

Info

Publication number: GB2308835A
Application number: GB9600136A
Authority: GB
Inventors: John Wilkinson
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-01-04
Filing date: 1996-01-04
Publication date: 1997-07-09
Anticipated expiration: 2016-01-04
Also published as: GB9600136D0; GB2308835B

Abstract

A buoyant paddle screw propellor 1 comprises a plurality of segmentally shaped buoyancy tanks arranged to form a cylinder about a central horizontal transmission shaft 3, with a plurality of angled paddle blades 2 distributed about the outer surface of said cylinder. The transmission shaft 3 is driven by gearing of a marine craft power transmission system. In use the buoyant paddle screw propellors 1 are arranged to work in diametrically opposite pairs mounted fore and aft, or port and starboard on a marine craft structure, to lift the structure clear of water and to produce marine craft displacement and steerage on water (see Fig 6). The marine craft may also be used on land.

Description

BUOYANT PADDLE SCREW PROPELLOR.

This invention relates to a buoyant paddle screw propellor.

Paddlewheel and screw propellors are well known marine craft propellors comprising a paddle mounted wheel or a screw propellor axially mounted adjacent the rearward end of a marine craft structure therefrom transmission means connect a marine engine whereby propellor rotations propel.

Marine craft under way encounter constant water resistance, the advent of air cushioned hovercraft liberated marine craft from water immersion constrictions,engine derived air cushions divert propulsion fuel,buoyanc derived enclosed air cushion propellors which are synchronious with still water may change the way water resistance is overcome.

According to the present invention there is provided a buoyant paddle screw propellor comprising a radially disposed assembly of integral or demountabl e buoyancy chambers which converged centre defines a transmission shatt therein,a set of paddle blades peripherally distributed round the said propellor in frusto-spiral formation,a means of transmission to impart variable and dual rotation to the said propellor by connecting the said transmission shaft to a marine craft power transmission system such as a marine craft mounted gearboxed transmission gear , a components provision such as fasteners, bearings and access hatches, means for mounting the said propellor on to a marine crafts structural parts such as bearings which means may include land related steerage when a marine craft is amphibian.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a pair of buoyant paddle screw propellors; Figure 2 shows a related marine craft main frame; Figure 3 shows elevations of a marine craft with propellors; Figure 4 illustrates a shore based amphibian marine craft; Figure 5 shows diagrams of water lines; Figure 6 shows diagrams of marine craft manouverability; Figure 7 shows mounted and demounted propellors where an amphibian craft has beached for damage repair.

Referring to the drawings,the buoyant paddle screw propellor 1 comprises of segmental shaped buoyancy chambers assembled to torm a cylinder with variably shaped ends and a radially common transmission shaft, the assembly installs with a diametrically opposite assembly member Fig 1 where transmission shafts 3 mount the propellors to a marine craft structure,thereon to marine craft mounted mechanical or electric motors, paddle blades 2 installed in frusto-spiral form provide a screw propellor when the propellors are not rotationally synchronised thereby changing marine craft directions,where propellors 1 converge to a marine crafts central aft and bow plates the propellor 1 cylinders may frustrate to a conical flare 4 for optional transmission gear access and,in particular, marine craft stability.

Propellors 1 submerge to almost half of total volume thereby freeboarding the marine craft structure by buoyancy displacement lift, first blade lift, and deep blade propulsion when propellors 1 rotate in water.

A marine craft Fig 2 mainframe 5 of welded steel off flat pre-formed plate with a stabilizing suspended hold 6 and propellor supporting bow and stern plates 7 is shown ready for assembly as for example a ferry boat or similar.

Elevations of a marine craft Fig 3 mounted with four buoyant paddle screw pro ellors 1 shown disposed on the bow and stern plates 7,a suspended stabiliizing hold 6 amidships may best be seen on the side elevation,the hold 6 clears water when the marine craft is under way ,an inverted plan shows the underside and propellors 1 are endwardly reversed as a air in fore and aft positions on the mainframe 5 for dock manouvering when the coupled propellors 1 contra-rotate thereby screw propelling.

A shore based amphibian marine craft Fig 4 with a hold 6 is illustrated which has limited land steerage by propellor 1 differential rotation traction on aggregate ground,the illustrated amphibian may take different form such as eight propellors 1 and side access drop ramps (not shown)as a military dry beach landing craft.

Diagrams Fig 5 show underwater profiles of a propellor 1 mounted marine cratt stopped and underway.

Diagrams Fig 6 show underwater propellor action which action is indicated by superimposed revolution related vectors found on the propellors,arrows may be seen related to marine craft displacement action diagram 8 shows a12 propellors 1 revolution rate synchronious thereby paddle propelling, diagram 9 shows revolution rate non-synchronious bow pro ellors to change marine craft direction thereby paddle\screw propelling, iagram 10 shows sideway movement of a marine craft where all propellors 1 are revolution rate synchronious in contra-rotatation fore and aft thereby screw propelling abeam, diagram 11 shows a marine craft going about, where all propellors 1 are revolution rate synchronous in contra-rotation port and starboard thereby paddle propelling about axis 12 points bow and stern torquing clockwise, screw propelling also contributes on bow propellors only,stern screw propelling is negative found on the right of diagram 11.

A tubular and splined transmission shaft 3 shown on Fig 7 demounts a propellor 1 from an amphibian marine crafts projecting cantilever support shaft 14,remounting shaft 3 and propellor 1 connects a hub splined wide chord transmission gear within a gearbox 13 where a power driven transmission gear pinion meshes to drive the said wide chord transmission gear,a replacement buoyancy chamber 15 repairs a damaged propellor l,the upperworks of such a notionally derived marine craft,the apron,the wind deck and flying sponson contain propellor 1 spray when such a marine craft leaves a beacon and puts to sea.

Claims

1. A buoyant paddle screw propellor comprising a radially disposed assembly of integral or demountable buoyancy chambers which converged centre defines a transmission shaft therein, a set of paddle blades peripherallv distributed round the said propellor thereon secured in frusto-spiral formation,a means of transmission to impart variable and dual rotation to the said propellor by connecting the said transmission shaft to a marine craft power transmission system such as a marine craft mounted gearboxed transmission gear, a components provision such as fasteners,bearings and access hatches, means for mounting the said propellor on to a marine crafts structural parts such as bearings which means may include land related steerage when a marine craft is amphibian.

2. A buoyant paddle screw propellor substantially as described herein with reference to Figures 1-7 of the accompanying drawings.