GB2429685A

GB2429685A - Retractable vessel propulsion unit

Info

Publication number: GB2429685A
Application number: GB0518054A
Authority: GB
Inventors: John Tanat Williams
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-09-06
Filing date: 2005-09-06
Publication date: 2007-03-07
Anticipated expiration: 2025-09-06
Also published as: GB0518054D0; GB2429685B

Abstract

A retractable vessel propulsion unit comprises a mounting plate 4 rotatably mounted to the vessel's hull H by means of a pivot point 3. The mounting plate supports the vessels propeller 9 and propeller support 8 and may also carry the drive means 6 for the propeller. The mounting plate is rotatable about the pivot point between a first position, where the propeller is positioned outside of the hull of the vessel (Figure 2) and a second position where the propeller is retracted within the confines of said hull. The pivot point may also carry a second plate 5 adapted to cover the required opening in the hull when the propeller is in its retracted position. A casing 2 may be fitted over the opening inside the hull to encase the propulsion unit and maintain the integrity of the hull. An inspection window 11 may be provided in the casing to allow access to the propulsion unit.

Description

APPLICATION OF INTERNAL POWER FOR YACHT

MOVEMENT 2 This invention relates to a retractable propulsion unit in a boat.

Background:

Most sailing yachts have a motor to assist movement through the water on windless days and for manoeuvring for example in tight anchorages.

It necessarily follows that the power of the motor has to be transmitted via a power train to a method of propulsion. The commonest method of propulsion is to a propeller or impeller permanently immersed in the water. For the remainder of the description this propeller or impeller or propulsion unit will be called a prop. The prop and its supporting leg because of its permanent position in the water flow over the hull causes a resistance or drag when sailing, and numerous ingenious methods have been devised to reduce this drag.

The ultimate way to reduce the drag of the prop is to remove it from the water flowing over the hull while sailing and the motor not in use.

Essential technical features: The following invention describes a way of removing this prop and its support from the water flow.

This is achieved by mounting the prop and its support on a plate, which is retracted into the hull when not in use the defect in the hull covered by a second plate, part of the rotated unit. This leaves the hull relatively smooth and free of any cause of resistance or drag.

When required the unit is rotated and the prop lowered into the water flow, clear of the hull.

A specific embodiment of the invention will now be described by way of an example with reference to the accompanying drawings in which: Fig I shows the unit in its retracted position with the base plate (5) flush with the hull (H).

Fig 2 shows the unit extended with the base plate vertical and the prop in the water stream and the mounting plate (4) now flush with the hull (H) .

Inside the hull over an appropriately prepared opening in the hull (H) is fixed a casing (2: Fig I & 2). Within this casing is a hinge (3: Fig l&2), running parallel with the long axis of the boat. On this hinge is mounted a base plate (5:Fig I &2), which is flush with the hull when the unit is in a closed position. A mounting plate (4:Fig I&2) is fixed at an angle to this base plate, usually at a right angle. The base plate and the mounting plate rotate as a unit.

The mounting plate has fixed to it a drive unit consisting of a support (8:Fig 1&2), on to which is mounted a prop (9:Figl&2). This unit is similar, for illustrative purposes, to the lower end of an outboard motor or outdrive. The drive shaft passes through the mounting plate to a motor.

(6:Figl &2).

This motor and support unit are firmly fixed to the mounting plate.

The upper part of the casing inside the hull may have an opening (11: Fig 1 &2) on to which is removably fixed a plate which may be transparent.

This will allow inspection of the unit while afloat, and if the boat is allowed to dry out at low tide so that the casing is above the water level, access to the unit to service or inspect it.

When sailing the unit is retracted to the position shown in Fig 1.

When the units are to be used to propel the boat, they are rotated around the hinge (3:Fig I&2) to the position shown in Fig 2. The base plate sits in the water in line with the long axis of the boat and causes minimal resistance.

The units are rotated around the hinge (3), by either; A) An actuator on the outside of the casing acting on the hinge pivot, which in this example, would pass out of the casing through a waterproof seal in the side of the casing. The advantage of this arrangement would be due to its position outside the casing and inside the hull the ease of maintenance of the actuator. Or

B) By placing the actuator inside the casing, acting directly on the mounting plate or on extension of the mounting plate. The advantage of this configuration would be to maintain the integrity of the casing, but with the disadvantage the relative inaccessibility of the actuator other than through the inspection window.

Different sized cases (2 Fig I &2) and different sized openings in the hull would accommodate different sized propellers. Propellers that fold as are currently used in sailing yachts would reduce the size of casing and hull opening.

Motors (6) appropriate to the size of the vessel, the number of units used and the power output of the engine would be selected. The suitable motor units to drive the props would be either electric or hydraulic motors.

By eliminating the need for the engine to be close to andlor in line with the shaft and prop, the engine could be positioned in the best possible position in the hull. A small auxiliary engine such as one usually reserved for electricity generation could also be used in the case of an engine failure.

Using this system two propulsion units which could easily be run off the one engine, this would give the flexibility and manoeuvrability of a twin engine power vessel to any sailing boat.

Claims

1 A mechanism comprising a method of removing from the water flowing over the hull of a moving boat the propulsion unit consisting of a support and an impeller or propeller by mounting them on a plate which can be rotated around a supporting turning point and by the rotation of the plate around the turning point remove them from the water flow and reduce resistance.

2 A mechanism as described in Claim I wherein a casing is fitted over a prepared opening in the hull of a boat to encase the mechanism and maintain the integrity of the hull.

3 A mechanism as described in Claim I and 2 wherein a turning point is mounted in the long axis of the boat inside the casing to support the mechanism.

4 A mechanism as described in Claim 1 and 3 wherein plates are mounted on the turning point and are capable of rotating on the turning point inside the casing and protruding outside the hull A mechanism as described in Claim 1, 3 and 4 wherein a method of propulsion consisting of a motor and propeller or impeller is attached to a plate.

6 A mechanism as described in Claim 1 wherein the plates attached to the turning point inside the casing are rotated around the pivot of the turning point by an actuator.

7 A mechanism as described in Claim I wherein in the retracted position one of the plates maintains the contour of the hull.

8 A mechanism as described in Claim I wherein an inspection window may be inserted in the casing to allow access.

9 A mechanism substantially as described herein with reference to Figures 1 and 2 of the accompanying drawing. L4-