GB2167352A - Underwater craft - Google Patents

Abstract

An underwater exploration craft consists of a pressure vessel which may contain one or more operators and which has one or more propellors which are adjustable in order to give the craft manoeuvrability. It is analogous to an underwater helicopter. The craft may be used for difficult submarine work at great depths, and is particularly valuable in undersea salvage operations where its manoeuvrability enables lines to be attached to an object to be lifted, e.g, a sunken ship, those lines then being pulled upwards to lift the submerged object. Winches may be provided to pull on the lines, conveniently mounted on a substantial size lifting platform, e.g. an iceberg.

Description

SPECIFICATION Underwater craft This invention relates to underwater craft, particularly craft for exploring at substantial depths.

There is a constant need for underwater craft which are capable of operating at greater and greater depths. Use of such craft are in scientific research, undersea mining, and similar exploratory activity. Any such craft which is to be manned must comprise a rigid pressure vessel, preferably one where the occupants are able to work in conditions of around atmospheric pressure and normal temperature.

Up till now, so called bathyspheres which have been developed for this use have been severely limited in their mobility which places severe limitations on their usefulness.

According to the present invention there is provided an underwater craft consisting of a pressure vessel and at least one propeller attached thereto, the pressure vessel containing a power source and means for converting the power to rotation of propellers, the craft also including control means for adjusting the propeller blades to enable the craft to be manoeuvered under water.

The craft of the present invention is analogous in its operation to a helicopter. Instead of the use of a propeller to hold up a heavierthan-air machine, the propeller is used to hold down a (generally) lighter-than-water craft. The craft of the present invention, at least when operational at depth, is preferably designed to have overall buoyancy, such that should the craft fail for any reason, e.g. there be a loss of power, the propeller(s) would simply stop turning, and buoyancy would return the craft to the safety of the surface automatically.

In order to conserve power which would be needed to hold an overall bouyant craft below the surface, the craft may be initially provided with jettisonable weights, which weights would simply submerge the craft until the required depth had been reached, whereafter they could be jettisoned and the craft could then proceed under its own power for as long as desired or until its power supply has run out. If desired, the craft could be operated as a heavier-than-water machine initially, with the propeller(s) acting to raise a craft which would otherwise sink, weights being jettisoned when it was desired to surface.

The propller or propellers are preferably surrounded by some sort of cage in order to prevent damage, impact with large fish or rocks and the like.

The mode of control of the propeller may be any convenient system enabling the rotational speed, angle of inclination and pitch of the blades to be adjusted. In order to stop counter-rotation of the pressurised vessel in a direction opposite to the rotation of the propeller, a suitable auxiliary propeller may be provided rotating around an axis substantially at right angles to that of the main propeller, or counter-rotation may be stopped e.g. by a water-thrust. Alternatively, two counter-rotating coaxial propellers may be used.

Preferably the propeller(s) is arranged to be above the vessel rather than below it in order to reduce the disturbance caused by the rotation of the propeller(s) on the sea floor, if the craft is being operated on the sea bed. The number and location of the propellers will depend on the particular design, for example, an elongate vessel could have a pair of coaxial or side by side contrarotating propellers set at either end. In such a multi-propeller arrangement control of attitude may be effected by varying the speeds of the propellers individually, rather than varying pitch or inclination.

The interior of the vessel may be provided with appropriate control and life support systems, as well as means for controlling things outside the vessel e.g. the jettisoning of weights, the operation of scoops, grabs or other tools. Such systems are well known already and need not be further described here.

The flexibility of the craft according to the present invention makes it ideally suited to deep water operations involving relatively delicate tasks. In contrast to attempts at deep sea mining and the like which tend to use a sledgehammer approach involving large pieces of plant with little respect for the conditions on the bottom of the sea bed, the craft of the present invention can be used for delicate operations such as underwater archeology. Thus, for example, the craft of the present invention is ideally suited not only for exploration at great depths but e.g. for enabling lifting ropes or the like to be attached (for example by underwater welding) to items which it is desired to lift from the bed of the ocean to the surface.

In order to achieve such lifting operations successfully, it is necessary to be able to attach appropriate lifting wires or the like with proper securement and positioning to the desired object.

In another aspect, the present invention provides methods of lifting articles from the sea bed which comprises attaching, for example, using an underwater craft as described above, a plurality of lifting lines to the article to be lifted, attaching the upper ends of the respective lines to a lifting platform, for example, each to a winch, the points of attachment to the lifting platform corresponding geometrically to their points of attachment on the article, and lifting the item from the sea bed by putting on the lines.

Naturally the platform must be appropriately sized to enable the winches to be set out on the platform in matching array and enable the item in question to be lifted rather than the platform be submerged as the winches are operated. This is fundamentally a question of the size of the platform, i.e. the extra displacement before it submerges, and in some cases, e.g. for lifting substantial weights from the sea bed, or for detaching substantial items from the sea bed, the platform may have to be very large. A suitable large platform would be an iceberg to which winches had been attached. An iceberg has very substantial advantages over any sort of floating winch platform, particularly where it is desired to apply a very substantial upward pull. The cost of constructing a floating platform, particularly one which was capable of taking the varying strains imposed by a number of winches set at different points on it, without breaking up, would be very substantial. The only cost of using an iceberg is the cost of towing the iceberg to the required position, mounting the various lifting winches on it in the desired array, and providing a plurality of vertical bore holes through which the lifting lines are to pass.

Preferably when operating in any such way, the winches are all arranged to be finely controllable in terms of the tension exerted by each winch in the lifting wire, so as to enable the tension to be applied evenly to the object it is desired to lift.

Claims (9)

1. An underwater craft consisting of a pressure vessel and at last one propellor attached thereto, the pressure vessel containing a power source and means for converting the power to rotation of the propellors, the craft also including control means for adjusting the propellor blades to enable the craft to be manoeuvred under water.

2. An underwater craft according to claim 1 and having overall buoyancy.

3. An underwater craft according to claim 1 or 2 and having jettisonable weights attached thereto and including means for jettisoning the weights when required.

4. An underwater craft according to any of claims 1 to 3 wherein the propellor or propellors are surrounded by a protective cage.

5. An underwater craft according to any one of the preceding claims and including one or more sets of counter rotating, coaxial propellors.

6. An underwater craft substantially as hereinbefore described.

7. A method of lifting articles from the seabed which comprises attaching a plurality of lifting lines to the article to be lifted, attaching the upper ends of the respective lines to a lifting platform, the point of attachment to the lifting platform corresponding geometrically to their points of attachment on the article, and lifting the item from the seabed by pulling on the lines.

8. A method according to claim 7 wherein the lifting platform is an iceberg.

9. A method according to claim 7 or 8 wherein the lifting lines are attached to a plurality of computer controlled winches, the computer control being adapted to enable the tension applied by each winch to be applied evenly to the object it is desired to lift.