US3477401A

US3477401A - Oil tanker

Info

Publication number: US3477401A
Application number: US726827A
Authority: US
Inventors: Akio Hayama
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-05-15
Filing date: 1968-05-06
Publication date: 1969-11-11
Anticipated expiration: 1986-11-11
Also published as: GB1212122A; DE1756370A1

Description

Nov. 11 1969 AKIO HAYAMA 3,477,401

OIL TANKER Filed May 6, 1968 ATTORNEYS United States Patent Int. Cl. B63b 25/12,- B63g 8/00 US. Cl. 114-74 1 Claim ABSTRACT OF THE DISCLOSURE The tanker has a hull, an air tight and water pressure resistant bridge portion on said hull, ballast tanks and a water tight engine space in said hull having a propulsion engine therein. The hull has a pluralityof compartments therein, the lower portion of each compartment being air tight and the upper part having holes therein. A flexible bag is provided in each compartment having the edges thereof secured in air tight engagement with the Walls of the compartment between the upper and lower portions thereof, and an oil inlet and discharge means is provided in the lower portion of each compartment for feeding and withdrawing oil from within the bag in the lower portion of the compartment.

The present invention relates to an oil tanker which is equipped with a sea water compartment having therein an oil tank of variable capacity.

In order to improve the economy of shipping in ships, there is a strong tendency to make ships larger, faster and more specialized. In the structure of a ship, too, various ways have been developed in order to eliminate wave resistance and induced drag (induction effect).

The present invention aims at obtaining the same effect for a submarine in respects of resistance and waves.

The oil tanker constructed in accordance with the present invention has various operational equipment similar to that of a submarine including an air-tight bridge house which has periscopes, snorkel equipment and a residential area in order to maintain sufiicient watch and communication when the main body of the ship goes under water; an engine room; sea-water inducing and discharging equipment for the main ballast tanks which can be remote controlled from the bridge house when the ship submerges or surfaces; an automatic control system in which an underwater navigation helm, a horizontal helm and avertical helm can be operated by electro-hydraulic valves; buoyancy; an automatic control system for trim adjustment.

The invention will now be described in connection with the accompanying drawings in which:

FIG. 1 is an elevation view of the main body of the oil tanker, into the openings of which outside water pressure can be induced;

FIG. 2 is a section at A-A line of FIG. 1 and show ing the situation in which no oil is loaded in the tanker and a pressure-resisting bag is in a position along the ships bottom and the main body of the ship submerges full of sea water in its cargo compartments and the oil tank of variable capacity is unformed;

FIG. 3 is a similar view showing the situation in which oil is present in the cargo compartments, the pressureresisting bag is pushed upward, the oil tank of a variable capacity is filled with oil and the body of the ship is submerged;

FIG. 4 is a partial perspective view partly in section showing how the pressure-resisting bag is fixed onto the walls of the cargo compartments and showing a flexible air exhaust tube passing through the pressure-resisting bag.

3,477,401 Patented Nov. 11, 1969 The amount of pressure has no relation to the direction in which it works. Similarly, water pressure is a force which works upon a unit area and its c.g.s. unit is g./cm./sec. dyne/cmF. In oceanography, 10 dyne/ cm. 1 dembal (db) is used as a unit. Water pressure in creases in accordance with the increase in depth. When setting a Z shaft as being right downward, water pressure at a certain depth is expressed as follows.

11 P=f Dgdz In this formula, P is density and g is acceleration of gravity. As this formula shows, water pressure increases by about 1 atmospheric pressure when the depth of water increases by 10 m. Thus, in order to construct a ship similar to a submarine, it is required to provide an airtight hull structure which is strong enough to withstand water pressure.

In the present invention, the bridge house containing a residential area and the engine room are made air-tight and the hull containing the cargo compartments has many small holes in the upper portion thereof covered by screens so that sea-water can flow into the partitioned compartments. The lower portion of each compartment is airtight. A flexible, water-proof and pressure-resisting bag, which is made of a textile sheet of strong fibre such as neoprene reinforced nylon or a rubber sheet, is prepared in a shape suitable for each of these partitioned compartments and as shown in FIG. 4 the cylindrical head on each edge of the bag is fixed onto the walls of each compartment by a molding 3 positioned between the upper and lower portions of the compartments. An air-exhaust tube 4 which is connected with a vacuum pump is passed through the bag at an appropriate place. Thus, an oil tank of variable capacity is formed between the ships bottom and the bag 1. An oil pipe 13 for loading and unloading or oil is provided at the ships bottom and is to be connected with an oil pump.

In the present invention, in order to keep the gravity of the floating body in the lower part of the main body 9 of the ship when it is unloaded, sea water is placed into some part of the compartment for trim adjustment. By this means together with the use of the main ballast tanks, it is possible to stabilize the ship when it is afloat.

When the ship leaves port unloaded for the purpose of loading oil, the bag 1 of each oil tank 14 of variable capacity from which the air has been exhausted by the vacuum pump takes a position in which it covers the bottom of the tank as shown in FIG. 2, and sea water 15 coming through a water inlet 5 fills each compartment 2. Due to this and also due to the balancing effect of the main ballast tanks 17, the main body 9 of the ship submerges below water level WL and at a depth of 5 m. to 10 m. leaving a part of the air-tight bridge house 7 exposed above the water surface. Thus, the ship navigates under water to a port of destination watching its route by a periscope 6.

Air supply and exhaust for the bridge house 7 and the engine room is done by snorkel equipment 10. A main engine 11 can be operated either by hand or by remote control. Sea water 15 is allowed to flow into the compartments 2, so that all the other parts of the main body of the ship excepting the air-tight structure are free from the influence of water pressure and the ship is quite safe in spite of the increase of about 1 atmospheric pressure at a depth of about 10 in.

When the ship arrives at a port of destination and starts loading of oil, the oil stored in a tank either on the ground or on the sea is supplied to the ship through the oil pipe 13 which is fixed on the ships bottom. Then, the bag 1 is pushed upward with the inflow of oil and the capacity of the oil tank keeps expanding; while, the sea water 15 in the compartment 2 is gradually discharged because the supplying pressure of the oil pump is over 1 atmospheric pressure. When the tank capacity has reached to the maximum, there remains almost no sea Water in the compartment 2. In the oil tank 14 of variable capacity formed by the pressure-resisting bag, it may happen sometimes that air-pockets are produced when oil is supplied by the air pump and that they get together to form a mass of air. But, they can be taken out by appropriate operation of the vacuum pump. This contributes to the supplement of water pressure resisting strength and to trim adjustment.

When loading ends, the ship leaves for the home port navigating under water at a constant depth of 5 m. to m. i.e. the depth at which the main body of the ship receives little influence of waves, resistance and water pressure.

During navigation or at the time of temporary anchoring, it is easy for the ship to operate similar to a submarine such as surfacing the main body by blowing the main ballast tank appropriately.

Generally, from a structural point of view, an oil tanker has a disadvantage that explosion or fire occurs easily. That is to say, even when a ship is unloaded, there may remain some amount of oil in the compartments, due to which evaporated gas is easily generated and stays in the compartment. When the ship is fully loaded, the contact between the surface of oil and the air causes the evaporated gas to stay there. Especially, when the ship navigates in an area of high temperature, generation of evaporated gas is great due to the abovementioned reason and also due to the rolling motion of the ships body.

In the present invention, however, no evaporated gas is generated in the compartments as oil is not loaded directly into the compartments. Further, whether oil is loaded in the oil tank of variable capacity or not, no air is present in the tank and consequently evaporated gas is not generated and there is little danger of explosion or fire.

As described above, the oil tanker constructed in accordance with the present invention has the advantage that it can navigate under water without much resistance at a high speed with small horsepower and thereby it has great mobility and a high rate of operation. Another advantage is that it does not need a completely airtight hull structure which is normally indispensable for a submarine and therefore the cost of construction is reduced substantially.

It is of course possible to carry out changes in design provided such a change does not deviate from the purpose of the present invention.

What I claim as my invention is:

1. An oil tanker, comprising a hull, an air tight and water pressure resistant bridge portion on said hull, ballast tanks and a water tight engine space in said hull having a propulsion engine therein, and said hull having a plurality of compartments therein, the lower portion of each compartment being air tight and the upper part having holes therein, a flexible bag in each compartment having the edges thereof secured in air tight engagement with the walls of the compartment between the upper and lower portions thereof, and oil inlet and discharge means in the lower portion of each compartment for feeding and withdrawing oil from within the bag in the lower portion of the compartment.

References Cited UNITED STATES PATENTS TRYGVE M. BLIX, Primary Examiner US. Cl. X.R.