WO1999037532A1

WO1999037532A1 - Arrangement of a ship's construction

Info

Publication number: WO1999037532A1
Application number: PCT/NO1999/000004
Authority: WO
Inventors: John G. Johnsen
Original assignee: Johnsen John G
Priority date: 1998-01-06
Filing date: 1999-01-06
Publication date: 1999-07-29
Also published as: AU1789799A; NO980054D0

Abstract

A device of a vessel construction is disclosed, especially vessels which are intended for the transfer of cargo in the form of liquids, where the vessel's cargo volume is, by the arrangement of longitudinal partition walls, divided into one or more longitudinal tank sections, and the longitudinal tank sections are by means of transverse partition walls or thwartship bulkheads, divided in a number of mutually adjacent single tanks which may contain the cargo, and where there is arranged for devices (11) for loading and unloading, and means for transferring of liquid from the loading means and to/from the single tanks. The device is characterized in that the transferring means involves that each thwartship bulkhead between the single tanks comprises a water through flow opening (A, A',..D, D', E) the lower edge of which is positioned in a distance above the tank bottom (14) so that the level of the lower edge for a row of the openings for the through flow of water (A, A',..D, D', E) increases gradually from the loading/unloading means or area.

Description

Arrangement of a ship's construction.

The present invention relates to a system for ballasting of vessels. More precisely the invention relates to a device of a vessel construction, especially vessels which are intended for the transfer of cargo in the form of liquids, where the vessels loading volume is, by the arrangement of longitudinal partition walls, divided into one or more longitudinal tank sections, and the longitudinal tank sections are by means of crosswise extending partition walls or thwartship bulkheads, divided in a number of mutually adjacent single tanks which may contain the cargo, and where there is arranged for devices for loading and unloading, and means for transporting of liquids from the loading means and to/from the single tanks .

Moreover, the invention relates to an application of the device. It is an object of the present invention to provide for a new device of a hull construction which provides for an improved means of stabilizing the vessel when under ballast.

It is further an object of the invention to provide for a device where the cargo in the form of liquid itself may be used for the ballasting of the vessel in its unloaded condition. It is further an object of the invention to provide for a device which is especially suitable for the construction of tankers and barges.

It is further an object of the invention to provide for a device which improves the stability of tankers or barges intended for the transport of liquids, oil, seawater, freshwater, and other similar liquids which are suitable for transporting in larger tanks.

According to the present invention there is provided for a device which is characterised in that the transferring means involves that each thwartship bulkhead between the single tanks comprises an opening for water through flow, the lower edge of which is positioned at a distance above the tank bottom so that the lower edge level of a row of water through flow openings increases gradually from the loading/unloading means or area.

The further characterising features of the invention are stated in the following dependent claims 2-6.

According to the invention the device may be used for the ballasting of vessels, i.e. for stability control, where a portion of the liquid cargo is retained after the unloading, and function as ballasting liquid. A vessel of this kind may be used for the transport of liquids, such as oil or water (freshwater) . The device may be included as a construction of a tanker or barges, or older vessels may be reconstructed in order to include the device, or that older ordinary tankers are rebuilt for exclusively barge functions in that all its equipment, for example propulsion engines, auxiliary engines, propellers etc., are dis- assembled and removed.

By a modification as mentioned above, large reconstructed tankers, possibly by rebuilding into the barge form, may be used for the transport of freshwater in amounts of 300-400.000 tons which may be unloaded in a simple and rapid manner by means of the installed loading- pumping equipment. 3

In the following embodiments the invention shall be described, which are only considered as examples, and by reference to the accompanying drawings, wherein:

Fig. 1 shows a lengthwise top plan section of the hull of a vessel wherein the invention is used.

Fig. 2 shows a longitudinal vertical section for the hull of a vessel where the invention is used.

With reference to fig. 1-2 there is shown schematic a hull of a vessel or barge hull F in a plan section and a side section, respectively, the bow being indicated at 16 and the stern at 18. By means of two longitudinally extending vertical partition walls/longitudinal bulkheads 30,40, the hull is divided into three longitudinally extending tank sections 22,32,42, extending mainly between the stern portion 18 of the vessel and its bow portion 16. For the purpose of the stability of the vessel on heavy seas there is no fluid communication between the three lengthwise extending tank sections 22,32,42 through the partition walls/the bulkheads 30,40. In each of the longitudinally extending tank sections 22,32,42 partition walls or thwartship bulkheads are arranged, dividing the longitudinal tank sections in a number of single tanks 1- 10, see fig. 2. A pump 11 for loading and unloading is installed in each of the three central tanks 1 of the vessel, which acts as the pumping well itself. The pump pumps the liquid upwards from the well bottom 1 through the hose or pipe 13. Hoses/pipes, not shown, lead further from the pump 11 to a plant for further processing, either to a liquid source for loading or the area of use, such as ashore, or the like.

In the transverse bulkheads between the single tanks 1-10 there is provision for openings for water through flow, where the lower edge of the opening A in tank 1 exhibits the shortest distance from the tank bottom 14, while the opening of the bulkheads B,C,D,E of tanks

2,3,4,5,6 have their lower edges gradually of increasing levels compared to the opening A. The lower edge levels in each row increase gradually so that they form a completely or partly straight line, so that the tank being positioned furthest from the loading/unloading area 1 exhibits the greatest level of the lower edge above the tank bottom 14. Optionally, the lower edge levels in each row may increase gradually so they establish a curved form, f.eks. having an exponential course, so that the tank being positioned furthest from the loading/unloading area exhibits the greatest level of the lower edge above the tank bottom 14. All the tanks are provided with venting means arranged on deck level, and which may discharge gasses such as air from the tanks during loading, and allow gasses such as air to enter during unloading of the liquid.

These specific features according to the invention imply great significance for the stability of the ship when the tank ship is towed further into the open sea after the unloading has been completed.

Liquid, such as freshwater, is filled by operation of the pump 11, optionally by a free onboard flowing through the pipe 13 to the centre tank 1, and will then gradually flow through the partition wall openings A,B,C, D,E and into the respective tanks 2,3,4,5,6 forward towards the bow 16 of the ship, and through the partition wall openings A' ,B' ,C ,D' ,E' and into the respective tanks 7,8,9,10 backwards towards the stern portion 18 of the vessel. The unloading may take place in the opposite succession. After finishing the unloading the vessel still contains freshwater in each of the tanks 1-10, in that the volume of the freshwater is determined by the threshold level defined by the lower edges of the respective partition wall openings. The tank A has the lowest lower edge level above the tank bottom and the lower edge levels B,C,D,E increase gradually in the tanks 2,3,4,5, while the openings B',C',D' exhibit lower edge levels which compared to A increase gradually in the tanks 7,8,9,10.

Due to the through flow openings of the transverse bulkheads the longitudinal tank sections function in combination as a large open single tank, wherein the remaining ballasting freshwater, will flow from fore and aft towards the pump well or tank in the vessel's central area of gravity, during the vessels upwards and downwards movement during propulsion, such as towing or the like in head sea, having a favourable stability effected during sailing.

If the openings are positioned at the same level level as the first one, adjacent to the pump section, the water will accumulate forward or astern and thereof follows a deterioration of the stability condition.

When the vessel is unloaded and is to leave the harbour, it must, by normal operation of the tanker vessel, take in ballast, normally seawater, in an amount constituting ca . 25% of the cargo capacity, and which has to be discharged by pumping when the vessel again is loading cargo (freshwater) and this involves waste of time and energy consumption up to 50% of the total pump energy consumption. This is completely avoided by the use of the modified vessel according to the invention. The through flow openings of the transverse tank bulkheads will effect that the remaining ballasting freshwater of the tanks will have to flow towards the pump well or tank number 1 during head sea movements of the vessel in open seas, and accumulates in the central part of the vessel or the area of gravity, from which it follows a stabilizing influence. In each of the tanker bulkheads between the single liquid tanks there may be arranged, according to a preferred embodiment, lock gates/flaps which may be manoeuvred so that the openings of the transverse tank bulkheads are adjusted to a through flow section in accordance with the capacity of the unloading pumps. Thus in each of the through flow locks, a lock gate flap which may be elevated and lowered may be mounted for effecting said adjusting of the opening section. The flaps may be anchored on guiding rails mounted to each transverse tank bulkhead on both sides of the opening. The flaps may be moved by means of a driving motor suitable therefore.

Claims

C L A I S .

1. Arrangement of a vessel construction, especially vessels which are intended for the transfer of cargo in the form of liquids, where the vessels loading volume is, by the arrangement of longitudinal partition walls, divided into one or more longitudinal tank sections, and the longitudinal tank sections are by means of crosswise extending partition walls or thwartship bulkheads, divided in a number of mutually adjacent single tanks which may contain the cargo, and where there is arranged for devices for loading and unloading, and means for transporting of liquids from the loading means and to/from the single tanks, characterised in that the transferring means involves that each transverse bulkhead between the single tanks comprises a water through flow opening (A, A' , .. D, D' , E) , the lower edge of which is positioned in a distance above the tank bottom (14) so that the level of the lower edge for a row of the water through flow openings (A, ¹,. . D,D',E) increases gradually from the loading/unloading means or -area.

2. Device in accordance with claim 1, characterised in that the loading/unloading means or the area is arranged in connection with a mainly central tank (1) in the row (1-10) of tanks, and the lower edge level of the two rows of the water through flow openings (A,B,C,D and Z B', CZ D¹, E') extending backwards and forwards respectively from the central tank (1) , increases gradually.

3. Device in accordance with claim 1-2, characterised in that the lower edge levels in each row increase gradually so that they form a completely or partly straight line, so that the tank which is positioned furthest from the area of loading/unloading, exhibits the greatest level of the lower edge above the tank bottom (14) . 7

4. Device in accordance with claim 1, characterised in that the lower edge levels of each row increase gradually so that they establish a curved shape, for example having an exponential shape, so that the tank which is positioned furthest from the loading/unloading area exhibits the greatest lower edge level above the tank bottom (14) .

5. Device in accordance with any of the proceeding claims, characterised in that one or more of the through flow openings comprise regulating means, such as through flow lock gate which may be elevated and lowered, to adjust the liquid through flow in accordance with the prevailing loading/unloading capacity.

6. Device in accordance with any of the proceeding claims, characterised in that the through flow openings of the bulkhead walls defining said central tank (1) of the vessel, is positioned approximately adjacent to the tank bottom (14) .

7. Use of a device according to claims 1-6, for the ballasting of vessels, i.e. for stability control, where the liquid cargo which remains after the unloading, (fungerer) functions as ballasting liquid.

8. Use of a device according to claims 1-6, for the transport of liquids, such as oil or water (freshwater) .

9. Use of a device according to claims 1-6, during the construction of tankers or barges.