GB2215677A - Removing water from the hold of a sea-going vessel - Google Patents

Abstract

Apparatus for removing water from the hold of a sea-going vessel, comprises one or a series of upstanding ducts 10 or passageways positioned along one or more sides of the hold of the vessel each including spaced apertures 14 formed with an entry structure shaped to preclude or inhibit the flow of other than liquid therethrough e.g. by louvred entry structures 15. Preferably, the ducts or passageways extend over the full height of the available cargo space within the hold; the lower ends of the ducts or passageways may open onto the floor of the hold or lead directly to bilges positioned below the floor of the hold. The cross-sectional shape of the ducts or passageways is not critical and may be arranged for convenience of installation and inspection; the cross-sectional area of the ducts or passageways should, however, be sufficient to ensure unimpeded flow of water to the bilges in the most extreme conditions. <IMAGE>

Description

Apparatus for removing water from the hold of a Sea-going Vessel This invention relates to apparatus for removing water from the cargo hold of a sea-going vessel; more especially, the invention concerns the removal of water present on the surface of bulk materials present in a ship's hold.

The invention has application both to vessels designed specially for the conveyance of loose solid materials in bulk, and to general cargo ships equipped with 'tweendecks' which may occasionally carry such materials. Typical bulk materials include sugar, sand, grain, iron ore, bauxite, cement, flour, coal and coke.

Although care is taken when loading a cargo prior to sailing to ensure that the centre of gravity of the contents of the or each hold does not rise to a height which would endanger the stability of the vessel when at sea, it is possible that water may enter the hold through the hatches or ventilators either through leakage or as the result of damage caused by inclement weather.

It has been found that some granular materials which are commonly transported in bulk by sea, such as sugar, can in time, form a horizontal barrier to impede the downward flow of water under gravity. Should this occur to such an extent that the influx of water exceeds the rate of downward flow, an increasing volume of unrestrained liquid will accumulate in the upper cargo space on the surface of the bulk material. When the ship rolls, the centre of gravity of this liquid moves so as to affect adversely the return to an even keel, and in extreme cases may cause a capsize.

The risk of this eventuality is increased in vessels which have fewer and larger hatches as the free surface in any one hold affects a greater percentage of the whole ship.

According to the present invention there is provided apparatus for removing water from a hold of a sea-going vessel, the apparatus comprising one or a series of upstanding ducts or passageways adapted to be positioned along one or more walls of the hold of the vessel, the or each duct or passageway including a plurality of spaced apertures each having an entry structure shaped to permit the flow of liquid there through but to preclude or inhibit the flow of solid materials The ducts may be positioned along one or more laterally or longitudinally extending sides of a hold of a vessel.

The apertures may be located in a front face and/or one or both side faces of the ducts or passageways.

Preferably, the ducts or passageways extend over the full height of the available cargo space within the hold; the lower ends of the ducts or passageways may open onto the floor of the hold or lead directly to bilges positioned below the floor of the hold. The crosssectional shape of the ducts or passageways is not critical and may be arranged for convenience of installation and inspection; the cross-sectional area of the ducts or passageways should, however, be sufficient to ensure unimpeded flow of water to the bilges in the most extreme conditions.

The apparatus may take the form of a prefabricated assembly of a back plate, side plates and a front plate which together define the walls of the respective duct or passageway, the spaced apertures being located within the front plate and/or one or both of the side plates.

Alternatively, the apparatus may take the form of a front plate and two side plates, the rear face of the respective duct or passageway being defined by an adjoining surface of the vessel in which it is or is intended to be installed. In this arrangement, the apertures are again located within the front plate and/or one or both of the side plates.

The invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which: Figures 1 and 2 are lateral cross-sections of a conventional sea-going vessel not in accordance with the present invention, illustrating respectively one hold of the vessel when the vessel is lying generally flat in the surface of the sea and when the ship is listing; Figure 3 is a lateral cross-section similar to that of Figures 1 and 2 of a sea-going vessel including apparatus in accordance with the invention; Figure 4 is a partial longitudinal cross-section of a sea-going vessel including alternative or additional apparatus in accordance with the invention; Figure 5 shows to an increased scale a section taken through apparatus in accordance with the present invention Figure 6 shows in perspective view, the apparatus illustrated in Figure 5;; Figure 7 shows in perspective view alternative apparatus in accordance with the invention; and Figure 8 shows in perspective view alternative prefabricated apparatus in accordance with the invention.

The typical sea-going vessel illustrated in Figures 1 and 2 of the drawings comprises a hold 1 containing a bulk granular cargo 2 of, for example, sugar above bilges 3 sited in the double bottom of the vessel. Pumps 4 are positioned in the bilges, below the floor of the hold.

The hold 1 is closed from above by hatch covers 5. When heavy seas break over the ship (the wind blowing in the direction of arrow A in Figures 1 and 2), water leaks into the hold 1 via the hatch covers 5 and accumulates on top of the cargo in the areas indicated by reference numerals 6 and 7.

As will be seen from Figure 2 when, due to the force of the wind, the ship rolls to leeward, the unrestrained water flows from area 7 to increase the volume of water in area 6. The weight of this water acting through its centre of gravity (indicated by reference numeral 8) creates a turning moment about the centreline of the vessel. The vessel will then retain the permanent list as shown if the water cannot be re-distributed equally between areas 6 and 7 or be discharged into the sea. If water continues to enter the hold,, the vessel may capsize.

This is the problem to be met, or at least alleviated by the present invention.

The vessel illustrated in Figure 3 (in which similar integers have been identified by the same reference numerals used in Figures 1 and 2) includes a series of substantially vertically aligned ducts 10 positioned along the two longitudinally extending side walls of the ship's hold 1. These ducts 10 are spaced apart, the actual spacing and the number of ducts provided being dependent upon the size of hold, the type of cargo to be carried and the likely extent of excess water to be removed.

As will be seen from Figure 4 of the drawings (in which similar integers have been identified by the same reference numerals used in Figures 1 to 3), the ducts 10 may alternatively or additionally be positioned along one or more of the lateral partitions or bulkheads 11 which divide the vessel into separate longitudinally spaced compartments or holds 12. Two such holds 12 are shown in Figure 4. It will, of course, be appreciated that more than two holds may be provided. It will also be appreciated that the vessel may comprise both laterally and longitudinally spaced holds; in this case, ducts may be positioned along one or more lateral and/or longitudinal walls of these holds.

As will be seen more clearly from Figure 5 of the drawings, each duct is formed with a series of generally vertically spaced apertures 14. Each aperture 14 is partially shielded by a louvred entry structure 15 whose lower edge 17 depends to a level below that of the lower boundary 18 of the respective aperture 14 and by an outlet structure 19 whose lower edge 20 is sited at a level above that of the boundary 18. Thus, the entry structure 15, is designed to permit the through flow of liquid whilst preventing or significantly inhibiting the through flow of solid cargo materials; and the outlet structure 19 is designed to ensure that liquid discharged through one aperture does not inhibit the discharge of liquid from an aperture below that one aperture.

The ducts 10 communicate directly with the bilges 3 or with the floor of the hold, excess water being removed from the vessel by the pumps 4.

The shape and construction of the ducts 10 and the entry and outlet structures 15, 19 can take many forms, the criteria being that water accumulating within the hold can be removed from or at any level below the surface of the cargo without bulk solid material being similarly removed. Thus, in use of the apparatus illustrated, water collecting in areas 6, 7 flows into the ducts 10 for removal from the vessel in the normal way.

In Figure 5, the entry and outlet structures 15, 19 are shown to be curvilinear. However, these structures could also be linear with the lower edge 17 extending downwardly to a point substantially coincident with that illustrated.

One particular design of duct is illustrated in Figure 6. As shown, the duct comprises a series of plates 21 carried either permanently or removably on flanges 22 of two vertical ribs 23 of the vessel shell 24.

The plates 21 seat above another and include cut-outs to define the apertures 14. The entry and exit structures 15, 19 are preferably formed in one piece and are welded or otherwise secured to the respective plate 21.

Assembly of the plates 21 on the ribs 23 therefore defines the front face of one duct 10 the ribs 23 defining the side faces of the duct and the vessel shell 24 defining the rear face. Assembly maybe achieved by bolts or clips or by providing on the sides of the plates 21 one or more lugs or slots which co-operate with complementary slots or lugs formed in or carried by the flanges 22 of the ribs. It will be appreciated that any conventional method of fixing may be employed. It will also be appreciated that the ribs 23 may be sited to receive the plates at appropriate locations about the hold walls.

In an alternative unillustrated arrangement, the ducts 10 are formed integrally and are positioned permanently along the side walls of a hold. Thus, the several plates 21 may be replaced by a single sheet or plate. The ducts, plates etc. may be manufactured from any suitable material, e.g. cast iron, steel, wood or rigid plastic such as nylon.

In the alternative construction illustrated in Figure 7, linear louvered entry structures 15 are positioned within the vertical ribs 23 which define the two side faces of the duct and the plates 21 are secured to the sides of the ribs 23 to define the front face of the duct 10. The plates 21 extend laterally beyond the ribs 23 to protect the louvered entry structures 15 during loading and unloading of the respective hold. The plates 21 fit closely one above another to prevent the entry of solid cargo materials into the duct 10, and are held in position by bolts, clips, or other means which will permit their removal for internal inspection of the duct when the hold is empty.

In the arrangement illustrated in Figure 8, the apparatus is constructed as prefabricated units each comprising a front plate 25, two side plates 26 in which are formed apertures 27 and a back plate 28 for attachment to an appropriate wall of a vessel hold. Linear entry louvres 15 extend at an angle downwardly over the apertures to facilitate the flow of water and to inhibit the flow of solid materials therethrough.

The prefabricated units may simply be secured to the vessel wall by means of catches 29 which can be turned selectively to hold or release the prefabricated unit in place adjacent the vessel wall.

It is to be understood that the foregoing is merely exemplary of one embodiment of apparatus in accordance with the invention and that modifications can readily be made thereto without departing from the true scope of the invention.

Claims (11)

CLAIMS:

1. Apparatus for removing water from a hold of a seagoing vessel, the apparatus comprising one or a series of upstanding ducts or passageways adapted to be positioned along one or more walls of the hold of the vessel, the or each duct or passageway including a plurality of spaced apertures each having an entry structure shaped to permit the through-flow of liquid but to preclude or inhibit the through-flow of solid materials.

2. Apparatus as claimed in Claim 1 wherein each entry structure comprises a louvre which extends downwardly from the upper extent of the respective aperture and inclines outwardly from the outer face of the duct or passageway to define an entry channel which places the aperture in communication with the hold interior, the lower lip of the louvre extending to a level below that of the lower boundary of the aperture.

3. Apparatus as claimed in Claim 1 or Claim 2 wherein each aperture is formed with an outlet structure comprising a louvre which extends downwardly from the upper extent of the respective aperture and inclines outwardly from the inner face of the duct or passageway to define an outlet channel, the lower lip of the outlet louvre extending to a level above that of the lower boundary of the aperture.

4. Apparatus as claimed in any one of Claims 1 to 3 wherein the duct or passageway comprises an assembly of a plurality of plates carried by ribs which protrude inwardly into the hold from the vessel wall, the plates being seated edgewise one above another and each being formed with at least one said aperture and each carrying at least one said entry structure.

5. Apparatus as claimed in any one of Claims 1 to 3 wherein the duct or passageway comprises an assembly of a plurality of plates carried by ribs which protrude inwardly into the hold from a vessel wall, the ribs each being formed with at least one such aperture and each carrying at least one said entry structure.

6. Apparatus as claimed in Claim 4 or Claim 5 wherein the plates are readily disassembled one from another.

7. Apparatus for receiving water from a hold of a seagoing vessel, the apparatus comprising a plurality of rigid plates each formed with an aperture for the throughflow of water and each partially shielded by a louvred entry structure which extends downwardly and outwardly from the upper margin of the aperture to an extent to preclude or inhibit the flow of other than liquid therethrough, the rigid plates being shaped for edgewise stacking to define the front face of a duct to be positioned adjacent one side wall of the hold of the vessel.

8. Apparatus for receiving water from a hold of a seagoing vessel, the apparatus comprising a plurality of generally vertically aligned rigid ribs which protrude inwardly into the hold from a vessel wall, each such rib being formed within aperture for the through-flow of water and each partially shielded by a louvered entry structure which extends downwardly and outwardly from the upper margin of the aperture to an extent to preclude or inhibit the flow of other than liquid therethrough.

9. Apparatus for receiving water from a hold of a seagoing vessel, the apparatus comprising a prefabricated assembly of a back plate, two side plates and a front plate which together define an open-ended passageway, one or more apertures being formed in the or each side plate and/or the front plate, each such aperture being partially shielded by an entry structure which extends downwardly and outwardly from the upper margin of the aperture to an extent to preclude or inhibit the flow of other than liquid therethrough

10. Apparatus as claimed in any one of the preceding claims wherein the ducts discharge directly into the bilges of the vessel.

11. Apparatus for removing water from the hold of a seagoing vessel substantially as herein described with reference to Figures 3 to 7 of the accompanying drawings.