US3318278A - Ballasting of ships - Google Patents

Description

y 1967 E. E. HUEBOTTER BALLASTING OF SHIPS Filed Oct. 17. 1966 2 5 f l M M m: M T r H 2 N7 M 1 z 57 7 AL V L w w m f y F. u J w w p W a 1 m f M M 7 1 3 H. v (Z a H mm L n a m MM WRAP m H .A v M q W a V.iA/ KM... .v W m w vwn W 4. U 4i T2 NAN I 7. m t ,6 XV M M flqlLl lh y o m w a\ w J W w m M M @KHI United States Patent Ofifice 3,313,278 Patented May 9, 1967 3,318,278 BALLASTENG F SHIPS Earl E. Huebotter, Houston, Tex., assignor to National Lead Company, New York, N.Y., a corporation of New Jersey Filed Oct. 17, 1966, Ser. No. 587,031 Claims. (Cl. 114-125) This application is a continuation-in-part of my c0- pending application Ser. No. 431,624, filed Feb. 10, 1965, now abandoned.

This invention relates to the ballasting of ships, especially cargo ships, and includes the use of certain heavy liquid compositions therein.

In recent years, the trend has set in of shipping cargo in containers, either use containers or containers designed to facilitate loading, unloading, and subsequent handling ofthe cargo, all in line with the increasing mechanization of transportation. Furthermore, the number of automobiles being moved by ships continues to increase.

Both automobiles and containerized freight are classified as low-density cargo. As a result, when a vessel is filled below the deck with this cargo, only a part of the weight-carrying capacity of the vessel is utilized. Therefore, it becomes desirable to stack cargo, such as containers, above deck until the weight-carrying capacity of the vessel in question is reached. However, stacking containers and other cargo above deck raises the center of gravity of the loaded vessel and reduces its stability.

The stability of a vessel requires that a righting moment be developed between the center of gravity and the center of buoyancy when it is listed. The magnitude of this moment at various degrees of list of the vessel determines its stability. It has, therefore, become necessary to ballast vessels carrying containers, automobiles, or a combination of containers and automobiles, so that their stability is retained while being loaded with high deck loads to attain their maximum weight-carrying capacities.

Vessels are normally ballasted with either a combination of liquid and solid ballast or liquid ballast alone. It is relatively common to provide cargo-carrying ships and barges with a double bottom, the space between the false bottom and the actual bottom of the ship being arranged to carry the. liquid ballast. In some cases, this is water, or depending upon the trade engaged in bythe ship, it may be a payload such as molasses or fuel oil. When solid ballast is used, it is placed on top of the double bottom ballast tanks.

Now in the increasingly frequent cases when a vessel is loaded with low density cargo of the type described, proper ballasting presents 'a number of problems. To the extent that solid ballast may be used, because of its placement as described, it occupies the most valuable cargo space in the vessel. Moreover, the commonly used dense concrete slabs in particular are diflicult to remove in the event that repair must be done to the double bottom ballast tanks or associated areas of the ship. The fluid ballast, which as described is placed in the ballast tanks, does not ordinarily have suflicient density to lower the center of gravity to the desired degree.

It is an object of the present invention to provide a method for altering the center of gravity of vessels having ballast tanks by emplacing therein a high density fluid having proper rheological properties, stability, and suitable high density; and to provide such a fluid.

Other objects of the invention will appear as the description thereof proceeds.

In the drawings:

FIGURE 1 is a cross-sectional view taken amidships of a typical cargo-carrying vessel, showing the double 'bottom ballast tank and the usual placement of lowdensity cargo.

FIGURE 2 is a fragmentary perspective view partially cut away, showing details of the typical double bottom fluid ballast space of the ships of FIGURE 1.

Generally speaking and in accordance with illustrative embodiments of my invention, I provide a water-based, high density fluid in the form of a liquid composition which consists essentially of water, ground barite, a gel-, ling agent, and a deflocculating agent. The ground barite is present in the composition in a quantity sufiicient to impart a density of from about to about pounds per cubic foot. The gelling agent, which is preferably a colloidal clay and more particularly bentonite, is present in a quantity sufiicient to inhibit the settling of the barite. The deflocculating agent is present in a quantity suflicient to prevent excessive gelation of the gelling agent, e.g., bentonite, upon long standing of the composition.

The ground barite is a well-known article of commerce and should be ground to pass a 325-mesh screen and in common with barite of good commercial grade should have a density of about 4.2 0 to about 4.35-the average density of good ground barite averages 4.3.

The gelling agent, such as bentonite, as exemplified by Wyoming bentonite, may be ground to pass a ZOO-mesh screen, although the actual mesh of the gelling agent is unimportant due to the fact that it disperses the water in forming the inventive compositions.

The deflocculating agent is chosen from the class consisting of water-soluble humates, such as sodium humate; water-soluble lignosulfonate, such as sodium lignosulfonate; ferrochrome lignosulfonate; and the like; watersoluble polyphosphates, such as sodium tetraphosphate, sodium hexametaphosphate, and the like; and soluble aminomethylphosphonate salts, as disclosed in British Patent No. 1,032,888, and the parent United States application Ser. No. 230,005, filed Oct. 11, 1962, now abandoned, referenced therein. These may be used singly or in admixture.

These ingredients are admixed as described more fully hereinbelow to give a pumpable fluid having'a density within the range given, and the fluid compositions so prepared exhibit no settling of solids or'sludge, or separation of free-water, even after repeated rocking and vibration over long periods of time. Moreover, they remain in a pumpable condition, so that should repair work become necessary on the ship, the fluids may be pumped out with a minimum amount of difliculty.

Generally speaking, my invention may be carried out in a broad aspect thereof by simply filling into the-ballast tanks of the ship to be treated, a sufi'ici ent quantity of the liquid composition in accordance with the composition to alter the center of gravity of the vessel to the desired degree. As will be clear from the explanation given above, this preselected degree will be dependent upon circumstances, most particularly upon the nature of the cargo and where it is stowed in the ship.

In accordance with a more particular aspect of my invention, the invention may be carried out in two steps, whichcomprises, first, the step of coating the interior surfaces of the empty ballast tanks with a mixture of a corrosion preventing mixture as more fully described hereinbelow, this mixture being effective against the corrosion of steel over indefinitely prolonged periods of time, naturally in the presence of the high-density compositions which are subsequently placed in the ballast tanks; and this corrosion preventive composition furthermore being fully compatible with the said high-density fluids, so that even though they remain in place on the steel surfaces and are from a practical standpoint immiscible with the high-density fluids, they do not adverselyaffect the properties of'the latter even on prolonged contact. After the interior walls have been so coated, the tanks are then filled to any desired degree with the high-density fluid compositions. Common practice generally is to fill sloshing. Individual fluid ballast compartments may of course be leftempty if desired to adjust the ballasting as of course is commonplace. a

The environment of the invention process may be seen in the drawings, in which FIGURE 1 is a partially schematic cross-section of a ship taken amidships, and transversely to the long axis of the ship. designates the hull of the. ship, while 11 is a representative intermediate deck. 12 designates containerized cargov placed above the upper deck while 13 designates containerized cargo in the hold,.or-normal cargo-carrying space in the vessel. 14 designates the false bottom of the ship and 15 the actual bottom, with the ballast tank space 16 intermediate therebetween.

The center of gravity of the cargo is indicated by the, point 17, and the center of gravity of the cargo and the ballast under proper conditions of ballast is shown by the point 18, which is below the water line 19.

In keeping with common practice, the ballast tank space. 16 is sectionalized by a number of longitudinal partitions 20, whichare intersected by transverse partitions 21. Both of these partitions have apertures, such as 22 and 23, which in general are large enough to permit a man to climb through for the purpose of inspection, repair, and the like;.and smaller apertures 24 and 25 areprovided at the top and bottom respectively of the partitions, so that the ballast fluid may flow freely into thetank section. A covered hatch 26 is shown to permit entry into the tank section.

When my invention is carried out with the precoating step set forth hereinabove, I first coat the interior of the ballast tanks with a mixture of an oil-soluble organic nitrogen basecorrosion inhibitor and an oil-soluble pitch, which forconvenience in application I generally dilute witha petroleum solvent such as kerosene or Stoddard solvent. The oil-soluble organic nitrogen base corrosion inhibitor may be selected from alarge number of commercially available preparations corresponding to this description. I prefer to use the particular material available under the trade name of Ethoduomeen T13, which has the following structural formula:

R.NCH2CHzCHzCHz N-( 011 011 0) xH (CHzCHzOhH (CHQOH)yH where R is'a tallow fatty acid chain, and x plus y plus 2 is 3. It will be observed that this is a monolong-chain alkyl, triethoxylated polymethylene diamine.

Alternatively, other long-chain substituted oil-soluble organic nitrogen base corrosion inhibitors can be used, such as the analogues to Ethoduomeen T-13 corresponding to the above formula but having x plus y plus z equal to 4, 5, or 6, and the like; and also with R'being C2 or C chains. Further, substituted amines generally eontaining at least one long-chain alkyl radical of from twelve to twenty-two carbon atoms are usable in my invention; specific examples are octadecyl amine; dioctadecylmethyl amine; dioctadecyl dimethyl amine; l-hyd-roxyethyl, 2-heptadecyl imidazioline; and the like. Also, of course, mixtures of any of these may be employed.

For the oil-soluble pitch, I may use a natural or a blownasphalt or a pitch of vegetable origin such as tall oil pitch or a fatty acid pitch such as soya pitch or cotton-seed pitch. I prefer the last. These two materials are used in relative proportionsof from 2:1 to 1:2; I prefer 42 percent by weight of the oil-soluble organic nitrogen base corrosion inhibitor and 58 percent by weight of the pitch. A convenient consistency for applicationto the ballast tanks is achieved by diluting the mixture each tank or separate tank section full so as to avoid with the ballast fluid.

When using a mixture of the type just described for coating the ballast tanks, it will be found that about one 'bentonite used is about 16.2 lbs.

gallon of the mixture per square'feet of coated surface is a convenient rate of application, and may be readily'accomplished with a heavy duty spray gun, a brush, or a paint roller.

Theballast tanks having been coated in the fashion just described; or alternatively without first coating the ballast tanks, in the event that it is deemed unnecessary in the particular circumstances, I then fill them to the extent necessary to achieve the preselected amount of alteration in the center of gravity of the vessel with a liquid composition as already set forth.

Where the gelling agent is bentonite, I have found that a suitable amount thereof to yield a liquid composition of pump-able consistencyand yet one which does not permit settling out or sludging of the solids may be determined by a simple formula. It is equal to about 6400 over the number of pounds of barite used for each barrel plus 2; or, in algebraic form, where B is the said number of pounds of barite, itis equal to 6400/ B plus 2. Thus, if 450 lbs. of barite are used, the amount of It will be understood, of course, that slight variations about these ideal proportions are permissible in all cases; a pilot test can readily be made using the particular barite, bentonite, water, and other ingredients which are at hand in any given instance. These remarks apply also to the amount of sodium humate as discussed below.

Where the selected deflocculating agent is sodium humate, the amount to give the best composition known to me is about of the difference between the weight of barite used per barrel and 450; in algebraic form, this is 13-45 0/100 in pounds. Thus, where the amount of barite is 450 lbs. per barrel, no sodium humate need be used; where the amount of barite is 650 pounds, then I use about 2 lbs. of sodium humate per barrel and similarly for intermediate amounts. As already noted, the amount of water used is simply that necessary to complete the barrel of 42 gallons and may be computed from the known densities of the separate ingredients. Moreover, specific examples are given below.

Optionally, particularly where the composition may remain in place in the ballast tanks over a very long period of time, I prefer to include in the composition from about /2 to about 2 pounds per barrel thereof of a bacteriostatic agent which is preferably selected from the class consisting of paraformaldehyde; glutaraldehyde; substituted phenols, e.g., cresol; chlorinated phenols, e.g., pentachlorophenol; and mixtures thereof.

To give some specific working examples of the liquid ballast fluids which I use, and which it will be clear form by themselves a valuable aspect of my invention, I give the following compositions, all for one barrel:

Component Ex. 5 Ex. 6 EX. 7 Ex. 8

Water, bbl 60 60 60 60 Wyoming Bentonite, l 13 13 13 13 Ground Barite, lb. 580 580 580 580 Paraformaldehyde, 1b 1. 1. 0 Glutaraldehyde, 1b. 1.0 Pentachlorophenol, 1b 2.0 Tetra Sodium Pyrophosphate, 1b- Sodium Amino Methylphosphonate,

lb 0. 1 0. 1 0. 1 Density of Fluid, lb./ou. it 140 140 140 140 The density of the ground barite used in the above example was 4.30. This may vary as already noted, within the commercial range which is obtained, which is about 4.20 to about 4.35. All of the fluids of the above examples exhibited complete stability upon long standing, even with intermittent vibration, without any sludging, separation of solids or separation of free water at the top. Moreover, they were microbiol-ogically inert, and furthermore, were completely compatible with the mixture of oil soluble organic nitrogen base corrosion inhibitor and oil soluble pitch, as already described.

It will be observed that the objects of my invention have been accomplished in accordance with the foregoing. Furthermore, it is to be noted that my invention is a broad one and while I have described it with the aid of numerous specific examples, nevertheless, much variation-is possible in the details without departing from the spirit as delineated from the claims which follow.

Having described my invention, I claim:

-1. The process of altering the center of gravity of a vessel having liquid ballast tanks therein which comprises the step of filling into said ballast tanks, in a quantity suificient 'to alter said center of gravity by a preselected amount, a liquid composition consisting essentially of water; ground barite in a quantity sufficeint to impart a density from about to about pounds per cubic foot to said composition; a gelling agent in a quantity sufiicient to inhibit settling of said barite; and a deflocculating agent in a quantity sulficient to prevent excessive gel-ation of said gelling agent upon long standing.

2. The process in accordance with claim 1 wherein said gelling agent is bentonite and said deflocculating agent is chosen from the class consisting of Water-soluble humates, Water-soluble lignosulfonates, and Water-soluble polyphosphates, soluble amino-methylphosphonate salts and mixtures thereof.

3. The process in accordance with claim 1 wherein said composition contains from about /2 to two pounds per barrel of said composition of a bacteriostatic agent selected from the class consisting of paraformaldehy de, glutaraldehyde, substituted phenols, chlorinated phenols, and mixtures thereof.

4. The process in accordance with claim 1 wherein said filling step is preceded by the step of coating said ballast tanks with a mixture of an oil-soluble, organic, nitrogenbased corrosion inhibitor and an oil-soluble pitch.

5. The process in accordance with claim 4 wherein said corrosion inhibitor is a mono long-chain alkyl, triet-hoxylated polymethylene di-amine.

No references cited.

MILTON BUCHLER, Primary Examiner. T. M. BLIX, Assistant Examiner.

Claims (1)

1. THE PROCESS OF ALTERING THE CENTER OF GRAVITY OF A VESSEL HAVING LIQUID BALLAST TANKS THEREIN WHICH COMPRISES THE STEP OF FILLING INTO SAID BALLAST TANKS, IN QUANTITY SUFFICIENT TO ALTER SAID CENTER OF GRAVITY BY A PRESELECTED AMOUNT, A LIQUID COMPOSITION CONSISTING ESSENTIALLY OF WATER; GROUND BARITE IN A QUANTITY SUFFICIENT TO IMPART A DENSITY FROM ABOUT 125 TO ABOUT 150 POUNDS PER CUBIC FOOT TO SAID COMPOSITION; A GELLING AGENT IN A QUANTITY SUFFICIENT TO INHIBIT SETTLING OF SAID BARITE; AND A DEFLOCCULATING AGENT IN A QUANTITY SUFFICIENT TO PREVENT EXCESSIVE GELATION OF SAID GELLING AGENT UPON LONG STANDING.

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