US3219006A - Tanker - Google Patents

Description

Nov. 23, 1965 Filed Jan. 3, 1964 FIG.

FIG.2

H. VREEDENBURGH 3,219,006

TANKER 2 Sheets-Sheet 1 INVENTOR.

HE RMAN VREEDENBURGH.

BY W/A, ATTORN 1965 H. VREEDENBURGH 3,219,006

INVENTOR. HERMAN VREEDENBURGH ATTORNEY.

United States Patent 3,219,006 TANKER Herman Vreedenburgh, Viaardingen, Netherlands, assignor to Phs. van Ommeren N.V., Rotterdam, Netherlands Filed Jan. 3, 1964, Ser. No. 335,648 Claims priority, application Netherlands, Jan. 9, 1963, 287,607, 287,608; Mar. 1, 1963, 289,695 3 Claims. (Cl. 114-74) The invention relates to a sea going ship for transporting liquids, provided with tanks mounted inside the ship.

Up to now such tankers were provided with a relatively large number of tanks, giving the possibility to solve rather easily the problems related to charging desired combinations of different types of cargo, whilst retaining a good trim of the ship under different load conditions and a regular distribution of mechanical stresses along the length of the ship, so that vertical bending moments are reduced to a minimum.

Serious difficulties arise, however, if one tries to comply with the above indicated desires with a ship being provided with only a relatively small number of tanks. On the other hand a small number of tanks has important advantages with respect to pumping and duct systems, the ships weight, construction cost and maintenance.

The invention aims at providing a solution making it possible to reduce the number of tanks drastically and nevertheless to fulfill the above desires, so that the indicated advantages related to a small number of tanks can be realised without entailing the disadvantages thereof.

The invention provides a tanker having an odd number of tanks placed one behind the other in the longitudinal direction of the ship, at least two of these tanks having a first or greater length and the remaining tanks having a second or smaller length, the smaller length being half or approximately half of the greater length and the number of tanks having the smaller length being two or more.

Though the rules for tankers in different countries and formulated by ditferent classification authorities are not completely identical, there is, at the present moment, in general an objection against providing liquid tanks having a length of more than 20% of the ships length.

Because the cargo carrying portion proper of the ship (thatis the portion between the fore and stern parts of the ship, which portion in many instances is separated from these fore and stern parts by the colferdams) generally takes up about 70% of the ships length, the minimum number of cargo tank-s, when applying the invention, is five.

Accordingly, an embodiment of the invention provides a tanker in which the cargo carrying portion proper of the ship contains two cargo tanks having a length of approximately 20% of the ships length and three tanks having a length of approximately of the ships length.

An important advantage of the invention is that, when only partly loaded, a ship according to the invention can be readily trimmed whereas the mechanical stresses due to the cargo can be evenly distributed. Of course trim and mechanical stress are also dependent on the ballasting facilities of the ship, but the tank plan of the invention enables a good trim and even cargo distribution without necessitating to divide the cargo athwartships, for instance by placing a number of cargo tanks side by side, which with certain load configurations are not all filled with liquid cargo.

In this specification the terms about of the ships length or 20% indicate a percentage of the ships overall length, that can only very slightly exceed the exact value of 20%, not only because it is very Patented Nov. 23, 1965 improbable that the related rules will be changed, but also because tankers having a cargo carrying portion proper, that is longer than 70% of the ships length, practically do not exist. At its lower side the value about 20% of the ships length or 20% is limited by the fact, that the length of the tank has to correspond to or less of the cargo carrying portion proper, so that for instance in case of a length of the cargo carrying portion of 65% of the ships length, which is a low value, the tank length 'of about 20% will equal 18.6% of the ships length. Consequently the term about 20% of the ships length is used for indicating a value between 18% and 20% or very little more than 20% of the ships length. The term 10% of the ships length or 10% means half of this.

A good cargo distribution for a partially loaded ship is possible when according to a further embodiment of the invention the sequence of tank lengths is small, large, small, large, small. Then a very small partial load of about 15% of the loading capacity can be carried in the middle tank; a partial load of about 30% in the two small outer tanks; a partial load of about 45% in the three small tanks and a load of about 55% in the two. large tanks. The proportions 85 %15 and 70%-30% are important in practice, so that a ship according to this embodiment of the invention in such practical conditions is a very favourable one.

It is also possible to place the tanks in the sequence: large, small, small, small, large. Then the smallest partial load of 15% can be put into the middle small tank, the partial load of 30% into the outer small tanks and a partial load of about 45% in the three small tanks. In this last intsance the load will induce a marked bending moment, but, when the ballasting facilities allow this, compensation is possible by ballasting. The indicated partial load conditions have the important ad-- vantage that the trim of the ship is always remarkedly good. Further it has been proved that a ship according, to the invention advantageously can be provided with ballast tanks at both side walls, in which instance a ship according to the invention preferably is provided with three ballast tanks of about 20% and one ballast tank of about 10% along each side of the cargo carrying portion proper.

In many instances it is advantageous to place the small ballast tanks foremost.

Another favourable distribution is first two ballast tanks of about 20% near the foreside, then a ballast tank of about 10% and finally one of 20% at each side wall.

A further advantage of the invention is that, due to the small number of tanks, each cargo tank can be provided with its own duct connected to the pumping room. The same holds for the ballast tanks, though it may be advantageous to combine some of them, for instance two ballast tanks symmetrically placed with respect to the ships longitudinal centre plane.

A ship provided with such ballast tanks can always be sufficiently ballasted as well without cargo as with partial cargo.

A further embodiment of the invention consists in a sequence of the cargo tanks: small, large, large, large, small.

In this instance a large tank contains about 25% of the ships loading capacity and a small tank 12.5% thereof.

This embodiment is very favourable for transporting partial loads of 25%, 50% or of the maximum. A cargo of25% is preferably placed in the two small tanks, but may be put in the central large tank; a cargo of 50%. in the two outer large tanks, and a cargo of 75 in the three 'large tanks.

In that instance it is possible at each side to have four ballast tanks of equal length.

Because the width of the ship is smaller at the fore side of the cargo carrying portion proper than it is at the stern, the volume of the foremost tank will be smaller than that of another tank of equal length.

In the accompanying drawings some embodiments of the invention have been shown schematically.

FIG. 1 shows a central longitudinal section of a tanker according to the invention.

FIG. 2 shows a horizontal section of the tanker of FIG. 1.

FIG. 3 shows a central longitudinal section of a further tanker according to the invention.

FIG. 4 shows a horizontal section of the tanker as per FIG. 3.

FIG. 5 shows a horizontal section of a third tanker according to the invention.

The tanker schematically shown in FIGURES 1 and 2 contains five Cargo tanks 1, 2, 3, 4 and 5. The tanks 1 and 5 have the same smaller length and the tanks 2, 3 and 4 have each a greater length, that equals two times the length of the tanks 1 or 5. At each side walls four ballast tanks 6, 8, 10, 12 and 7, 9, 11, 13 resp. are placed, each of them having a length equal to the said greater length of the tanks. Half-Way in each cargo or ballast tank of the greater length an anti-wave bulkhead, indicated in the drawing with interrupted lines, has been mounted. Such an anti-wave bulkhead is perforated and may have a lighter construction than a normal unperforated bulkhead.

The tanker shown in FIGURES 1 and 2 can carry a small load of about 25% of the total loading capacity in the tanks 1 and 5. Preferably in that case ballast should be put into the ballast tanks 8, 9, 10 and 11, but if heavy ballasting is desired the ballast tanks 6, 7, 12 and 13 can be filled too. It is pointed out that even a cargo of about 12.5% of the total loading capacity can be carried by using tank 1 or 5 for the cargo and 8-13 inclusive or 611 inclusive for ballasting, so that even in this instance no cargo tank need be used for ballasting purposes. A load of 50% of the total loading capacity can be carried in the tanks 2 and 4. In that case no ballasting is necessary. Finally a load of 75% of the ships total loading capacity can be carried in the tanks 2, 3 and 4.

In all loading conditions depicted in the above, the trim of the ship is remarkably good.

In the embodiment of FIGURES 3 and 4 five cargo tanks 21, 22, 23, 24 and 25 have been indicated. The tanks 21, 23 and 25 each have a length equal to half of the length of each of the tanks 22 and 24. The ballast tanks 18 and 18' have the same length as tank 21. The length of ballast tanks 19 and 19' equal that of tank 22, but the ballast tanks 110, 110, 111 and 111 have each a length equal to that of tanks 22 or 24.

The cargo carrying portion proper of the ship contains the tanks 21 through 25 and the ballast tanks 18, 18', 19, 19, 110, 110', 111 and 111. A colferdam 17 separates the fore peak from the cargo carrying portion. Of course another cotferdam may separate the after peak from this portion. The structural plans of fore and after peak are not typical for this invention and may be conventional. The fore peak contains some fuel bunker tanks and additional ballast capacity; the after peak: the living quarters, engine room, pumping room and further fuel bunker tanks. All these may be of conventional design. some embodiments of the invention it is, however, advantageous to provide the cargo tanks with a separate duct (not shown) leading to the pumping room. With the embodiments of FIGURES 1 and 2 these large tanks 2,

3 and 4 preferably have each their own cargo pump,

whereas the tanks 1 and share the fourth cargo pump. Pumping is then very easy, because all pumps can work Simultanflously, the n y OIHIOI necessary being switching With over from tank 1 to tank 5 (or vice versa) when tank 1 (or tank 5) is empty. Because tank 1 is smaller than half of tank 2, 3 or 4, the higher flow resistance in the duct leading to tank 1 will be compensated, so that the tank group 1 and 5 will be empty at about the same moment as tanks 2, 3 and 4.

Also in the embodiments of FIGURES 3, 4 and 5 it is preferred to allot to each cargo tank a separate duct leading to the pumping room. Tanks 22 and 24 or 31 and may each have their own pump, but for the tanks 21, 23 and 25 or 32, 33 and 34 the facility must be provided for them to be connected to one or more pumps, as is conventional at present. Nevertheless, when using a separate duct for each tank, it is not necessary to have a valve near or in the tanks proper.

A ship according to the invention is (as is almost every known ship) in the longitudinal direction divided by webs. Each tank extends over a whole number of webs, so that the configuration of FIGURES l and 2 can always easily be realized by making the number of web spaces of the cargo carrying portion of the ship equal to a multiple of eight. With the embodiments of FIGURES 3, 4 and 5 this should be a multiple of seven.

Generally no advantage and even a disadvantage lies in making the lengths of tanks 1 and 2 or 2, 3 and 4 of FIGS. 1 and 2; 21, 23 and 25 or 22 and 24 in FIGURES 3 and 4 or 31 and 35 or 32, 33 and 34 in FIG. 5 unequal, but slight deviations may still lead to a ship having important advantages over known ships. It is therefore that such slight deviations are considered to be within the scope of the invention.

In the embodiments depicted in the drawings there is always one cargo tank athwartship. This, however, is not necessary and it is possible to construct a ship according to the invention with, e.g., a longitudinal central bulkhead dividing each of the cargo tanks in two separate tanks.

It is also possible though not preferred, to omit the special ballast tank arrangement. Then it may be necessary to use cargo tanks for ballasting purposes, but the advantages of a good trim are maintained.

What I claim is:

1. A tanker comprising a cargo space consisting of five tanks arranged in the longitudinal direction of the ship, three of said tanks being of equal length and arranged in a row, two of said tanks being of equal length and each substantially half the length of one of said three tanks and positioned one each at the ends of the row of three tanks.

2. A tanker as defined in claim 1 further including an anti-wave bulkhead in each of the longer tanks.

3. A tanker as defined in claim 1 further including ballast tanks between the tanks and the sides of the ship, each of said ballast tanks being equal in length to the length of the longest tanks.

References Cited by the Examiner UNITED STATES PATENTS 1,008,008 11/1911 Caines 114-78 1,263,679 4/1918 Kibele 114-74 1,3 02,547 5/ 1919 Heidenreich 114-125 1,323,920 12/1919 Silley 114-78 1,537,764 5/1925 Good 114-125 1,551,944 9/ 1925 Dickie 114-74 1,895,879 1/1933 Camps 114-78 FOREIGN PATENTS 864,467 4/ 1961 Great Britain.

MILTON BUCHLER, Primary Examiner.

FERGUS S. MIDDLETON, Examiner,

Claims (1)

1. A TANKER COMPRISING A CARGO SPACE CONSISTING OF FIVE TANKS ARRANGED IN THE LONGITUDINAL DIRECTION OF THE SHIP, THREE OF SAID TANKS BEING OF EQUAL LENGTH AND ARRANGED IN A ROW, TWO OF SAID TANKS BEING OF EQUAL LENGTH AND EACH SUBSTANTIALLY HALF THE LENGTH OF ONE OF SAID THREE TANKS AND POSITIONED ONE EACH AT THE ENDS OF THE ROW OF THREE TANKS.

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