Tanker hull modification

#This invention relates to large ocean going tanker vessels that transport liquid such as petroleum crude or refined oil or other bulk cargoes from a loading port to a destination unloading port and then are required to return to a loading port without cargo, thereby making it necessary to take on ballast on the return voyage in order to sink the vessel sufficiently into the water to adequately submerge the propeller and make the vessel manageable, maneuverable and capable of withstanding wind and waves.

#In the past, tankers have utilized water ballast in cargo oil tanks from which the oil had previously been discharged. The oil which had been emptied from the tanks left an oily residue on the inner surfaces and structural members of the tanks. This oily residue mixed into the water ballast with the result that when the water ballast was emptied from the cargo tanks into the sea to make the tanks available for another loading of cargo oil the discharged oily water ballast became a source of oil pollution of the seas. There is a worldwide effort to stop or minimize this pollution of the seas, and international maritime law relulations to this end are, or shortly will be, in effect.

#Under these regulations tankers and bulk carriers will no longer be able to discharge oily ballast water into the sea. If large tanker vessels must take on ballast seawater, this ballast will be carried in separate or segregated ballast tanks into which no previous cargo oil or other product had been carried, so that when it is discharged back into the sea it will be clean ballast. If the ballast must be taken into cargo tanks under emergency weather conditions when ballast requirements are unusually great so that the ballast becomes dirty and cannot be purified, then the ballast will be discharged into shore tanks. In either case, ballasting a vessel becomes an added operational expense because the ballasting compartments constitute a permanent reduction in cargo space. The expense associated with ballast increases directly with the amount of ballast provided for and handled, which produces no revenue.

#FIG. 1 shows a side view of a tanker with compartments designated only for a ballast.

#FIG. 2 shows a top view of the tanker of FIG. 1.

#FIG. 3 shows a tanker with a cutaway hull.

#FIGS. 1 and 2 show side and top views, respectively, of a tanker hull 10 having a propeller 12 and a rudder 14. The inside of the hull is partitioned into compartments by means of a plurality of bulkheads of which longitudinal partitions of bulkheads 16 and 18 and transverse partitions or bulkheads 20 and 22 are typical. The bulkheads define individual separate compartments, of which the compartments employed for seawater ballast only are designated in FIG. 2. The compartments utilized for fuel oil to power the vessel are also designated in FIG. 2. The remaining compartments of which 24, 26 and 28 are typical, are utilized for payload oil cargo only.

#FIG. 3 shows a side view of another hull 30 with positions A, B, C, D and E indicated along the length of the hull and with FIGS. 3A, 3B, 3C, 3D and 3E indicating the progressively changed cross-sectional configurations of the hull at each of said positions.

#FIG. 3A shows that at its forward section the hull is relatively narrow and sideshells 66 and 68 are curved over substantially their entire depths to enable the hull to break the water with a diminished resistance.