3) failure of personnel to observe filling of auxiliary and special ballast tanks, torpedo tubes, missile tubes, etc.; 4) blowing of the negative tank at the wrong time. b) Submerged: 1) penetration of water in the pressure hull; 2) failure to periodically adjust the trim and drain the bilges and special tanks; 3) spontaneous filling of the annular spaces of the torpedo tubes, tanks, missile tubes. A loss of buoyancy, not accompanied by the appearance of trims, can result from compression of the pressure hull at great depths or during passage of the submarine into an area with a lower water density. In event of uncontrolled and increasing trims during diving (immediately after the midship ballast tanks are filled) or in event of accident while submerged, due to penetration of water in the pressure hull, the submarine should immediately surface if the tactical situation permits. In operating submerged, if there is an increase in trim by the head caused by jamming of the planes in diving position, the following steps must be taken immediately: reduced; 1) blow the forward ballast tanks under high pressure until the trim is 2) go astern, if need be increasing the speed to the maximum possible in order to overcome diving inertia and to prevent the submarine from plunging. From the beginning of reduction in trim, periodically (every hour) remove a bubble from the forward ballast tanks, not permitting the decrease in trim to accelerate or to pass abruptly through zero; 3) with a reduction in trim to zero, to go ahead, if need be increasing to full speed so that the submarine can be controlled using the remaining pair of properly operating diving planes. In order to counteract spontaneous surfacing of the submarine with trims by the stern, caused by jamming of the planes in surface position, in the majority of cases all that is needed is to decrease speed or to stop. In operating submerged, if a trim by the head develops, caused by penetration of water in one of the forward compartments, the following steps must be taken immediately: 1) blow the forward ballast tanks under high pressure until there is a decrease in trim; 2) increase to maximum speed, adjusting the planes for diving at full throw in order to produce a trim by the stern and to maintain it within required limits. In reducing trim it is necessary to periodically (every hour) remove excess air from the forward ballast tanks, without permitting acceleration of increasing trim and an abrupt shift to trim by the stern. In every case an air cushion should remain in the blown tanks, approximately equal to the volume of the flooded portion of the compartment. As the trim approaches zero, the following measures must be taken if the submarine continues to dive: 1) blow the midship ballast tanks until the submarine begins to rise; 2) maintain the trim and surfacing speed within required limits by changing speed, the diving plane angles and the volume of the air bubbles in the ballast tanks. If a trim by the stern develops under way, as a result of penetration of water into one of the after compartments, the following steps must be taken immediately: 1) begin partial blowing of the after ballast tanks, continuing until there is a decrease in trim; 2) increase the speed as required and set the planes for diving in order to overcome the increasing trim and to reduce it to the required level as determined by the weight of water taken on and the lever arm of the flooded compartment. In reducing the trim, the excess air must be removed periodically (every hour) from the after ballast tanks, while preventing the decrease in trim from getting out of control and preventing the development of a trim by the head. In each case an air bubble should remain in the blown tanks, approximately equal to the volume of the flooded portion of the compartment. If in the process of decreasing the trim the submarine continues to dive, blowing of the midship ballast tanks must be started, continuing until the submarine begins to rise. If this measure produces a significant reduction in the rate of decrease in trim, the after ballast tanks must be blown again. As the trim approaches the required amount for the given case, the following steps must be taken: 1) resting assured that the stern is "light" and that the decreasing trim can achieve the required value, remove once again the excess volume of bubble from the after ballast tanks; 2) maintain the required surfacing rate with the best possible trim by varying the speed, diving plane angles and the volume of the air cushions in the ballast tanks. If under the circumstances of the situation a damaged submarine cannot surface, then after compensating for acquired negative buoyancy and the trimming moment resulting therefrom, the submarine is kept within a given depth range by varying the speed, diving plane angles and the volume of the air in the main ballast tanks. 9. Handling a Submarine in Fresh Weather Maintaining a submarine at periscope depth with a state of the sea of 4-5 and higher is quite difficult, since in this case an additional buoyancy force is acting on the submarine, created by the heavy sea. This force is created by the warping of equal-depth surfaces in the mass of water affected by wave action, producing a change in pressure gradients with depth, whereby the pressure gradient decreases under the crest of a wave, and increases under the trough of the wave. This increase is greater than the decrease under the crest. This results in heels and trims, hindering control with the diving planes. In individual cases an increase in trim by the stern increases the submergence depth of the submarine or will cause it to broach. A negative buoyancy of 3-5 tons (depending on the class of submarine), which can be compensated for by operating the diving planes and increasing the speed, must be imparted in order to avoid broaching. Periscope depth must be maintained with a trim of 1-2° by the head, making it possible to use the vertical component of the hydrodynamic forces on the hull (which in this case will be downward) to control the submarine. If, despite measures taken, the submarine cannot be maintained at periscope depth and displays a tendency to rise with a trim by the stern, the speed must be increased immediately and the negative tank filled. The latter is blown under high pressure upon reaching a depth somewhat greater than periscope depth, thus making it possible to maintain the submarine at the ordered depth. In rising from this depth to periscope depth, precautionary measures must be strictly observed. 10. Handling a Submerged Submarine in a Turn When a submarine moves in its turning circle there is complex flow of water around its hull. In this case a significant longitudinal hydrodynamic moment and a downward hydrodynamic force arise. Ordinarily in a turn a submarine is maintained with a slight trim by the stern. It is not practical to adjust the trim by pumping water between trim tanks, since the turn is of short duration. In order to maintain the ordered depth in turning, both sets of diving planes must be set for diving before beginning it. The bow planes must be set at a larger angle than the stern planes. If however the submarine begins to rise, the speed must be increased and the negative tank filled. The latter is blown as soon as the submarine begins to dive. As the speed is increased the maximum trim angles should be decreased. 11. Handling a Submarine When the Diving Planes Break Down When the bow planes break down, it is possible to handle the submarine with the stern planes, which merely require resetting to a larger angle. Whenever the diving planes break down, the trim must be adjusted from a calculation of the ordered speed. If the bow planes are jammed in surfacing position, the positive vertical component must be compensated by taking sea water into the forward trim tank and continuing handling with the stern planes. If the bow planes are jammed in diving position, part of the water must be pumped out of the forward trim tank. If the stern planes are jammed, control must be maintained with the bow planes. In order to compensate for the lift force and trim created by the stern planes, the trim must be adjusted. If the stern planes are jammed in diving position, part of the sea water must be taken into the after trim tank. If they are jammed in surfacing position, water must be pumped overboard from the stern. If both the stern and bow planes are out of commission, the submarine is maintained at the ordered depth by varying buoyancy or speed, or by using a depth stabilizer. In order to create positive buoyancy and stabilize the submarine with a rapid increase in trim, the main ballast tanks (fore or aft, as the case may be) and midship tanks must be blown. Moreover, with an increase in trim by the head, the submarine goes at full speed astern and, with trim by the stern, full speed ahead. If in a submarine the trim by the stern increases in running ahead, then in event of a rapid rise the negative tank must be filled. 12. Handling a Submarine Bottoming and Bottoming of a submarine may occur under way and while dead in the water at depths ranging from a safe depth to operating depth. The bottoming site is selected according to the nature of the bottom. Bottoming on solid rock or a rocky surface is not permitted, in order to avoid damaging the tanks or kingstons. The log is shipped and the fathometer housed before bottoming. Bottoming without a way on. After personnel proceed to their stations with the command "Proceed to your stations, bottom," a slight negative buoyancy is created, the submarine is trimmed up to 2° by the head, and the electric motors shut off. The submarine should submerge slowly. If diving stops, sea water must be taken into the negative tank (200-250 liters). The moment of contact with the bottom is determined from the depth gauge needle, fathometer readings and a decrease in trim by the stern. In bottoming at great depths, a submarine acquires additional negative buoyancy from compression of the hull, with a resulting increase in diving rate. Therefore, in order to decrease the diving rate, in some cases some of the water must be pumped out of the negative tank. Bottoming with a way on. After the command is given and personnel proceed to their stations, a slight negative buoyancy is created, the submarine is trimmed up to 2° by the head and runs at slow speed. About 10-15 m above the bottom the electric motors are turned off and the submarine, with a trim by the head of approximately zero, should dive slowly under the sole influence of its slight negative buoyancy. The moment at which bottoming occurs is determined from little bumps or scrapes on the bottom, from readings on the fathometer and depth gauge, and also from the decrease in trim by the stern. In order to keep the submarine stable on the bottom, water must be taken into the negative tank and this fact recorded in the rough deck log. 13. Handling a Submarine Bottoming on a Thermal Layer Bottoming of a submarine on a thermal layer can occur while dead in the water or with a way on, both at periscope depth and at depths ranging from safe depth to operating depth. Bottoming without a way on. Upon entering an area with a liquid bottom, the engines are stopped and slight negative buoyancy created, so that the submarine dives slowly. When a liquid bottom is penetrated the depth gauge needle stops and there is a reduction in trim. Bottoming with a way on is done if the location and depth of a layer of liquid bottom are unknown. In bottoming, it is necessary to proceed at slow speed, create a slight trim by the head (or stern) and carefully observe the depth gauge. Entry of a submarine into a liquid bottom layer is indicated by the following: in diving, a cessation of diving and a reduction in trim; in surfacing, an acceleration in surfacing and an increase in trim. When the submarine enters a layer of liquid bottom, it must be stopped and must wait until a constant depth is established. As a rule, passage through a thermal layer should be made with a way on and with a trim. While lying on a liquid bottom, the depth gauge needle and trim of the submarine must be carefully observed in order to make sure that the submarine may get under way at any time and maintain depth. In order to rise from a liquid bottom, it is necessary to proceed at slow speed, develop a slight trim by the stern (or head) with the diving planes and rise to the ordered depth. 14. Handling a Submarine In Anchoring and A submarine may anchor under water either with a way on or lying dead in the water. The following measures must be taken to anchor dead in the water: 1) select an anchorage site; 2) trim the submarine, with a slight trim by the head; 3) let out the anchor chain with an electric motor to a depth equal to the difference between the depth of the sea and the depth of the anchorage; 4) develop a slight negative buoyancy by taking water into the negative tank so that the submarine gradually submerges. As soon as the anchor lies on the bottom, there is a decrease in trim by the stern and the submarine acquires positive buoyancy. In order to eliminate part of this positive buoyancy, sea water must be taken into the forward trim tank in |