cannot be put in proper operating condition before expiration of the normal charging period, the fourth charging stage is accomplished at a constant current equal to two-thirds of the current in the third stage. The following steps must be taken during charging: 1) carefully observe the amount of current and total voltage of the battery groups; the hydrogen concentration in the battery tanks; and the voltage, density and temperature of the electrolyte in the test batteries; 2) gradually decrease the charging currents as the transient voltages are attained. If a storage battery is charged under stormy conditions, or if in special charging the battery is ventilated using hydrogen combustion systems, the density of the electrolyte in the test batteries is not measured and charging is discontinued when current becomes constant (while maintaining constant voltage) or when voltage becomes constant (at constant current). The completion of charging is determined by the constancy of electrolyte density and the amount of current (or voltage) at the end of the fourth charging stage over a period of 1-2 hours, depending upon the electrolyte density. Whenever a battery is charged without a water cooling system, the mechanical electrolyte mixing system must be turned on for 15 minutes at the end of each second hour of charging and throughout its latter stage of charging. When a water cooling system is used, the mechanical electrolyte mixing system should operate: 1) during the first, second and third stages of charging: for 15 minutes at the end of each hour of operation of the water cooling system (before taking measurements on the test batteries); 2) in the fourth stage: continuously to the completion of charging; 3) after charging (with ventilation of the batteries in the atmosphere or in the engine room): for 15 minutes at the end of each hour of operation of the water cooling system. The temperature of the electrolyte during charging should not exceed the norms established by regulations. If the temperature increases during charging, assuming that transient voltage will not be attained, the charging current must be decreased to two-thirds of the current in the third stage, the mechanical electrolyte mixing system must be turned on and, when the transient voltage is attained, charging is continued at a constant voltage while decreasing the current (if the mechanical electrolyte mixing system is not operating properly, charging is continued with a current equal to two-thirds of the current in the third stage). If prior to completion of charging the temperature of the electrolyte in the test batteries exceeds the maximum established under the existing regulations, charging must be temporarily discontinued, without interrupting intensive ventilation of the battery tanks and (if possible) operation of the mechanical electrolyte mixing system. 2. Forced Charging Forced charging is done whenever under the circumstances there is not enough time for normal charging. Forced charging is permitted only if the mechanical electrolyte mixing system is not operating properly, and is done in two stages. Charging is begun using the current of the first stage indicated in the battery instructions, and is continued at a constant current until transient voltage is attained in most of the test batteries. When transient voltage is attained, the latter is kept constant (second stage) until the completion of charging by decreasing the charging current. In forced charging, the mechanical electrolyte mixing system must be turned on for 15 minutes at the end of each second hour of charging (or at the end of each hour if a water cooling system is operating) and, with a decrease in current to the current strength of the third stage of normal charging, it must be in continuous operation until the end of charging. The completion of forced charging is determined by the constant density of electrolyte and constant current at the end of the second stage for a period of 0.5-2 hours, depending upon the density of the electrolyte. 3. Controlling Hydrogen Concentration Under no circumstances should the hydrogen concentration in the battery tanks and battery ventilation tubes exceed 3%. A hydrogen concentration in the atmosphere in excess of 4% (by volume) constitutes a dangerous explosive mixture of great destructive force, which could easily be ignited not only by an open flame, but also by a highly incandescent object or a spark of any origin. The maximum hydrogen concentration in submarine compartments should not exceed 2.5%. The hydrogen content in the battery compartments during charging, with normal battery ventilation, should be practically zero. The hydrogen concentration in the battery tanks and battery ventilation tubes, as well as in the battery compartments if the hydrogen oxidation instruments are not operating, should be controlled using hydrogen measuring instruments. The hydrogen concentration in the compartments using hydrogen oxidation instruments is controlled by thermometer readings on the test instruments. 4. Ventilating a Storage Battery Storage battery ventilators should be switched on 15 minutes before charging is begun and should operate continuously throughout the entire charging period. If the ventilators must be stopped due to improper operation or damage, charging must be immediately discontinued until another ventilation system is put in operation. If during charging the hydrogen content in the battery tanks or battery ventilation tubes exceeds the permissible level, charging must be discontinued immediately, without interrupting operation of the ventilators, and the bulkhead closures and registers for the entire submarine ventilation system carefully checked. Charging may not be resumed until the causes of the unsatisfactory ventilation are determined and eliminated. If it is impossible to ventilate a storage battery through the battery ventilation (exhaust) shaft, and with the diesels charging and boost charging, the battery must be ventilated in the engine room. If it is necessary for the submarine to crash dive, ventilation of the storage battery is discontinued and greater control over hydrogen concentration maintained. If, with all of the hydrogen oxidation instruments operating, the hydrogen concentration in one of the battery compartments reaches the maximum permissible level, the battery tanks and compartments must be immediately ventilated in the atmosphere. If this is impossible, the following steps must be taken: 1) carefully secure the battery tanks; 2) secure all closures, registers and plugs and pipes leading to and from the bottom tanks; 3) isolate the battery compartments and discontinue switching electrical equipment on and off in these compartments, before ventilating the compartments and tanks in the atmosphere; 4) with a decrease in hydrogen concentration in the battery compartments due to operation of the hydrogen oxidation equipment, transfer small quantities of hydrogen from the tanks into the battery compartments, in no case permitting an increase in hydrogen concentration in the compartments beyond the maximum permissible level; 5) check the hydrogen content (%) every 15 minutes. In order to prevent accumulation of a dangerous concentration of hydrogen in the battery tanks and compartments, the battery must be ventilated in the atmosphere every 3 hours for 15 minutes. This periodic ventilation is carried out each time by special order of the Commanding Officer of the submarine or officer of the watch if the conditions under which the submarine is fulfilling its mission and the situation permit opening of the shaft to ventilate the battery in the atmosphere. If before ventilation of the battery in the atmosphere has begun the hydrogen concentration in one of the battery compartments exceeds the maximum permissible level, the conning tower access hatches, bulkhead doors and ventilation shafts must be opened and the submarine ventilated using natural means in order to decrease the hydrogen concentration. Only then should the ventilators be turned on. 5. Explosion of a Storage Battery If established regulations for the operation and maintenance of submarine storage batteries are not observed, the battery could explode, rupturing the tanks, causing a fire and resulting in seepage of electrolyte. Explosion of a storage battery results from detonation of the explosive mixture accumulating under the battery tank covers, and in the battery ventilation tubes, battery tanks and compartments. The explosive mixture could ignite anywhere on the submarine if the hydrogen content there exceeds the maximum permissible level. If a storage battery explodes and fire breaks out in the compartment, personnel must take the following measures: 1) if the storage battery exploded during charging, the latter must be immediately discontinued; 2) if at the moment of explosion the battery and ship ventilating system were operating, they must be immediately shut off and the appropriate closures and registers secured; 3) if the explosion did not involve all of the storage battery groups, the entire load must be immediately shifted to the undamaged groups and the compartments in which these groups are located must be isolated. In fighting fire, personnel must wear self-contained breathing apparatuses. In extinguishing burning plywood, cork, etc. in battery compartments, foam and carbon dioxide extinguishers may be used, but in such a way that the liquid they discharge will not come in contact with the batteries. Sea water may not be used to extinguish a fire in the battery compartments. Only distilled or fresh water may be used for this purpose. When a compartment is opened after a fire, all precautionary measures should be taken to prevent sparks. Neither the battery ventilators, lights or any other electrical equipment may be turned on until the compartment has been naturally ventilated for at least 12 hours. Personnel first entering a damaged compartment should be wearing selfcontained breathing apparatuses and carrying flashlights. 6. Seepage of Sea Water into Storage Batteries If sea water has penetrated one or several storage batteries and this fact is observed immediately, the following steps must be taken: 1) immediately turn on the battery ventilation and disconnect the flooded battery group from the entire circuit, then disconnect the damaged batteries from the circuit; 2) remove the water which has penetrated the battery tank; 3) remove the upper layer of electrolyte from the flooded storage batteries to the level of the upper edges of the plates; 4) carefully fill the batteries with distilled water. If sea water has simultaneously penetrated a large number of storage tanks, the following steps must be taken: 1) immediately cut off the flooded group from the overall circuit and disconnect it at several points; 2) remove water from the battery tank; 4) draw off the electrolyte. A gas mask must be worn in working with a storage battery filled with sea water. SECTION 12. VISUAL AND ELECTRONIC OBSERVATION 1. Use of a Periscope A periscope has two eyepieces, one of which is used for observation and the other to measure distances. In using the eyepiece for observation, the position of the observer's head must be such that his eye will take in the entire field of the eyepiece without cutting it off at the edges. One of the important factors in good observation is accurate focusing of the eyepiece. To accomplish this, the periscope is focused on a clearly visible distant object and, in the absence of such an object, on a bright, uniformly illuminated background (for example, the sky). The eyepiece is adjusted by rotating the knob until the image of a distant object (or the reticle if there is none) becomes sharp and clearly visible, after which a reading is taken from the scale and recorded so that subsequently the eyepiece can be focused directly from the scale. Periscopes have two types of magnification: a small 1.5-power magnification and a large 6-power magnification. In selecting a magnification, it should be borne in mind that in observation using a periscope with 1.5-power magnification, the visibility of the objects observed appears to be about the same as in observation with the naked eye. The greater the magnification, the greater and more visible the dimensions of the target. This makes it possible to examine the target in greater detail and permits accurate focusing. However, with an increase in magnification the field of view of the periscope is reduced. Considering this fact, in searching for the target when observation is begun, when it is necessary to have a large field of view, a 1.5-power magnification must be used. If the target or some other observed object must be examined in greater detail and a large field of view is not required, it is recommended that a 6-power magnification be used. At night and twilight, as well as with bad visibility, a large magnification must be used. Distances to the target can be measured using the range-finding reticle on the periscope eyepiece, located in the field of view to the left of the vertical cross hair (Fig. 17), and also by using the range finder. The range-finding reticle is divided into mils (1 mil = 3.6'). Each small graduation on the range-finding reticle is equal to 5 mils. In measuring distance to the target using the range-finding reticle of the periscope, the following steps must be taken: 1) focus the periscope on the target in such a way that the cross hairs on the range-finding reticle are superimposed over the target; |