Ballast tank

“ Quick-opening valves are opened and the water rushes into the ballast tanks and superstructure at the rate of fifty or sixty tons per minute. The order is then given: "Trim for submergence!" Sufficient water is then admitted into the final adjustment and trim tank to give the desired buoyancy and trim, and the vessel is now ready to submerge on signal from the commander, who now takes his station at the periscope. The gunners have also taken their stations at the torpedo tubes to prepare to load the tubes as soon as the torpedoes already in the tubes are discharged. ”

“ The amount of fuel supplied to any one of the motor units can likewise be controlled from a central board, and this is also true of the ballast release apparatus, so that water can be emptied from any one of the ballast tanks at will, thus facilitating ascent or descent by lightening one end or the other. Elevating and steering surfaces are operated by small hand-steering wheels with cables passing around their drums, a member of the crew being stationed at each of these controlling wheels. ”

“ The Ballast Pumps and What They Do.—The pumps which pump the water from the ballast tanks are driven by electric motors. They must be powerful pumps, for they not only have to pump the water out of the tanks quickly, but they have to force it out against the pressure of water in which the submarine is submerged; this pressure increases the deeper the boat sinks, and it is often 80 pounds or more to the square inch. The pumps are controlled from the conning tower, and also from the navigating compartment. ”

“ Variations in weights are so important to the submersible that, as fuel is used, water is allowed to enter certain tanks to compensate exactly for the loss of the weight of the fuel. To obtain such an equilibrium, an automatic device controlled by the pressure of the water, which, of course, varies with the depth, is used. This device controls the pumps which fill or empty the ballast-tanks, so as to keep the relation of the submersible to the water which it displaces constant, under which condition the vessel maintains a fixed depth. ”

“ Her net register is 2245 tons, her dead-weight capacity 8400 tons, and her measurement 11,000 tons. Her topside tanks contain 1350 tons, and her total water-ballast is 3200 tons.
In the steamers built by Messrs. William Gray and Co., Ltd., of West Hartlepool, water-ballast is carried not only in the double bottoms but in side tanks, the inner skin of the double bottoms being carried a considerable distance up the sides. A hull within a hull is thus formed, the intervening space being used as water-ballast tanks. Not [348] the least advantage is the great additional strength the ship is given. ”

“ If she were built like an ordinary ship and simply fitted with ballast tanks, she would sink when these are filled with water and never come up again, for her natural buoyancy would be destroyed. As it is, a submarine has tanks filled with air which keeps her buoyant, and these will bring her to the surface the moment the ballast tanks are empty. ”

“ Now we are rising to the surface. By the use of the rudder the boat pushes forward faster and faster to the surface of the water. In order to accelerate the ascent compressed air is forced into one of the submersion tanks.
Now she moves very rapidly: the tower is already free. The deck rises dripping out of the water, the conning-tower hatch is opened, fresh air streams in, and I give the command:
"Blow out ballast tanks!"
A wild howling and screeching comes in reply from the control-room, while the powerful turbine engine presses the water out from the submerging tanks. ”

“ When water is pumped into the ballast tanks in order to make the submarine settle down, the air which normally fills these tanks is compressed into a fraction of its proper space, and is therefore always exerting a downward pressure which increases as more water is pumped in. ”

“ Her water-ballast tanks can be emptied or filled as fast as the cargo is placed in her or taken out. She was built by the Doxford firm at Sunderland for a Newcastle Shipping Company.
The carrying of petroleum in bulk has spread enormously of late years in both steamers and sailing vessels specially designed for the purpose. In all such vessels the method of the subdivision of the holds into tanks is of the greatest importance, together with that of ventilation, and every builder and owner of such vessels has his own theories as to the best means to be adopted. ”

“ We found that we did not have sufficient ballast to enable her to be submerged by filling the usual water ballast tanks, so we had to let some additional water in her motor-room, being careful not to let it rise high enough to saturate the windings of our dynamo-motors. In the meantime the storm had been increasing in velocity and a very rough sea had arisen. I had observed through the sighting hood that the tender was making very bad weather of it ”

“ The foremost one is the usual collision bulkhead. Between this and the foremost engine room bulkhead are Nos. 1 and 2 holds, separated by a watertight bulkhead. Abaft the after engine room are two more holds, divided in the same manner as the forward ones, and astern is another compartment, in which all stores are kept. Coal bunkers form a protection for the engines and boilers. Fore and aft the ship, as low down as possible, are a number of ballast tanks, which can be filled with or emptied of water as occasion requires to alter the trim of the ship. ”

“ A new feature was the use of piano wire for the support of the car, thus greatly reducing the resistance of the air which in the case of the old cord suspensions was almost as great as that of the balloon itself. Another novel feature was water ballast tanks forward and aft on the balloon itself and holding together twelve gallons. By pulling steel wires in the car the aviator could open the stop-cocks. The layman scarcely appreciates the very slight shift in ballast which will affect the stability of a dirigible. ”

“ The small amount of water which leaks through each time is caught by drain pipes and a compressed air pump instantly expels it. As each torpedo is expelled a buoyancy regulator will open the sea cocks and let enough water in the ballast tanks to make the buoyancy uniform and keep the boat at the same distance beneath the surface. ”

“ The "outer tanks," therefore, have no connection with the floating capacity of the boat; they are only the result of the outer construction which above water does not follow the line of the heavy hull and tanks. In spite of their relatively unimportant functions the "outer tanks" must, of course, be accessible from the upper parts of the vessel. This is made possible by large movable steel lids and by ladders on the upper surface of the deck. Standing on the so-called tank-deck, therefore, you have a slight elevation to the upper deck surface. ”

“ Instead of two thousand tons of dead-weight in coal, the steamer may carry four hundred. In carrying and consuming large quantities of coal, the matter of ballast is a serious consideration. A hydrocarbon liquid, carried in several tanks, would be expelled therefrom to the furnaces by pumping water into the tanks, the ballast remaining nearly the same.’ There can be no question that such fuel is eminently suited to fast-sailing cruisers, which may be required to remain at sea for lengthened periods, without touching at port. ”

“ One does not know what is happening outside his little steel prison. One often cannot see where the machine is going. The noise inside is deafening; the heat terrific. Bombs shatter on the roof and on all sides. Bullets spatter savagely against the walls. There is an awful lack of knowledge; a feeling of blind helplessness at being cooped up. One is entirely at the mercy of the big shells. If a shell hits a tank near the petrol tank, the men may perish by fire, as did Gould, without a chance of escape. Going down with your ship seems pleasant compared to burning up with your tank. ”

“ And it is this ponderosity, with its slow but resistless movement, that gives the tank its power.
The tank, by means of the endless belts of steel plates, can travel over the roughest country. It can butt into a tree, a stone wall, or a house, knock over the obstruction, mount it, crawl over it, and slide down into a hole on the other side and crawl out again, on the level, or at an angle. Even if overturned, the tanks can sometimes right themselves and keep on. At the rear are trailer wheels, partly used in steering and partly for reaching over gaps or getting out of holes. ”

“ The weight of the engine, to port in the models, would have to have been counteracted by ballast to starboard. Due to the coal bunkers, and the possibility of two boilers below the engine in the hold, there would not have been room for sufficient ballast. In addition, were such ballasting possible, the combined weights were too far forward to give proper trim, and a great deal more ballast would have been required far aft, a most impractical proceeding. ”

“ Two years subsequently Messrs A. M‘Millan & Son, Dumbarton, introduced water ballast into one of the largest class of sailing vessels then being built. Unlike previous sailing ships with provision for water ballast, however, the vessel was constructed on the structural cellular bottom principle, having bracket floors and continuous girders, as so generally approved in steamships. Capacity for water ballast, to the extent of over 300 tons was thus provided, the filling and discharge being effected by a special donkey engine, supplied with steam from a large donkey boiler. ”

“ Beginning at the entrance—the most conspicuous objects are life-belts and buoys, coils of rope on the walls, fishing-rods, and a home-made lobster pot; under foot is the water-tank, capable of holding 3,500 gallons, the walls are 9ft. thick at this point, and the gun-metal doors weigh a ton, thus massively constructed in order to withstand the shock of heavy seas.
Thence, by a flight of sixteen steep iron steps (a similar flight connects each room) , we proceed to the next compartment, where, as well as in that above it, is kept the mainstay of the light. ”

“ Petrol was supplied to the engine in the earlier days of the Mark IV machine by a pressure-fed system which gave a great deal of trouble, and, being also considered dangerous, was finally discarded in favour of the Autovac system, which sucked the fuel from the main supply in a tank outside of the machine and delivered it to the carburetter by gravity. ”

“ The engine was not powerful enough. The steam Tank had not in the least answered the riddle. The horse-power could, it is true, be almost indefinitely increased, but, like a kind of Old Man of the Sea, the engine weight would have increased proportionately and the “free” power have been no more.
Indeed till the invention of the petrol engine the Tank was doomed to be unpractical. Its three essentials—armour-plating, guns, and ability to surmount obstacles and traverse open country—demanded a large amount of this “free” power. ”

“ In a tickle boat like a submarine, it is necessary to have some means of trimming the vessel, fore or aft, at any moment, and especially when about to dive, or when caught by some under-water obstruction. Tanks are therefore fitted for this purpose at each end of the boat. They are comparatively small, because the effect required is in ordinary circumstances very limited, and in a desperate emergency they may need to be supplemented by rushing the crew fore or aft, as living ballast. ”

“ Either the ground in front of the three cupolas was mined, or else a deep pit, with vertical sides, had been dug, and concealed by means of a covering of boards strong enough to bear the weight of a few men but unable to withstand the 200 tons dead weight of a Tank.
With one tractor band grinding ahead and the other reversed the Tank made a half turn in its own length and commenced to cross the front of its objective. Then climbing the rising ground with consummate ease the mammoth charger drew up to the flank of the machine-gunners' lair. ”

“ Around each outer edge runs an endless belt of steel plates, hinged together, with ridges at the joints, and these broad belts of steel plates, like the platforms of some moving stairways used in department stores, moving around, give motion to the tank.
Inside, well protected from the fire of enemy guns by steel plates, are the engines for driving the belts, or caterpillar wheels, as they are called. There is also the steering apparatus, and the guns that fire on the enemy. There are cramped living and sleeping quarters for the tank's crew, more limited than those of a submarine. ”

“ Much of the canal bridging and of the track making was done under fire, shrapnel, gas and H.E.
Often a series of shells, bursting on the newly laid causeway would undo a day’s work in a few minutes. Half the time the men had to wear gas-masks, and almost always they worked knee-deep in liquid mud or in the oozy bed of some little “beke.”
Yet in no instance did the 184th Tunnelling Company fail to carry out the work allotted to it.
One very ingenious piece of mechanism for use on the Tank itself had been evolved at Central Workshops in view of the Flanders mud. This was the “Unditching Beam.” ”

“ The James River is mined with fifteen tanks below the iron battery at Chapin’s (Chaffin’s) Bluff. They are to be exploded by means of electricity. Four of the tanks contain 160 pounds of powder; the eleven others hold 70 pounds each. All are made of boiler plate. They are arranged in rows as per diagram, those of each row being 30 feet apart. Each tank is contained in a water-tight wooden152 cask, capable of floating it but anchored and held below the surface from three to eight feet, according to the state of the tide. ”