Protecting Battleships with Compressed Air 



Should a vessel be torpedoed the inrush of water 

 will be stopped by outrushing air under pressure 



UNCLE SAM'S ships have been turned any event the pressure of the air in the 



into giant diving bells or caissons nearest surrounding intact compartments 



to help protect them from torpedo acts equally in all directions and is liable 



attack. It sounds impossible, but it is not; to make the bulkheads and decks leak, 



for it is merely adaptation of the principle For this reason air at a lower pressure is 



of the air lock. This has 

 been used for many years 

 in sinking underwater 

 foundations or driving 

 tunnels under rivers and 

 even in ship salvage work. 

 The hulls of the ships 

 have simply been divided 

 into a large number of 

 compartments to be filled 

 with compressed air. 



Should one or more of 

 these compartments or 

 chambers be shattered 

 by the explosion of a tor- 

 pedo or mine, the ad- 

 jacent compartments are 

 filled with compressed air 

 until the pressure of the 

 air counterbalances that 

 of the water in the dam- 

 aged section. When this 

 occurs, no more water can 

 flow into the vessel and 

 she may be towed into 

 port or proceed under her 

 own steam if her engines 

 have not been damaged. 



Almost the same con- 

 ditions hold true in or- 

 dinary household work 

 when an empty tumbler 

 is plunged bottom upward into a dish-pan 

 of water. The water enters just so far, 

 until the air trapped in the glass is com- 

 pressed to a point where its pressure equals 

 that of the water. Then no more will enter. 



As shown in the accompanying illustra- 

 tion, the hull of the ship is divided into a 

 great number of compartments. Should 

 one of these be punctured by any means, 

 the ones next it are immediately filled with 

 compressed air until the water pressure is 

 equalized and no more can flow in. The 

 compressed air may or may not come 

 into contact with the water in the damaged 

 compartment, according to whether one or 

 more than one chamber is punctured. In 



s. Serv. 



The wake of the torpedo. It is 

 the only warning which the 

 threatened vessel usually has 



pumped into the adjacent 

 compartments, the pres- 

 sure diminishing as the 

 distance of the chambers 

 from the damaged area 

 increases. In this man- 

 ner, the difference in the 

 pressures in the adjoining 

 compartments is only a 

 few pounds and the bulk- 

 heads and decks are well 

 able to withstand it with- 

 out leaking. 



The use of this system 

 has occasioned very little 

 change in the design of 

 the vessels, for battle- 

 ships always have been 

 divided into many cellu- 

 lar divisions for restrain- 

 ing the inflow of water 

 through damage by col- 

 lision. Again, means for 

 pumping the compressed 

 air into the compart- 

 ments was already | in 

 place in the form of pipes 

 to pump fresh air into 

 and exhaust foul air from 

 the chambers. 



Compressed air is also 

 a common commodity on 

 battleships, being used to run the refrigerat- 

 ing machines, to fire torpedoes as well as 

 charge them and to remove the hot gases 

 from the gun barrels after firing. It was 

 therefore only necessary to provide suitable 

 means for connecting the compressed air 

 supply with the compartment pipes. This 

 did not of course change the design of the 

 inner hull or appreciably increase its weight. 

 The system, the invention of William 

 Wallace Wotherspoon, a New York City 

 engineer, was first installed on the armored 

 cruiser North Carolina. All of our recent 

 battleships have the system, so that our 

 sailors crossing the seas or working in the 

 war zone have a chance against torpedoes. 



