i;x 



THE INDIA RUBBER WORLD 



[Junk 1, 1915. 



Rubber's Vital Part in the Submarine. 



i fT" 1 1 1 E sinister submarine: a two-edged weapon." In 

 this fashion has an expert in subaqueous navigation 



the undei 31 at, and good reason there 



is, indeed, for this characterization. For some years prior 



A Submarine at Fcll Speed, with Only Her Periscopes 

 Showing. 



lo the present World War the submarine stirred the public 

 mostly when some catastrophe overwhelmed it and the brave 

 men in charm- were carried to the bottom and drowned. 

 True, there were instances when some of the crew succeeded 

 in escaping and others were rescued by salving the stricken 

 craft in time, but, as a grewsome rule, the men died at their 

 In our own navy, within the past few weeks, we have 

 had brought home to us the perilous nature of service aboard 

 submarines in time of peace The fatal plunge of the "F-4" 

 has marked the first of such accidents in our flotilla, and this 

 will give us some idea of the hazards courageously faced by 

 the crews of kindred craft of the nations now at war. 



The sea is the submarine- worsl 

 enemy — an ever-present one. For 

 the deeper ii dives into this hostile 

 element the greater the odds 

 against it. The pressure of the en- 

 veloping water that prevails near 

 tin- surface increases with each font 

 of submergence at the rate ol .43 

 of a pound, and this crushing force 

 exerts itself upon every square inch 

 of the boat's body in touch with 

 the sea Suppose the submarine is 



down a hundred feet, then every 

 square inch must sustain a pri 

 of 4.1 pounds and every square Foot 

 will be subjected to a menacing 

 weight of nearly three tons! Now 

 see bow fatal this may prove — tak- 

 ing the ill-fated French submarine, 

 the "Lutin," as an instance. 



While performing exercise manoeuvres off the port of 

 Bizerta in 1906, during which the craft probably submerged 

 -ore than 60 suddenly plunged ami sank to the 



bottom in water US feet deep, drowning everyone inside ol 

 her. The cause of tin catastrophe was a stone no larger 

 than a nut. which had unknowingly prevented the complete 



closing oi a sea valve in one of the ballast tanks. The walls 

 of this tank wire not intended to withstand the direct pres- 

 sure of the sea, and with the valve even slightly open this 

 bursting force became too great at the manoeuvring depths. 

 The steel plates yielded, letting the burden of water into 

 adjacent tanks, and before the commander was aware of it 

 the dead weight of his boat was too great; she dropped to 

 the bottom like a stone, her batteries were flooded, asphyxial 

 ing gases generated, and the crew was overcome. 



The purpose of the submarine is to approach her target 

 unobserved and in broad daylight to do that which is well-nigh 

 impossible for the speedy surface torpedo boat. The sub- 

 marine, by sinking beneath the waves, clothes herself for the 

 time being with the water's protecting armor, and when below 

 the surface is absolutely secure against gunfire. But until 

 Hearing her naval quarry, the under-sea boat travels upon 

 the surface in what i- technically termed her "light" condition 

 In this state, having free access to the air. she is propelled by 

 means of explosive mot, rs nsmg either heavy oil or gasolene, 

 the newest types having recourse to the safer kerosene. Ex- 

 plosive engines use up air greedily and are therefore unserv- 

 iceable when the free atmosphere cannot be drawn on, but 

 they are able to drive the submarine at its highest speed along 

 the surface. 



for submerged travel the propulsive energy is electricity, 

 furnished by storage batteries, and this motive force must 

 he husbanded, for it has relatively a very limited capacity — 

 submarines living able to run at full speed, and that speed 

 considerably lower than the rate of surface travel, only for 

 about three hours. In order to prepare the boat for an under 

 water run her surface buoyancy is reduced by admitting tons 

 o water ballast into tanks built for the purpose. When at 

 last ready- for submerged work the remaining buoyancy as a 

 rule does not exceed 500 pounds. The boat is forcibly held 

 below the surface by- reason of her forward motion and the 

 pressure upon her submerging rudders, and should her en- 

 gines stop the 500 pounds of reserve buoyancy would cause 

 her to rise. But should leakage accumulate in the course of 



A Sister Shu- of the Famoi s German U-9 B - 



a run ever so slightly in excess of the original resi 

 buoyancy, then the craft would have a measure of "negative" 

 buoyancy and would certainly sink upon the stopping of her 

 electric motors. 



A gallon oi sea want weighs a little over eight pounds, 

 anil sixty gallons would be quite enough to wipe out that 



