1905.] on Submarine Navigation. 163 



Concurrently with the construction of submarines, experiments 

 have been made in this country and abroad to discover the best means 

 of defence against this method of attack. Here again authentic details 

 are necessarily wanting, since the various naval authorities naturally 

 wish to keep discoveries to themselves. It is very probable, however, 

 that published accounts of tests between swift destroyers, vedette 

 boats and submarines are not altogether inaccurate, and according to 

 these accounts the periscopes of submarines have been found useful 

 by assailants as the means of determining the position of the 

 submarines, and aiding their entanglement. Comparatively limited 

 structural damage to a submarine in the diving condition may be 

 accompanied by an inflow of water in a short period, which wall result 

 in the loss of the vessel. The accident to Submarine A 1, which was 

 struck by a passing mail steamer, illustrates this danger. It is reason- 

 able to accept the published reports that large charges of high ex- 

 plosives exploded at a moderate distance may have a serious effect 

 against submarines, and cause them to founder. Their small reserve 

 of buoyancy in the diving condition makes them specially liable to 

 risks of foundering rapidly, and little more than a crevice may prac- 

 tically fill the interior with water in a very short time when the vessel 

 is submerged even to a moderate depth. On the other hand, reports 

 which have appeared of the manoeuvres in France and elsewhere, 

 when attacks have been made by submarines on vessels at anchor or 

 under way, show a considerable percentage of successes. Such 

 exercises are valuable no doubt for purposes of training, but under 

 peace conditions it is necessary to avoid the risks of damage to 

 submarines, which might easily become serious if the defence were 

 pressed home as it would be in war. When the officers and crews of 

 submarines know that they will be treated more considerately than in 

 real warfare, they will naturally take chances, and make attacks in- 

 volving possible destruction under the conditions of a real action. 

 In short, naval manoeuvres in this department, while they may be 

 useful in increasing the skill and confidence of officers and men in 

 the management of submarines, can be no real test of fighting 

 efficiency. 



Submarines and airships have certain points of resemblance, and 

 proposals have been made repeatedly to associate the two types, or to 

 use airships as a means of protection from submarine attacks. One 

 French inventor seriously suggested that a captive balloon attached 

 to a submarine should be the post of observation from w^hich informa- 

 tion should be telephoned to the submarine as to the position of an 

 enemy. He evidently had Uttle trust in periscopes, and overlooked 

 the dangers to which the observers in the car of the balloon would 

 be exposed from an enemy's gun-fire. Quite recently a proposal has 

 been made by M. Santos Dumont to use airships as a defence against 

 submarines ; his idea being that a dirigible airship of large dimensions 

 and moving at a considerable height above the surface of the sea, 

 could discover the whereabouts of a submarine, even at some depth 



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