116 SUBMARINE SIGNALING AND A PROPOSED 



Danger of collision in fogs has greatly increased in recent years on account of 

 the great increase in both the size and speed of vessels. 



The inexorable law of energy being proportional to the product of the mass 

 multiplied by the square of the velocity unfortunately applies equally to ships and 

 to projectiles, and the energy of the 55,000 tons of the Titanic at a speed of 21 

 knots equalled the striking energy of forty 12-inch shells. 



The sole means of avoiding collision in a fog at the present time is that pre- 

 scribed by the "Rules of the Road," viz., the fog whistle or siren. So far as 

 range, efficiency and reliability are concerned, the fog signals of the Olympic, 

 Imperator or Wyoming have made no appreciable advance since our largest men- 

 of-war used steam as auxiliary to sail power. Fog navigation is still in the dark ages, 

 and in this field science has found itself literally "befogged." 



A system of handling vessels in a fog, which for want of anything better 

 may be said to have worked fairly well with sailing vessels and low-powered 

 steamers of small size and low speed, has under present-day conditions broken 

 down. 



The rules of the road have evaded a definite law prescribing and defining the 

 term "moderate speed." This definition has been left to admiralty courts to in- 

 terpret, but always after the collision. 



An examination of some of the decisions is illuminating. H. Stuart Moore in 

 the "Rules of the Road at Sea" cites numerous decisions as, for example, in the 

 English Channel 3^^ to 4 miles per hour was held to be immoderate, and 200 miles 

 east of Sandy Hook the courts have held that 7 knots exceeded the speed limit. 



In January, 1914, the Navy Department by general order called the atten- 

 tion of the Naval Service to the subject of speed in a fog, referring to the text-book 

 on seamanship by Admiral Knight. In discussing the handling of a ship in fog this 

 text-book states: — "An officer hearing the fog signal of a vessel which he cannot 

 see can usually form a general idea of its bearing and may be able to judge some- 

 thing of its distance, but even with regard to these points there is danger of serious 

 error, and of all other points he is absolutely ignorant. * * * ^ steamer's whistle 

 can be heard, under favorable circumstances, two miles or more, * * * i^^^- 

 so many things affect the question of audibility that it is not safe to rely upon 

 hearing it more than, say, half a mile, even when all conditions seem to be 

 favorable." 



The standard turning circle used in our fleet is half a mile in diameter. 



The classic investigations of Tyndall in sound demonstrated that air is unre- 

 liable and, indeed, frequently erratic as a sound conveyer. Refraction and other 

 causes often produce zones of silence near the source of sound. In the course of 

 his investigations for the British Government in 1874, conducted near Dover in 

 the English Channel, he found that the intensities of fog whistles, sirens and gun- 

 fire were fifty times greater in some conditions as in other instances observed, and 

 the poorest results were obtained when conditions were apparently favorable. 

 These conclusions are confirmed by the experience of seagoing men; where some- 



