92 



discovi:hv 



Before long, no doubt, the wireless telephone will come 

 into more extensive use for maritime communications, 

 but for some time to come it is likely to remain as much 

 a luxury for ships as the telegraph is for aircraft. The 

 great ad%-antagc of the telegraph over the telephone is 

 that much longer ranges can be obtained for the same 

 expenditure of electrical energy, and the great dis- 

 advantage is that a telegraphist is required to work 

 the apparatus, though it must be remembered that 

 even the operation of a wireless telephone requires a 

 certain amount of training. There is an obvious 

 future for telephony in ships when arrangements can 

 be made for communication through land stations 

 direct with subscribers on the telephone system of 

 the country; but we had better confine ourselves to 

 the present time, when, as a matter of fact, such 

 arrangements are not in operation, and wireless 

 telephony is not used for ship and shore communica- 

 tions. On the other hand, wireless telegraphy is now 

 universally recognised ais an essential fitting for the 

 safetj' of life at sea, and in this country has recently 

 been made compulsory for all sea-going ships which 

 are passenger steamers, or ships of i,6oo tons gross 

 tonnage or upwards. This includes over 3,000 

 British ships. In vessels carrying 200 or more persons, 

 three operators are normally carried, and a continuous 

 watch is kept. In those with 50 to 200 persons, 

 continuous watch is also kept, one operator and at 

 least two " watchers " being carried ; and in the 

 remaining ships watch is kept for eight hours daily 

 at specified times, one operator only being carried. 

 The qualifications required in the case of a watcher 

 are such as to ensure his recognising the general 

 distress call and the safety signal. Should he hear 

 either of these calls, he turns over the watch to a 

 skilled operator. Any person in the ship, if so qualified, 

 may act as a watcher. 



In this country the Post Office issues licences to 

 ships in respect of their installations, and certificates 

 to operators and watchers who qualify at examinations 

 conducted by that Department. The land stations for 

 communication with ships (see map) are all worked by 

 the Post Office, with the exception of the station at 

 Poldhu, which is used partly for broadcasting Press and 

 other messages to ships, that is, sending out messages 

 without receiving replies. This station is worked by 

 the Marconi Company. The station at Devizes is fitted 

 with continuous wave apparatus, and communicates 

 up to distances of about 1,000 miles, on a special 

 wave-length of 2,100 metres, with such of the large 

 liners as are similarly fitted in addition to their com- 

 pulsorily-fitted installations. The other stations use 

 spark apparatus similar to that compulsorily fitted in 

 ships, and keep watch on the 600 metres wa\'e, which 

 is that used for distress messages and, in fact, for 



practically all messages sent by ships, with the exception 

 of the long-distance traffic mentioned above. The 

 compulsorily-fitted installation must be capable of 

 communicating with a standard Post Office station up 

 to at least 150 miles, but communication up to 200 or 

 300 miles is usually obtained according to the power 

 of the installation fitted. 



As a general rule, ships keep watch with their receiv- 

 ing apparatus adjusted for the reception of the 600 

 metres wave, and are thus ready to receive any 

 message of distress from a ship within range or a call 

 from a ship or land station. The wave-length of 

 600 metres was detailed for this purpose in the 1912 

 Convention, as it is a very suitable wave for trans- 

 mission from ships of average size, and it was very 

 necessary to lay down some one definite wave on 

 which distress messages would be sent, and would 

 have as good a chance as possible of being received 

 by all ships and land stations within range. A 

 distress message is preceded by a signal consisting of 

 three dots, three dashes, and three dots sent as one 

 sign, and repeated at short intervals. This is usually 

 alluded to as the S.O.S. signal, though the letters 

 S.O.S. sent as a group in the Morse Code is not really 

 the same as the distress signal which is sent as one 

 sign. When this signal is received all communication 

 ceases, except that consequent upon the call for help. 

 The safety signal consists of three dashes repeated ten 

 times at short intervals, and is sent as a preliminary 

 to information of an urgent character involving the 

 safety of navigation, e.g. icebergs, derelicts, cyclones, 

 etc. The idea of adopting some such warning signal 

 resulted from the inquiry into the loss of the liner 

 Titanic, which struck an iceberg and sank on April 15, 

 1912. In this case the S.O.S. signal was responsible 

 for saving over 700 lives, and if a safety signal had 

 been in general use, it is quite likely that the whole 

 terrible disaster would never have occurred. 



It is hoped that before long satisfactory automatic 

 apparatus for registering the distress signal wdl be 

 deNased, in which case it is laid down that British 

 ships, now only compelled to carry one operator, 

 shall also be fitted with this apparatus, and ships which 

 carry watchers as well as an operator may substitute 

 the apparatus for the watchers. 



The international regulations framed at the 1912 

 Convention for maritime wireless signalling are still in 

 force, but are in much need of the revision which 

 normally would have taken place three years ago, 

 and which it is hoped may be arranged for this year, 

 as the great strides made in wireless practice during 

 the war have naturally overstepped the somewhat 

 restricted boundaries of the Convention. 



As a matter of fact, the apparatus used in merchant 

 ships was much the same at the end of the war as at 



