A New System for Preventing Collisions at Sea 



as the echo ; 45 minutes later we send out a blast and receive 

 a faint echo which tells us that the ship is ten miles distant. 

 A few minutes later the echo is very strong, makes a decided 

 record, and rings our smallest bell. We make other records 

 as the ship approaches, and when she is off our port beam, 

 broadside on and only half a mile distant, she sends us a 

 blast that we can feel if not hear. It rings all our bells 

 violently, and causes every light object on the deck to vibrate. 



The following day we only exchange messages with other 

 ships ; night comes on, we encounter a dense fog and by mid- 

 night are on the Banks of Newfoundland. We are constantly 

 sending out blasts without receiving any response. However, at 

 about two o'clock in the morning, we do receive a response ; it is 

 only slight and only a short distance away, so we know it is 

 some small object, which we soon pass without seeing it, Later 

 on we receive a series of records from each blast, showing that 

 there are several small objects in our vicinity, probably fishing 

 boats. We are able to locate them and measure their distance, 

 and if any of them are dead ahead of us, we change our direction 

 so as to give them a wide berth. When daylight appears, we 

 are still in a dense fog ; we make out and communicate with 

 several ships that have our apparatus, but we fail to see any of 

 them. About nine o'clock in the morning we have a new ex- 

 perience ; we send out a blast and receive back an echo showing 

 that there is an exceptionally large object very nearly dead 

 ahead of us. We know it is large because the distance indicated 

 is ten miles and the record quite distinct. By sending out 

 repeated blasts, we find that the distance between us and the 

 object diminishes about one-third of a mile in a minute. This, 

 of course, is due to our own speed, and indicates that the object 



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