48 



were obtained by the use of the after oscillator than by the use of the 

 forward apparatus. 



(/) That the present equipment is a valuable means of conven- 

 iently determining depths and thereby a valuable aid to navigation. 



(r/) That the apparatus in its present development is not a suitable 

 means for detecting icebergs and would not be sufficient to avert 

 a collision, due to lack of echoes from dead ahead and the limited 

 ranges. 



(h) That specially trained operators are required for this particular 

 work, necessitating additional members in the complement of the 

 vessel for constant watch. A personal error was noted in practically 

 all observers. It has been observed that the greatest personal error 

 in operation was in depths of between 15 and 60 fathoms, and where 

 the bottom was sloping or irregular. Ensign Richards was the most 

 efficient observer, especially in shallow water, both with the angle 

 method and sonic depth finder. 



(?') That the scope of the present apparatus is very limited and the 

 apparatus too unwieldly for constant use to be of value as an obstruc- 

 tion detector. It is uncertain in its results to the extent that detec- 

 tion at this stage is really a matter of chance with the odds decidedly 

 against the vessel. The sound wave, spreading in all directions 

 caused echoes from a number of points at times. 



(j) The compensator bearings were not reliable. If the general 

 bearing of the object were known it would be possible to obtain fair 

 results — the accuracy of the bearing being dependent, as above shown, 

 on the depth of the water, the intensity of the echo and the speed of 

 the vessel. 



(k) That the present location of the forward oscillator afforded a 

 very poor installation, due to direct sound. 



(I) That the location of the after oscillator was not very favorable 

 for echoes from ahead. 



(?n) That an iceberg forms a medium for reflecting submarine 

 sounds. 



(n) That an echo was invariably received from a berg on all ap- 

 proaches under normal conditions. That the side of approacli, 

 whether to windward or leeward, had no material effect on the in- 

 tensity of the signal. 



(o) That no direct echoes from liergs were received in so far as the 

 operating personnel could identify. All echoes were recognized as 

 reflected echoes from the bottom. 



(p) That local noises, while very noticeable, did not seem to affect 

 the reception to a marked degree while at anchor or when hove to, 

 but while under way under abnonnal sea conditions in deep water, 

 the interference was very marked. 



