Bowin 



lines throughout the ship were removed as far as possible or cut off 

 where further removal became impractical. New antenna lead-in 

 lines were then installed to avoid their approaching or intertwining 

 with the systems cabling as they had previously. Following this 

 action, which took place in the Fall of 1965, we have had practically 

 no radio frequency interference either from the ship's radio trans- 

 mitter or to the ship's radio receiver from the computer. 



Our second greatest source of difficulty has resulted from 

 operator action or misaction in performing his tasks. This will 

 be discussed in more detail later. 



The third most frequent source of trouble has been with 

 mechanical components of the system.] in particular the typewriters, 

 and to a lesser extent the reed-relays that operate the digital 

 display units. During the initial testing period the reed-relays 

 exhibited frequent failures which were difficult to analyze because 

 the trouble was intermittent and the displays were the means by 

 •which we were checking the values. However, once a good set of 

 reed-relay cards were found, they functioned very well from then 

 on. The typewriters broke springs, keys, and other parts which 

 in most cases were easy to replace. The system operation was 

 not seriously affected by these difficulties because by merely 

 throwing a switch the output could be transferred from one type- 

 writer to another. 



One of the sut"prising performances was given by the IBM 1311 

 disc drives. These disc drives rotate on a vertical axis at 1500 

 revolutions per minute. These rotating discs act as gyros, and it 

 was felt that during the rolling and pitching of the ship they would 

 exert considerable force upon the bearings in which they rotate and 

 thereby more rapidly wear those bearings. In four years of 

 operation we had only one bearing fail amongst the three disc drives, 

 and fortunately, although the spare bearing that we supposedly had 

 aboard the ship could not be located, a bearing amongst the ship's 

 spare parts did miraculously fit the unit and it was able to be 

 returned to operation. We did come, however, to the practice of 

 securing the disc drives during very rough weather. We still do 

 not know whether this is essential or not; our only experience 

 being that following a particularly rough storm, in which operation 

 of the discs was continued, oxide was noted around the outside of 

 the disc area and several scratches existed on the disc surfaces. 

 We do not know whether these scratches were formed during the 

 storm or were there before and only noted upon careful examina- 

 tion following the storm. However, this experience did cause us to 



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