SCIENCE AND THE SEA 



"■M 



^S" 



No case cited in this area. 



minutes later as the bow of Ship B penetrated 

 deeply into the port side of Ship A. 



ANALYSIS 



The primary causes of this collision were the 

 excessive speed at which both ships were navi- 

 gated during conditions of limited visibility and 

 the failure by the watch officer of each vessel 

 involved to reduce speed or stop upon detecting 

 another vessel ahead whose course and intention 

 were unknown. In each instance the responsible 

 officer was guilty of violating Rule 16. A con- 

 tributing factor which certainly should be cited 

 was Ship A's overreliance on faulty radar infor- 

 mation. 



As early as 12 minutes before the casualty, 

 Ship A's conning officer had detected Ship B and 

 recognized it as a large ship. One minute later 

 he further established that it was closing at high 

 speed and made the first of two substantial course 

 changes to the right in the effort to avoid a close 

 quarter situation. Had Ship B actually been in 

 the relative position reported, that is. dead ahead 

 when first detected, the evasive course changes 

 made by Ship A would pi'obably have had the 

 desired effect. Unfortunately, such was not the 

 case. A reconstruction of the courses steered by 

 the two ships during the final hour indicates that 

 Ship B's track was westward of Ship A's. At 

 0324, therefore, Sh ip B would have been about one 

 point on Ship A's starboard bow. Subsequent 

 events tend to support this contention. The obvious 

 misinterpretation of radar information by Ship A, 

 due probably to the large pip size on the 8-mile 

 scale and the now apparent miscalibration of the 

 radar set, led to the watch officer's decision to 



turn to the right directly into the path of Ship B. 

 Here is a perfect example of the fallacy of placing 

 too much reliance on radar data. 



Even five minutes before the casualty, Ship 

 A's watch officer had a further warning of the 

 impending danger when he noted that Ship B's 

 bearing had not changed appreciably. He failed 

 to heed this last warning and permitted the ship 

 to continue at top speed toward the approaching 

 vessel. 



Ship B's watch officer was, of course, bliss- 

 fully unaware of Ship A's existence until less than 

 five minutes before the tragedy. Here was a large 

 ship, being navigated almost solely by radar, pro- 

 ceeding through open water at high speed during 

 conditions of limited visibility, and the watch offi- 

 cer was employed, for the most part, in avoiding 

 local fishing craft. So occupied was he in doing so, 

 that rarely was his radar scope set to anything 

 but the 8-mile range, contrary to the tenets of 

 Rule 29, keeping a proper lookout. His turns to 

 the left, upon discovery of Ship A, were probably 

 correct tactics under the circumstances, but the 

 ship's high speed, unchanged until moments before 

 impact, placed it i» extremis before a truly 

 effective plan could be formulated. 



CASE 2 



The principals in this case were two dry-cargo 

 vessels which collided in heavy fog in the Pacific 

 Ocean approximately 10 miles westward of Cape 

 San Martin. California. The visibility at the time 

 of impact was variously reported as ranging from 

 zero to one-half mile. The wind was northwesterly, 

 force 4 to 5, sea conditions moderate with negli- 



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