Thanks for that Sam. Some very strange goings-on on these two ships! Course line going of the edge of the course recorder chart... really?
That year of 1956, was the year that I completed the UK B.o.T Radar Observer's Course at Leith breakwater and a Sperry Gyroscope course at what is now Strathclyde University. Your remarks:
"According to Captain Raoul De Beaudean of the
rescue ship Ile de France, radar readings on scopes in the1950’s had an uncertainty of about 4 to
5 degrees. This can explain some of the reporting error in Stockhlom’s radar bearings,
especially when coupled with the fact that the third officer depended on his helmsman to give
him his ship’s precise course heading, a helmsman who was not very reliable in keeping to a
steady course.
Did not sit well with some practical memories of those far-off days.
First, I do not agree with the French captains' remarks. I certainly never found any such problem with our Sperry, Kelvin Hughs, Decca or Marconi equipment and I used it very often as a check using actually sighting targets during coastal navigation. Did the same thing with our Decca Navigators.
As for good and bad steering... this would not be an issue. In reality, when taking a bearing with the then radar equipment, the officer would activate the curser and the variable range marker. He would then engage the target. This went on a great deal when coasting and navigating in busy waterways. The helmsman would be anticipating the next move and would already be steadying her head on the course. Then the officer would give the order "let me know when she is right-on quartermaster". When the QM reported "right-on now sir", a bearing and range of the target would be taken. This might be done more than once. In fact use of RDF stations was more of a hit and a miss in those days. I know for a fact that the Nantucket Light ship had a very well defined radar signature. It was usually the only target that wasn't moving. I wonder if Stockolm ever saw it on her radar?
As I see it the universal instruction: if the bearing of another vessel [obtained by whatever means]does not appreciably change then the danger of collision must be deemed to exist".was completely ignored by both captains in this sad saga.
Jim C.