Ok Jim, I’m gonna give you my trick but don’t tell nobody. I was standing in the corner of the bridge by the very first window; remembering that I was docking the beast. I was then protected from the door wind draft in the same manner as the crow’s nest canvas windshield. As I am an expert with flies as being a sport fisherman, I lit up and pumped out vigorously a big stinky Malboro cigarette. But I must admit that there was a few on my PPU screen, keyboard and in my coffee cup. But they just add taste to that infect instant Nestlé coffee they serve.
Jim, if you divide the distance by the time between two celestial fixes, it gives the speed over the ground. It was a concept widely used at the time. They were probably using both method and compare them to find out if they had applied the proper current effect on the log. For daily average and general speed log inscriptions, they were using speed over the ground. If they couldn’t take any sights for days, they probably had to figure out a calculated speed over the ground derived from a current corrected speed in the water, compare to the average rpm/pitch/slip and or from previous voyages. If not, there would land up with large differences in day to day speeds which could have to be justified. Even in that era, I guess they were trying everything possible to keep away the office nose from the ship’s business.
Jim, if you divide the distance by the time between two celestial fixes, it gives the speed over the ground. It was a concept widely used at the time. They were probably using both method and compare them to find out if they had applied the proper current effect on the log. For daily average and general speed log inscriptions, they were using speed over the ground. If they couldn’t take any sights for days, they probably had to figure out a calculated speed over the ground derived from a current corrected speed in the water, compare to the average rpm/pitch/slip and or from previous voyages. If not, there would land up with large differences in day to day speeds which could have to be justified. Even in that era, I guess they were trying everything possible to keep away the office nose from the ship’s business.