I was always under the impression that a ship's position is only as good as it's last fix? All the discussion of the timing and location of the turn to the final course seems a bit 'smoke and mirrors' to me.
What I find strange is that 2 highly experienced navigators couldn't work out the ships position after 4 hours (give or take) in a straight line from a known good fix. Conditions that night were pretty much perfect for taking fixes and for keeping on track. Clear skies, flat seas and light airs. The QM could hold the ship on course with the tips of his fingers.
Boxhall worked up the fix taken at around 19:30. All he needed to know was the speed of his ship and the course to know where they were at 23:40.
That's 4 hours and 10 minutes at, between 21 and 22 knots.
Captain Smith's position was about 20% too far and Boxhall's about 10%. Ships don't end up 20 and 13 miles from a known good fix in 4 hours unless someone screwed the maths.
Rob, you are right! Two such men could perform such simple tasks standing on their heads. A Second Year Cadet or Midi could do the same thing. We are not considering professional incompetence.
Captain Smith used false information provided by A. N. Other. Boxhall obviously mis-judged the speed and
used the wrong run-time.
By your "Smoke and Mirrors" observation are you suggesting "the obscuring or embellishing of the truth of a situation with misleading or irrelevant information."?
Nothing could be farther from the truth.
In fact, Titanic's
behavior between Noon, April 14 and 5-50 pm that early evening, is the
lynch-pin of the clock alteration argument as well as the basis on which Boxhall built his distress position. Simply because it determines exactly where Titanic
was when 2nd Officer Lightoller took his star sights and consequently established the exact position from which Boxhall worked his distress position. If that period in the short life of Titanic is glossed-over without proper examination, then we go on having this endless argument.
Aaron's current suggestion is a start.
Here is another question. Q7:
Was there any evidence to suggest that such a current existed? Might it be reasonable for an experienced officer to expect such a current and allow for it? A7
: Yes! The evidence of 5th Officer Lowe very clearly indicates a reduction in expected speed, which, if using propeller revolutions would be judged as 21.5 knots. Lowe very clearly quoted an average speed of 20.95 knots...0.55 knots slower than expected.