NavList:

   

Reply

Some time ago Geoffrey Kolbe described his method of taking four stars
so as to be able to eliminate constant errors. Take one north, one
south, one east and one west, ( or take pairs as close to being on
opposite azimuths as possible.) Pairs taken this way will reveal any
constant error in the observation and it seems like a good idea to me.
While traveling last month I stopped in Denver and visited the house
of "The unsinkable Molly Brown" a survivor or the Titanic. We have all
heard the story of that accident but these are all second hand. I
found on sale in the gift shop a book containing the sworn testimony
of the survivors and it makes fascinating reading. I also found a web
site where the testimony is available:

http://www.titanicinquiry.org/

Reading through the testimony of Fourth Officer Boxhall I found that
he had used this exact technique to determine the Titanic's position
on the night of the iceberg collision. I have attached this part of
his testimony, it makes exciting reading.


gl


Senator BURTON.
The captain of the Mount Temple maintains that the course as conveyed
by the distress signal was wrong; that the Titanic was actually eight
miles distant from the place indicated. What do you say as to that?

Mr. BOXHALL.
I do not know what to say. I know our position, because I worked the
position out, and I know that it is correct. One of the first things
that Capt. Rostron said after I met him was "What a splendid position
that was you gave us."

Senator BURTON.
You gave them what position?

Mr. BOXHALL.
41� 46', and 50� 14'.

Senator BURTON.
And you are satisfied that was correct?

Mr. BOXHALL.
Perfectly.

Senator BURTON.
You computed it yourself, did you?

Mr. BOXHALL.
I computed it myself, and computed it by star observations that had
been taken by Mr. Lightoller that same evening; and they were
beautiful observations.

Senator BURTON.
Who made the computations on them?

Mr. BOXHALL.
I did. You asked me if the officer who took the observations and the
one who made the computations compared their results?

Senator BURTON.
Yes.

Mr. BOXHALL.
I do not see what there is to compare. The officer who takes the
observations always is the senior officer.

Senator BURTON.
He writes those down, does he?

Mr. BOXHALL.
He simply takes the observations with his sextant. The junior officer
takes the time with the chronometer, and then is told to work them
out.

Senator BURTON.
That is, another person works them out?

Mr. BOXHALL.
Yes. If he does not think these things are correct, he tells you to
work them over, and you have to do it.

Senator BURTON.
Would there not be some danger of your mistaking a figure, or
something of that kind, that is written down by another person?

Mr. BOXHALL.
When you take stars you always endeavor, as they did that night, to
take a set of stars. One position checks another. You take two stars
for latitude, and two for longitude, one star north and one star
south, one star east and one star west. If you find a big difference
between eastern and western stars, you know there is a mistake
somewhere. If there is a difference between these two latitude stars
you know there is a mistake somewhere. But, as it happened, I think I
worked out three stars for latitude and I think I worked out three
stars for longitude.

Senator BURTON.
And they all agreed?

Mr. BOXHALL.
They all agreed.

Senator BURTON.
What time did you do that?

Mr. BOXHALL.
I really do not know what time it was. I was working these things out
after 8 o'clock, and Mr. Lightoller took them before 8 o'clock.

Senator BURTON.
About how long was that before the collision?

Mr. BOXHALL.
The collision was at 11.43, I think.

Senator BURTON.
And how long before the collision did you make this computation?

Mr. BOXHALL.
I suppose about 10 o'clock. Yes; I finished before 10 o'clock, because
I gave Mr. Lightoller the results when I finished.

Senator BURTON.
And the result as to the position of the ship was arrived at by
computing your speed after 10 clock to the time of the collision?

Mr. BOXHALL.
Yes.

Senator BURTON.
You are very sure it was right, and Capt. Rostron said it was?

Mr. BOXHALL.
Capt. Rostron said it was a very, very good position. After I had
worked these observations of Mr. Lightoller's I was taking star
bearings for compass error for myself, and was working those out. That
is what kept me in the chart room most of the time. I was making
computations most of the time.

Senator BURTON.
Did you yourself receive these messages relating to ice?

Mr. BOXHALL.
I received those I copied.
--~--~---------~--~----~------------~-------~--~----~
Navigation List archive: www.fer3.com/arc
To post, email NavList@fer3.com
To , email NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---

   

Reply