The sinking Placed in Time

Jim,

There is also no reason why the ship would have been 20 miles ahead of her DR when those 7:30 sights were taken. You and I both know that. There certainly were no clock adjustment made between noon and when those star sights were taken at 7:30, so you can't blame the sights coming out 20 miles ahead of the DR on a clock setback. And that is the first thing that should have raised a red flag with Boxhall when he worked those sights out if his story about the ship being 20 miles ahead of the DR in 7 and 1/2 hours was true. The ship would have had to be going 2.7 knots faster than her assumed DR speed to achieve that, or easily over 24 knots. So what was Boxhall thinking if the 7:30 fix came showed the ship to be 20 miles ahead of the DR? Or was Boxhall being a good storyteller when he said that?

Pitman and Boxhall were the two guys who later claimed at the British inquiry that Smith turned the corner late. Pitman went so far as to say the turn was 50 minutes late. This of course is a bunch of nonsense since we know the ship had to be close to 126 miles from the corner at noon having ran 1549 miles by noon Sunday since taking departure off the Daunt’s Rock LV. The excuse of turning the corner late was made up to explain how the ship arrived at Boxhall’s CQD position at the time that it did.

I think you can tell that I don’t think too highly of either Boxhall or Pitman when it comes to relying on what they said.

So back to basics. No matter what you want to assume or believe, you cannot simply ignore that most passengers and crew alike put the accident time near 11:40 pm, and the foundering time near 2:20 am. This would not have been the case if the wheelhouse clock controlling the watchkeeping schedule of the deck and engine dept crew was put back before the accident happened. There was NO dichotomy in the times reported.
 
Your are avoiding the obvious Sam! People working on ships don't get out of bed 44 minutes before going to work!
20 miles back from Smith's CQD put him on top of the wreck!
29 minutes back from Boxhall's CQD puts him back on top of the wreck as well! Remember he allowed 5 or 6 minutes on from impact!

As for your remarks about Pitman - most unfair and unwarranted.
First of all he did what every other practical navigator would do - round up or down small fractions. He did not have a calculator - just 4 figure logarithms.
However he worked the total Great Circle distance exactly - 1618. Incidentally I make the initial course to be 241.5T and the final one 236T. If I'm right, and Lowe's 14th Noon alteration was right then Titanic was quite a bit south of where she wanted to be at that time.

Pitman worked the Great Circle as normal. It was a very shallow course - only 5 degrees difference between start and finish. From his memo, you can see that he split the circle 326 -1000-96. he also pre-calculated the clock change - hence the 44 minutes on two 11 degree legs (normally, slow ships use 10 degree legs (easy to check with the traverse table). I don't know why you refer to Dublin time - all navigators worked exclusively in GMT. As for the funny 20.14 knot speed... I'll use your excuse: it was probably a typo error.. 484 divided by 22.6 is 21.4 (rounded up) . But just in case: The average speed of 20.14 is highly probable - particularly at the beginning of the voyage since Titanic was well within the influence of the horrendous tidal streams off the coast of Ireland. The tides the that area of the southern approaches to the Irish Sea are particularly fierce. An initial speed of 18 knots on a ship expected to do 20 between Daunt's Rock and Fastnet would not be out of the question.
 
Sorry, the total Great Circle distance is 1560. 1618 is the total distance Daunt's Rock to The Corner. The 58 miles is the total run from the anchorage.
 
A hellish thing old age! I was right the first time. The Great Circle distance was indeed 1618.
The initial course was 264.5T and the final one was 236.5T - I looked up the nat.hav.of the first instead of the log hav. I reserve the right to be 'sloppy' at my age!

Calculated Total distance from weighing anchor at 1330 on 11th.April to The corner is 67+1618 = 1675 miles. Total distance to Noon on the 14th according to Pitman was 1549 miles. The difference between these two is 126 miles - exactly what Lowe said! Not too sloppy!

When calculating the average speed for the first day's run, it should be remembered that Titanic would proceed very slowly from the anchorage at Queenstown to disembark the harbour pilot off Gaunt's Rock L/V. She would be making no more than a few knots while the pilot was disembarked. Smith would not ring down f.a.o.p (full away on passage)until Titanic started to pick up speed after the pilot had left. At that moment, Titanic would almost be stopped. This, as well as the possible effects of the tide must be taken into consideration when discussing the first partial day's run. If Titanic made 21 knots on day 2, it is highly likely she made a good bit less than that on the first day. One this is certain- she would not be making 21 knots when she passed Daunt Rock Lightvessel.
In any case, According to Ismay, they started the voyage at 68 rpm... about 20 knots? How long did they run at that for? Until Noon on the 12th?
Whatever! - it is highly unlikely that Titanic averaged any more than what Pitman suggested (20.14 knots) during that first leg of the voyage. The conditions did not exist for her to do so.

As for Pitman's little bit of arithmetic at the end? Well he was not a statistician - just a simple sailor. He did what most of us did; took the average speed for each day added these values and divided the sum by the number of days to get what was termed 'General Average Speed'. Not the least bit sophisticated but ample for what was required. His answer should have been 21.51 knots. He used days rather than hours. No big deal! Strictly speaking, he was arithmetically correct in that the three values he used added together and divided by three did give an 'average speed'.
 
>>Sorry, the total Great Circle distance is 1560. 1618 is the total distance Daunt's Rock to The Corner.<<

No, 1618 is the total great circle distance from Fastnet to the corner steering the great circle. The distance run from Daunt's Rock to Fastnet is about 55 miles, and is also the distance listed for that run in James Bisset's nautical notes for ocean travellers book "Ship Ahoy!!".

>>As for your remarks about Pitman - most unfair and unwarranted. <<

I don't think so.

If you add up those markings in Pitman's memo for days 1 and 2, you get 326+1000+96+250+3=1675 miles. That is the total distance from Daunt's Rock to the corner. Now 1675-55=1620 miles is the great circle distance from Fastnet to the corner following straight line segments that the ship would travel. The sum total of the actual runs for the first three days to noon Apr 14 as listed is 484+519+546=1549 miles. Difference from 1675 total miles from Daunt's Rock to corner is 1675-1549 = 126 miles, the distance from noon Apr 14 to the corner.

In calculating his run times, Pitman had 24 hrs 58 min from noon Thu to noon Fri. But the ship was off Daunt's Rock at 2:20 pm. That's why he subtracted 2:20 from 24:58 to get 22 ht 38 min as the run time to noon Fri. But this also shows that he allowed only 58 minutes to get from what GMT to apparent time for the first day out? That's a change of 14° 30' of arc. But the longitude for noon Fri, using the 484 miles distance from Daunt's Rock, would be near 20° 43'W, not 14° 30' W. However, if that departure time was in local mean time for Queenstown, which was 25 minutes behind GMT, then we get a difference of 83 minutes from GMT at noon Fri, or 20° 45' W longitude, which is close to the position that I get for ship's position at local apparent noon (LAN) Fri. That's why I suggested he put down Dublin Mean Time for the 2:20 pm departure off the light vessel. (The abstract log would have listed the departure time off Daunt's Rock in GMT.)

Now for noon Fri to noon Sat, and from noon Sat to noon Sun, Pitman moves the ship 11° in longitude each day as far as time is concerned. But that does not correspond to the distances the ship traveled each of those days. LAN Sat the ship was near 33° 10' W, and LAN Sun the ship was near 41° 31' W to match the individual distances run between LAN one day to LAN the next day. The changes in longitudes are 12° 27' and 11° 21' respectively. At noon Sun, apparent time was 2 hrs 58 min behind GMT. If you add up the changes Pitman used we have 58 + 44 + 44 =146 min = 2 hr 26 min from GMT if he started from GMT; or 146 + 25 = 171 min = 2 hrs 51 min from GMT if his starting time was in DMT. Either way, it does not match the longitude of the ship for LAN Apr 14. His time runs, two of which are based on 11° longitude changes, throws his calculated speeds for each day in error.

And as I mentioned, the way he calculated a mean hourly speed was not the way you do that.
 
It seems you posted moments before I did. Anyway, I'm happy to see that we agree on the 126 miles distance to the corner at noon Apr 14.

The 2:20 time in Pitman's memo was the time departure was taken off the Daunt's Rock lightship, not when she lifted anchor or dropped the pilot. It was the starting point for all atlantic crossings leaving Queenstown.

As far as calculating mean voyage speeds, the J/Os always did that. Looking at one of Olympic's log cards we see that the mean voyage speed was always calculated by taking the total distance travelled from Daunt's Rock LV to Ambrose LV and dividing that by the total time run between those two points. It's something I would have expected Pitman to know to do.

According to Ismay, the ship started out from Queenstown at 70 rpm. On Friday sometime, she was doing 72 according to his recollection. By Sat noon she was doing 75 rpm.

Cheers,
 
Yes Sam I know that Pitman used the 2-20 time. But he would be referring to when the ship was off Daunt Rock L/V. As I said I my last post, the ship would be almost at a standstill until the pilot was dropped-off. If you take the full distance of the great circle course- 1618 and add the run between Daunt Rock and Fastnet - 55, you get a total of 1673 miles . But Pitman's total for the three daily runs is 1675 (adding the 126 miles from Noon on the 14th. From this it seems he accounted for the three miles from the anchorage to Daunt Rock.
Perhaps you already know, but the method of 'smoothing out' a great circle course was to calculate a course change every 10 degrees of longitude. This is what Pitman or someone would normally do. It therefore meant that the junior would need to have a very good idea of speed and be able to advise the master when it was time to alter onto the next leg of the voyage. If we calculate in this way for the first 10 degree leg from Fastnet on 246.5T, we get a total distance of 468 miles and a run time of 21.81 hours. This would make the first 'way point' to be 50-32.2'N..19-36'W. This would be at about 1428 hrs ship. If we run that back 53 miles to Noon, we get a Noon position of 50-36.8N..18-12'W and a total distance run from Daunt Rock of 518 miles. Pitman shows a run of 519 miles... strange?
 
>>Yes Sam I know that Pitman used the 2-20 time. But he would be referring to when the ship was off Daunt Rock L/V. As I said I my last post, the ship would be almost at a standstill until the pilot was dropped-off. <<

The Atlantic crossing between Queenstown and NY was recorded from departure off Daunt's Rock LV to arrival off Ambrose LV. The crossing time was measured in days, hours and minutes from departure to arrival off those lightships. Yes a pilot would be dropped off before reaching Daunt's Rock and a pilot would picked up after reaching Ambrose. But the start time for the crossing was recorded after the pilot was dropped off and the ship put on a course for a point south of the Old Head of Kinsale and the Daunt's Rock LV abeam. The ship would already be picking up speed.

The end of the voyage would be marked when the Ambrose LV was abeam, before picking up a pilot to take the ship up the narrows to quarantine off Staten Island in upper NY bay. I know those waters quite well.

>>But Pitman's total for the three daily runs is 1675 (adding the 126 miles from Noon on the 14th.<<

Now you know that actual distance travelled along the GC would have to be somewhat greater than the actual GC distance because the ship would be taking several rhumb line segments along the route. Pitman did not add 2 miles for anchorage distance to the LV. The distance from Queenstown harbour to the LV was 7.5 miles.

>>Pitman shows a run of 519 miles... strange?<<
The run of 519 miles is from noon Fri to noon Sat. The first day's run was 484 miles.

Face it. The run times listed in Pitman's memo were all wrong, and so too were his speeds.
 
Yes Monica, drive around downtown Chicago amongst those tall buildings and the GPS display in your vehicle can at times show you to be a block or two away from where you really are, off the street, and even pointing you in the wrong direction. These devices are only as good as the signals they receive.
 
Sam, I did that particular run on many an occassion.(and ran the numbers) I am in the process of re-running Pitman's numbers in reverse (if I can remember how) and will let you have my results if you're interested.

Hi Monica!

Great thing GPS (at sea that is). Most times when in the car, I already know where the supermarket is so don't need one but they are amazing little fun things!

Jim
 
>>Well, I would say thank goodness for Sat Nav and computers ... except someone is simply bound to tell me that they get it wrong too.<<

And they would be right. However, the nice thing about GPS is that it's off by a much smaller margin.
 
And what time did the Carpathia arrive?

Or even better - is there a timeline anywhere that gives the specific times of events such as these?

Many thanks.

[Moderator's note: This post, originally posted in a separate thread has been moved to here, which is discussing the same subject. JDT]
 
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