Carpathia's position and calculated course to rescue survivors


Jon EH

Member
Jul 24, 2019
5
0
1
The Netherlands
I've read quite a lot on the position of the Titanic as given in various CQD messages. But I am interested in trying to reconstruct the path of the Carpathia.

Does anyone know if there is a copy of her log book on line?

The particular items of interest to me are:

1) Prior to the receipt of the CQD, what was the last logged position of the Carpathia as measured by instruments as opposed to calculated from that position based on speed.
2) What coordinates did Captain Rostron calculate for the Carpathia's position after Harold Cottam made him aware of the CQD. (In his testimony, TIP | British Wreck Commissioner's Inquiry | Day 28 | Testimony of Arthur H. Rostron (Master, SS Carpathia), he gives the course and position as "N. 52 deg. W., 58 miles", which allows the reverse engineering of this starting point as being about 41 deg 15 min North, 51 deg 7 min West, but I'd like to know if there is any record of this, was it written in the log? can I find documentary evidence on line?)
3) Any details of the calculation Captain Rostron made to derive 2 above from 1 above (i.e. Was he assuming an average speed? What course settings did he use).
4) Did anyone on the Carpathia confirm their position with instrumentation after the initial calculation was made?
5) Did the Carpathia change course from N. 52 deg based on instrumentation, or for any other reason than avoiding ice up to the point he saw the first flare? (Captain Roston's testimony (link above) says: "At 20 minutes to 3 I saw the green flare ", and later on the same page "it was just about half a point on the port bow").
 

AlexP

Member
May 23, 2019
355
16
18
Usa
which allows the reverse engineering of this starting point as being about 41 deg 15 min North, 51 deg 7 min West,
In another thread Jim calculated them to be 41-14.2'N, 49-04.7'W

The path of the Carpathia had been reconstructed, but because on her path she was missing lifeboats for more than 6 miles her path was changed
 

AlexP

Member
May 23, 2019
355
16
18
Usa
As far as I'm aware, the information you seek does not exist. Also, you said, "the reverse engineering of this starting point as being about 41 deg 15 min North, 51 deg 7 min West." That is clearly incorrect.
Samuel, maybe you know on what latitude the Carpathia was at around 10 p.m. April 14?
And maybe you know at what altitude was the Polaris at 3 a.m.?
Thanks.
 

Jon EH

Member
Jul 24, 2019
5
0
1
The Netherlands
As far as I'm aware, the information you seek does not exist. Also, you said, "the reverse engineering of this starting point as being about 41 deg 15 min North, 51 deg 7 min West." That is clearly incorrect.
Thanks for the reply.

I have seen "Brian J. Ticehurst" quoting from the log book of the Carpathia, on this thread: Trimmer

Brain said: "The Official Carpathia Log Book No. 6. / No. 1 Board of Trade number 100/156 8437 consisting of 46 pages for 377 men covers the period from when the Carpathia set off from Liverpool on 10th February 1912 until she returned to Liverpool on 1st January 1913."

So presumably it still exists, and if so would it not have at least the answer to my first question? They would have to write down each time they used instruments to calculate their position right?

On the "reverse engineering", it would be easy to convince me that I made a mistake, but I'm curious to know where, so I'll talk through what I did....

In the same testimony from Captain Rostron I linked earlier he says: "position 41.46 N., 50.14 W." confirming that he thought the Titanic's position was 41 deg 46 min North, 50 deg 14 min West. We know this position is inaccurate, but it is where he *thought* he had to go.

Then I used his quote "N. 52 deg. W., 58 miles", and added 180 to 52 = 232 degrees. Meaning that he thought his starting position was 58 miles away from the Titanic, at 232 degrees.

Then I plugged those into a Great Circle Calculator I found here: Javascript Great Circle Calculator

I used the second form on that page "Compute lat/lon given radial and distance from a known point". I changed the distance units from nm to sm because my understanding is that the "58 miles" was statue miles, not nautical miles.

When I did that the result was: 41:14.7525 North, 51:6.6508 West.

Finally I worked on the assumption that Captain Rostron would have been calculating based on a position to the nearest minute, so I used the first calculator on the page "Compute true course and distance between points" and played with different values rounded to exact minutes close to 41:14.7525 North, 51:6.6508 West to see which values looked closest to giving the N. 52 deg. W., 58 miles values for the course the Carpathia took.

41 deg 15 min North, 51 deg 7 min West gives the closes result I can find of all exact minute values in that area. The result is 58.06090621130972 Statute Miles at a bearing of 51.82068717232798 degrees.

I'm not saying that's where the Carpathia was, or that the end of that course was where the Titanic was, I'm just saying that, if I haven't made a mistake, then that should be where Captain Rostron *thought* he was when he changed course to rescue the survivors.

I'd be grateful if you could tell me why this is wrong.
 

Doug Criner

Member
Dec 2, 2009
411
38
98
USA
When you ask about "position measured by instruments," that would only be a celestial fix by sextant. After the last celestial fix, the ship's position is determined by dead reckoning, plotting the ship's course and speed. The last celestial fix would likely have been made at twilight on Sunday evening - everything after that would have been by dead reckoning. After the end of evening twilight, it would have been very difficult or virtually impossible to get a fix because of the lack of a sharp horizon to use for measuring a celestial body's altitude. There was no moon and starlight would not be adequate for revealing a sharp horizon.
 

Doug Criner

Member
Dec 2, 2009
411
38
98
USA
Samuel, maybe you know on what latitude the Carpathia was at around 10 p.m. April 14?
And maybe you know at what altitude was the Polaris at 3 a.m.?
Thanks.
The altitude of Polaris and Carpathia's latitude are one and the same.
 

Jon EH

Member
Jul 24, 2019
5
0
1
The Netherlands
When you ask about "position measured by instruments," that would only be a celestial fix by sextant. After the last celestial fix, the ship's position is determined by dead reckoning, plotting the ship's course and speed. The last celestial fix would likely have been made at twilight on Sunday evening - everything after that would have been by dead reckoning. After the end of evening twilight, it would have been very difficult or virtually impossible to get a fix because of the lack of a sharp horizon to use for measuring a celestial body's altitude. There was no moon and starlight would not be adequate for revealing a sharp horizon.
Yes, I meant sextant plus, presumably, naval chronometer for longitude.

I'm afraid I only know the theory (and I only know it roughly), I've never navigated myself. I though longitude was fixed at noon?
 

Doug Criner

Member
Dec 2, 2009
411
38
98
USA
Longitude at noon, OK. But your other post talked about latitude. And, the last celestial fix would have been at twilight on Sunday evening.
 

Julian Atkins

Member
Sep 23, 2017
1,017
464
93
South Wales UK
Hi Jon,

I suggest you do a search of 'Carpathia Dave Gittins' on here, and you will find many years ago a summary of his original web page article that is sadly no longer available. A summary is also in Eric Clement's biography of Rostron, with due acknowledgements to Dave Gittins.

I have been provided with a copy of Dave's original paper very recently, and I am sure if you ask Dave nicely he will help out, as will others. My own copy was provided recently privately, so I don't think I have permission to circulate it to others.

But it is pretty much all in Eric Clements' book, which is quite a good read and well worth having.

Rostron did not record the DR position when he made an about turn course to go on his rescue attempt, just the direction he aimed at and his projected distance to Boxhall's CQD position. When I say he did not record the position you would like, it is not recorded in his USA and British Inquiry testimony or a newspaper article or his own report to the Cunard Line.

If Brian Ticehurst has seen the original Ships Log of the Carpathia, then I am sure we would all wish to find out where it is and have a look. I am not too sure that Brian looked at it - merely quoting a reference of it with a few details. I don't recall anyone stating that they have examined the Carpathia's Ships Log Book in person. But I stand to be corrected on this. Dave Gittins does not state he had personally or via others examined it, and as far as I can conclude it is missing, but it would be a great find if it resurfaced in some archive somewhere. Brian Ticehurst's reference would equate to a Kew Archive reference, but I conclude it is missing same as The Californian's Ships Log.

Generally, the Ships Logs were retained by the Ship's Company in their archives, but some have come to light elsewhere as Tim Maltin's research has indicated.

Cheers,

Julian
 

Dave Gittins

Member
Apr 11, 2001
4,981
218
193
Since I'm being quoted, I'll put my oar in. The position of 41°10'N, 49°12'W was worked 20 years ago, using the traverse table and a universal plotting sheet. It's good enough for practical purposes. Rostron had evidently been pushed east by the North Atlantic Drift. The proposed real starting point is based on a realistic speed for his rescue mission and is open to debate.

A few other things for those less familiar with navigation. Rostron did not use statute miles at sea. Nor did anybody else.

The altitude of Polaris at 3-00am on April 15 1912 can't be known without a pile of old references. Polaris is not right at the North Pole. The distance varies over the years. In 1912 it was at 88°50'12", more than a degree off the celestial pole. To make an observation for latitude you need to know UTC and the position of Polaris in its circle round the Pole at the time. It's all in the Nautical Almanac.

Longitude was not fixed at noon. An observation gave latitude and an earlier celestial observation for longitude was carried forward by dead reckoning to give more or less accurate longitude. Lazy yachtsmen have been known to guesstimate longitude at noon by guessing the time when the sub reached its zenith, but that wouldn't do on a liner.
 
  • Like
Reactions: 4 users

Jon EH

Member
Jul 24, 2019
5
0
1
The Netherlands
Since I'm being quoted, I'll put my oar in. The position of 41°10'N, 49°12'W was worked 20 years ago, using the traverse table and a universal plotting sheet. It's good enough for practical purposes. Rostron had evidently been pushed east by the North Atlantic Drift. The proposed real starting point is based on a realistic speed for his rescue mission and is open to debate.

A few other things for those less familiar with navigation. Rostron did not use statute miles at sea. Nor did anybody else.

The altitude of Polaris at 3-00am on April 15 1912 can't be known without a pile of old references. Polaris is not right at the North Pole. The distance varies over the years. In 1912 it was at 88°50'12", more than a degree off the celestial pole. To make an observation for latitude you need to know UTC and the position of Polaris in its circle round the Pole at the time. It's all in the Nautical Almanac.

Longitude was not fixed at noon. An observation gave latitude and an earlier celestial observation for longitude was carried forward by dead reckoning to give more or less accurate longitude. Lazy yachtsmen have been known to guesstimate longitude at noon by guessing the time when the sub reached its zenith, but that wouldn't do on a liner.
Thanks!

Not saying Rostron used statute miles at sea, I'm saying he did in his testimony when he said he calculated the distance as "58 miles". Am I wrong on that point?

I think I must be.

Presumably I am somehow wrong about the course too!

If I put 58 Nautical Miles on a course of 232 degrees I get: 41:10.0062 North and 51:14.5166 West.

But then you say on your website "After considering these factors, Rostron decided that he was 58 miles from Titanic and that his course to her was 308° True."

Where do you get the 308° from?

I had 52° as I said above from his testimony "Yes, the true course was N. 52 deg. W., 58 miles from me when I turned her round. " (paragraph 25389 here: TIP | British Wreck Commissioner's Inquiry | Day 28 | Testimony of Arthur H. Rostron (Master, SS Carpathia))
 

Dave Gittins

Member
Apr 11, 2001
4,981
218
193
You appear not to understand the notation used in 1912. N 52 W means 52° west of north, which is 308° in modern notation.
 

Jon EH

Member
Jul 24, 2019
5
0
1
The Netherlands
You appear not to understand the notation used in 1912. N 52 W means 52° west of north, which is 308° in modern notation.
Thanks a lot! That explains it! So the opposite way round the angle was 128° making the starting point 41:10.0062 N 49:13.4834 W according to the app I'm using.

I'm happy with that, your result was obtained using methods close to those available at the time, whereas I am cheating, so I'm pretty sure that explains the small remaining difference.

I am still interested in reconstructing all the steps that led him to calculate that position.

I will read your article carefully when I have time and I'll probably have more questions after that.

Thanks again for clearing that one up for me!
 

AlexP

Member
May 23, 2019
355
16
18
Usa
Since I'm being quoted, I'll put my oar in. The position of 41°10'N, 49°12'W was worked 20 years ago, using the traverse table and a universal plotting sheet. It's good enough for practical purposes. Rostron had evidently been pushed east by the North Atlantic Drift. The proposed real starting point is based on a realistic speed for his rescue mission and is open to debate.

A few other things for those less familiar with navigation. Rostron did not use statute miles at sea. Nor did anybody else.

The altitude of Polaris at 3-00am on April 15 1912 can't be known without a pile of old references. Polaris is not right at the North Pole. The distance varies over the years. In 1912 it was at 88°50'12", more than a degree off the celestial pole. To make an observation for latitude you need to know UTC and the position of Polaris in its circle round the Pole at the time. It's all in the Nautical Almanac.

Longitude was not fixed at noon. An observation gave latitude and an earlier celestial observation for longitude was carried forward by dead reckoning to give more or less accurate longitude. Lazy yachtsmen have been known to guesstimate longitude at noon by guessing the time when the sub reached its zenith, but that wouldn't do on a liner.
Dave, could you please explain why both Captain Rostron and Sir Bisset described the first flare as being high. According to you it was just above the horizon.
 
Mar 22, 2003
5,500
801
273
Chicago, IL, USA
www.titanicology.com
>>The Official Carpathia Log Book No. 6. / No. 1 Board of Trade number 100/156 8437 consisting of 46 pages for 377 men covers the period from when the Carpathia set off from Liverpool on 10th February 1912 until she returned to Liverpool on 1st January 1913. <<

I wonder if he meant an official book of sign-on listings for Carpathia as opposed to the official log book?

10 Feb 1912 to 01 Jan 1913 is about a year of service. That period would imply well over 300 pages because In the early 1900s, a ship’s logbook was divided into individual pages for each day of a voyage.

A single logbook page ran from midnight to midnight. At the top of the page, the name of the vessel, such as 'RMS Titanic' would be written down along with the “From” and “To” ports of the current voyage (e.g., From Southampton , To New York), as well as the current day and date such as: “Sunday, 14th day of April , 1912.” The page was divided horizontally into two major parts, one for AM on top half, and one for the PM on the bottom half. Both AM and PM parts were each further subdivided horizontally into twelve one-hour segments, and data and remarks were listed in the appropriate columns for the hourly segment. In the middle of the page, separating the AM and PM segments, there was a printed section for recording noontime observations and other relevant pieces of information. Typically, in this middle section you would find space for such things as:
- Latitude and longitude at Noon by DR and by Observation
- Course and distance made good from last noontime position
- Distance through the water by patent log
- Currents in the 24 hours ending at noon
- Compass variation
- True bearing and distance to a given position at Noon
- Coal consumed and coal remaining

The columns of the logbook were typically marked for:
- Hour segment (1 through 12 in both AM and PM parts)
- Distance run in nautical miles and tenths of a mile
- Course by standard compass
- Standard compass deviation
- Patent log reading
- Revolutions per minute (on each engine)
- Wind: direction and force
- Weather (sky conditions, etc.)
- Sea state
- Barometer and attached thermometer
- Temperature: air, wet bulb, and sea
- Remarks

Specific time notations of key events would be entered into the Remarks column as required along with a brief description of the event that took place at that time. The time given would be Bridge time, the time on the wheelhouse clock used by the watch-keeping crew and GMT. Typically, entries in the temperature, barometer, weather, sea state and patent log columns would be made every two hours in hour segments 2, 4, 6, 8 and 12 in each AM and PM parts. Entries for engine revolutions would be made every four hours in hour segments 4, 8 and 12 in each AM and PM parts. Course changes would be entered into the Remarks column showing time of the course change and the new standard compass course.
 

Jim Currie

Member
Apr 16, 2008
5,069
641
213
Funchal. Madeira
Good posts.

In fact, back in 1912 and for very many years thereafter, a ship's navigator, would not have use a great circle calculation for a short calculation like the one under discussion, he would have used a formula from what was known as The Sailings and checked his answer using the Traverse Table. Nor would he ever have used ship time or New York Time but would have worked exclusively in GMT. In fact, at least one Junior Navigator on Titanic had his watch set to GMT.

In the case of Rostron; his man would have first worked a DR position for where they were at 12-30 am on the morning of April 15, as outlined by Doug. As I have pointed out before, this would have been fairly accurate since a mere 5 hours had lapsed since the last fix position had been obtained, and at that time they would have had a fairly accurate speed to use. Thus, they had two position to work with...the distress position and a fairly accurate 12-30 am DR position.
For the technically minded, they would have used these in conjunction with The Mercator Sailing formula. For urgency, they may have first used Traverse Table as indicated by Dave, or they would have made a proper calculation and checked the result by Traverse. it might have looked a little like the following:
calculating co an dist 2019-07-25 001.jpg

The distance by calculation is over half a mile greater than by Traverse Table, but perhaps i made a mistake somewhere. However good enough for illustration purposes.
 

Julian Atkins

Member
Sep 23, 2017
1,017
464
93
South Wales UK
I have quite a few views on all this, but may I once again thank Seumas for providing the wayback link (which I was previously unaware of despite an extensive online search), for a very important resource of Dave Gittins' original website. Dave Billnitzer's original website is similarly recorded. Hopefully both now for posterity!

The significance of Dave Gittins' own research I personally regard as of considerable importance.

Cheers,

Julian
 
  • Like
Reactions: 1 user

Similar threads