A Tale of Four Ships - April 1912
Tracking the Courses of the Californian, Carpathia, Mount Temple and Titanic
The chart below shows the planned tracks across the Atlantic of four ships: Californian, Carpathia, Mount Temple and Titanic. (Track of Mount Temple was modified
enroute to a more southerly track taking it well past the corner point [42°N, 47°W] to avoid reported ice. The
Californian planned to stay on 42°N from the corner till
51°W before heading up to Boston.)
Below is a chart of the area [reproduce from my THS Commutator article] extending from 40° 30'N to 43° 40' N, and 46°W to 52°W.  Included is a set of possible current
vectors that were modeled somewhat after modern satellite data as explained in the article. Near the center of the chart, centered about 41°
40'N, 49° 25'W, is placed a cold
water eddy with the usual counter-clockwise circulation with a core that is about 40 nautical miles in diameter. Feeding into this is a strong Labrador current out of the north
which is converging with a somewhat meandering Gulf Stream current flowing from the west, looping around southward, and finally veering off the north-northeast on the eastern
side of the eddy. Included on the chart are tracks of four ships:

- The DR track of Californian with its reported noon location at 42° 05'N, 47° 25'W, and heading 269° true from there toward 42° N, 51° W as reported by Capt. Lord in his
1959 affidavit.
 
-
The  DR track for Titanic is  off of a derived 7:30 p.m. ATS celestial fix position (corrected for a 15' longitude error) at 41°52.5'N, 47° 53'W, and heading 266° true from
that fix.

-
The DR track of Carpathia with her DR location for 12:35 a.m. ATS at 41°10' N, 49° 13' W, where she altered her course to  308° true (N52W) for the Boxhall CQD
(SOS) position at 41°
46'N, 50° 14'W. Prior to that, she was on a Great Circle course toward a point due west of Gibraltar.
- The DR track of Mount Temple with her DR location for 12:26 a.m. ATS at 41° 25'N, 51° 14'W, the time when she altered her course to a heading of 065° true (N65E) for
the CQD position. Prior to that she was on rhumb line to Cape Sable Island from 41° 15'N, 50° 00'W having come down there from the corner to avoid reported ice.

For a complete explanation of how the local current may have affected the course of each ship in the region, please refer to my THS
Titanic Commutator (No. 177) article,
"Light on the Horizon," Part 1.-
Shown below is a summary diagram of funnel colors used on steamers in 1912.  Funnel colors were often used to easily identify the steamship line that a steamer belonged to
when first seen at a distance.