Previous related threads on this subject:
https://mb.nawcc.org/showthread.php?139057-Master-Navigation-Watches-A-9-A-13-5740-and-5740-1
https://mb.nawcc.org/showthread.php...econd-B-W-Raymond&highlight=master+navigation
https://mb.nawcc.org/showthread.php?100550-Hamilton-and-waltham-gct&highlight=master+navigation
https://mb.nawcc.org/showthread.php?136951-Elgin-A-13-Master-Navigation-Watch&highlight=AN5740
In the last few posts of the 1[SUP]st[/SUP] link above, evidence was beginning to build that in addition to the well-known "white dial" Elgin type A-13, that there was also a "black dial" Elgin A-13 variant. Military publication, AN 05-35A-5, dated 1 November 1944 titled:
Handbook of Instructions with Parts Catalog
Types A-8, A-11, A-13 and AN5740 NAVIGATION WATCHES
clearly defines the differences between a white dial Elgin A-13 variant, a black dial Elgin A-13 variant, as well as an Elgin AN5740 variant. It is noted on the cover that this handbook replaces T.O. NO. 05-35-18 dated 30 April 1942.
As can be seen from the attached 6 extractions from that Handbook, especially the 2[SUP]nd[/SUP] and 6[SUP]th[/SUP] attached JPEG files, it is clearly evident that there was indeed a black dial A-13 variant and that the part numbers for the dial and hands are different than those for the white dial A-13 variant or AN5740. Additionally, both variants of the A-13 used a case different (smaller and smooth) than the one used on AN5740. Elgin, Hamilton, and Waltham all built Master Navigation Watches during WWII, however, only Elgin built the A-13 variant.
Elgin's part numbers were as follows:
A-13, white dial, part number 1767
A-13, black dial, part number 1786
AN5740, part number 1790
Summarizing:
1. The characteristics of the A-13, it was the first variant to include the "hack" feature into the stem. Pulling out on the stem stopped the movement. The A-13 has either a white or black dial, with the minutes marked from 0-55 and the hours marked from 0-23. "GCT" is marked below the center of the dial. The hands are narrow, baton style. The case is smooth and slightly smaller than the cases used on the later variants.
2. Functionally, the AN5740 was identical to the A-13. The "AN" designated that the watch was to be jointly use by both the Army and Navy. AN5740 has a black dial with minutes marked from 5-60 and hours from 1-24. "GCT" is marked above the center of the dial. The AN5740 variant utilized a slightly larger case with knurling on the outside edge of the case. (Consequently the back case cover from an AN5740 will not fit the earlier A-13 case and vice versa.)
3. Later, post WWII, AN5740-1 came into existence. AN5740 had two subsequent revisions:
AN5740 rev 1
Publish Date: 15 March 1957
AN5740 rev2
Publish Date: 25 April 1961
From information supplied by Mr. C. N. Lloyd: "The AN 5740-1 only begins to show up on the subsequent contracts after 1948, when the last WWII contract was fulfilled. Beginning in 1952, a new contract was let for Navigation Master Watches, with Hamilton again chosen to fill them, still calling the watch by its AN 5740 designation. However, all of the later contracts of 1956, 1958, and 1959 will either have the cases labeled AN 5740-1 or Navigation Master Watch with the 33106 part number".
https://mb.nawcc.org/showthread.php?139057-Master-Navigation-Watches-A-9-A-13-5740-and-5740-1
https://mb.nawcc.org/showthread.php...econd-B-W-Raymond&highlight=master+navigation
https://mb.nawcc.org/showthread.php?100550-Hamilton-and-waltham-gct&highlight=master+navigation
https://mb.nawcc.org/showthread.php?136951-Elgin-A-13-Master-Navigation-Watch&highlight=AN5740
In the last few posts of the 1[SUP]st[/SUP] link above, evidence was beginning to build that in addition to the well-known "white dial" Elgin type A-13, that there was also a "black dial" Elgin A-13 variant. Military publication, AN 05-35A-5, dated 1 November 1944 titled:
Handbook of Instructions with Parts Catalog
Types A-8, A-11, A-13 and AN5740 NAVIGATION WATCHES
clearly defines the differences between a white dial Elgin A-13 variant, a black dial Elgin A-13 variant, as well as an Elgin AN5740 variant. It is noted on the cover that this handbook replaces T.O. NO. 05-35-18 dated 30 April 1942.
As can be seen from the attached 6 extractions from that Handbook, especially the 2[SUP]nd[/SUP] and 6[SUP]th[/SUP] attached JPEG files, it is clearly evident that there was indeed a black dial A-13 variant and that the part numbers for the dial and hands are different than those for the white dial A-13 variant or AN5740. Additionally, both variants of the A-13 used a case different (smaller and smooth) than the one used on AN5740. Elgin, Hamilton, and Waltham all built Master Navigation Watches during WWII, however, only Elgin built the A-13 variant.
Elgin's part numbers were as follows:
A-13, white dial, part number 1767
A-13, black dial, part number 1786
AN5740, part number 1790
Summarizing:
1. The characteristics of the A-13, it was the first variant to include the "hack" feature into the stem. Pulling out on the stem stopped the movement. The A-13 has either a white or black dial, with the minutes marked from 0-55 and the hours marked from 0-23. "GCT" is marked below the center of the dial. The hands are narrow, baton style. The case is smooth and slightly smaller than the cases used on the later variants.
2. Functionally, the AN5740 was identical to the A-13. The "AN" designated that the watch was to be jointly use by both the Army and Navy. AN5740 has a black dial with minutes marked from 5-60 and hours from 1-24. "GCT" is marked above the center of the dial. The AN5740 variant utilized a slightly larger case with knurling on the outside edge of the case. (Consequently the back case cover from an AN5740 will not fit the earlier A-13 case and vice versa.)
3. Later, post WWII, AN5740-1 came into existence. AN5740 had two subsequent revisions:
AN5740 rev 1
Publish Date: 15 March 1957
AN5740 rev2
Publish Date: 25 April 1961
From information supplied by Mr. C. N. Lloyd: "The AN 5740-1 only begins to show up on the subsequent contracts after 1948, when the last WWII contract was fulfilled. Beginning in 1952, a new contract was let for Navigation Master Watches, with Hamilton again chosen to fill them, still calling the watch by its AN 5740 designation. However, all of the later contracts of 1956, 1958, and 1959 will either have the cases labeled AN 5740-1 or Navigation Master Watch with the 33106 part number".
Last edited:
