History of US Signal MIrror Development in WW II

The attached 7 page article is both the most detailed article, and describes the most thorough signal mirror testing, that I've seen.

It describes the evolution of signal mirror sighting methods to the use of retroreflective aimers, and the test results that caused the US Navy to switch from the "rearsight" method (still common in lifeboat mirrors to this day) to retroreflective aimers.

I obtained this through the kind offices of the US Coast Guard historian.

A complementary overview of signal mirror development across this period (with lots of color photos) may be found here:

http://www.usmilitariaforum.com/forums/index.php?showtopic=2412

Wow..that was a great bit of history.i remember back in the 50's when as a kid i would see bins of those still in the wrap at the local surplus store.

Great article. Thanks for posting.

Yes, according to some 1946 Congressional testimony, over 1,000,000 were ordered in WWII, so I imagine there was quite a surplus glut after the war. I think I've even seen a 1950's survival book suggest picking one up.

Here's an ad in the Sept 1946 Popular Mechanics (top right corner) advertising surplus GE "cross-in-glass" signal mirrors for $1.
http://books.google.com/books?id=seADAAAAMBAJ&pg=PA279
( You can zoom in with the "magnifying glass" icon)

$1 back then corresponds to $10.62 today, according to http://research.stlouisfed.com/fred2/data/CPIAUCNS.txt

There was quite a bit of surplus after the war, not just of signal mirrors, but of nearly everything else. It was still so common fifteen years after the war, that my first sleeping bag and tent, were milsurp, among many other items.

a dollar was $10 in those days? it's been so long i forget just how much my allowance was and what i spent it on.if they were a $1=$10 that why i did not buy one but just looked!

Those were the days when, if you saw a penny lying in the street, you actually picked it up. It had reasonable value.

I still pick up pennies.

I figure that it takes about a second to pick up a penny. A penny a second is $36 an hour. A much more than reasonable wage for the task of picking up pennies.

A mirror and a whistle are useful addition to any kit.

There was a remarkable surge of effort in the United States to perfect and deploy signaling mirrors that began in September 1942 when the U.S. Coast Guard, Office of Strategic Services, and the National Inventor's Council approached the National Bureau of Standards for assistance in designing a practical signaling mirror for life rafts.

(see the March 1946 article attached at the start of this thread)

What set this off?

Two 1944 books about the US Coast Guard both suggest it was a single dramatic event, using the phrases:

"... That gave us the idea of adding mirrors" and
"... a few of them can be traced to individual occurrences"

Signal mirrors were not unknown - they were already standard issue in Navy life rafts.

For example, in the British Signal mirror test report H/Eq/249 from the Marine Aircraft Experimental Establishment, St. Helensburgh "Heliograph mirrors for emergency dinghies", issued on Oct 9, 1942 (after the NBS was approached, and before Rickenbacker went down) amongst the 13 mirrors the British tested in May and August 1942 was test mirror "G":

"Standard U.S. dinghy equipment No sighting hole" which the report says was a 4 inch chrome-plated brass mirror.

The article on pages 44-45 of the Feb 1, 1943 issue of Naval Aviation News ( a service magazine sent to Navy pilots) reinforces that:

"Life rafts in service and under procurement are equipped with a chromium plated steel mirror for use as a signalling device."
which at the time was "provided with a 1/8" hole near the edge", and is depicted as a round mirror on page 45.

What instigated the fresh interest? Some accounts point to the massive publicity associated with the Rickenbacker search and rescue, but Rickenbacker went down in mid-October 1942, a month after the National Bureau of Standards project began.

Richard S. Hunter of the National Bureau of Standards alludes to prior events in his March 1946 article: "A number of reports were published, at about the time of the Rickenbacker search, of survivors from ship sinkings and downed aircraft who had successfully improvised methods of reflecting flashes of sunlight toward searchers from tin-can bottoms or other shiny objects."

====================================================

This account from the US Coast Guard Official History suggests a single incident was the cause:

From:
Marine Inspection , December 7, 1941 - July 18, 1944 (Volume 13 of the Coast Guard at War Official History Series).

http://www.uscg.mil/History/articles/CGWar_13_Marine_Inspection.pdf


THE COAST GUARD AT WAR DEC 7, 1941 - JULY 18, 1944 MARINE INSPECTION VOLUME XIII
PREPARED IN THE STATISTICAL DIVISION U.S. COAST GUARD HEADQUARTERS JULY 31, 1944

SIGNALING MIRRORS

Occasionally a survivor would have an idea for adding something new to the lifeboat equipment. "There's one case where survivors told us how they signaled to a passing ship by tearing off the lid of a tin can and catching the reflection of the sun on its surface," the Captain related. "That gave us the idea of adding mirrors to the lifeboat equipment, along with the parachute flares and other signaling devices." New safety measures adopted by the Coast Guard are based squarely upon the experience and need of survivors, and after consultation with maritime unions and others concerned.

=================================================
This other 1944 book also suggests a single occurence:

http://www.archive.org/stream/firstfleetthesto011061mbp/firstfleetthesto011061mbp_djvu.txt

Full text of "First Fleet The Story Of The U S Coast Guard At War"

The Story of the U. S. Coast Guard at War-

REG INGRAHAM

INTRODUCTION BY SECRETARY OF THE NAVY FRANK KNOX

THE BOBBS-MERRILL COMPANY

Publishers
INDIANAPOLIS NEW YORK

pp. 260-261

"The majority of the Coast Guard's wartime safety measures are based on careful analysis of the experiences and recommendations of a large number of survivors, but a few of them can be traced to individual occurrences.

One group of seamen, for instance, came ashore after a protracted period in a lifeboat and it was discovered they had been overlooked repeatedly by patrol planes.

"We could see the PBY's [Navy flying boats] go by," they related, "but we were unable to attract their attention."

Finally one of them hit on an idea. Taking the bottom of a tin ration can, he fastened it to the blade of an oar and used it to flash the sun's rays back at the planes. This crude heliograph proved effective, too, and soon thereafter the Coast Guard made it mandatory for all lifeboats to be equipped with polished steel signaling mirrors. They are somewhat more elaborate, of course, than the piece of tin can fastened to an oar blade, and each mirror is accompanied by simple instructions for sighting it so as to give the maximum chance of the signal being seen. "

========================================
The text above was also verified by searching each paragraph to verify it as being present in the Google Books online "snippet view" version here:

http://books.google.com/books?id=zRnTAAAAMAAJ

Title First fleet: the story of the U.S. coast guard at war
Author Reg Ingraham
Publisher Bobbs-Merrill, 1944
Original from Indiana University
Digitized Mar 17, 2009
Length 309 pages

Here's a recently posted series photos of a World War II 4"x5" tempered glass ESM/1 emergency signaling mirror
and the instructions on the box.

Click on any photo for a larger view. Find the "full size" link on the resulting page to see an even larger view.











( For more photos of old emergency signaling mirrors, there's my photo gallery, too.

http://www.richard-fowell.fotopic.net/c1663439.html

Similarly, there's a "full size" button
if you want to see photos even larger than the ones resulting from clicking on the thumbnail photo.)

I obtained this WWII training film:

"Emergency Rescue Equipment - the Signaling Mirror"

from the US National Archives, and put it on YouTube - here it is.

( I kept the movie leader to preserve the ambiance - the film starts 11 seconds in.)

For a finer movie experience, I suggest you go to the video on YouTube itself by either double-clicking on image here at the ETS forums, or using this URL:

http://www.youtube.com/watch?v=vmnRrCVBaP0

and use the icons at the bottom right of the YouTube frame to select 480p quality and full screen (the 4-arrow icon)





I believe this is the signal mirror training film first previewed on August 3, 1943, describing how to use the ESM/1 mirror using the aiming principle invented by Larry L. Young of the National Bureau of Standards and implemented by Wentworth M. Potter of General Electric. of General Electric.

The film title screens indicate this was produced by the Office of Strategic Services (OSS) Field Photographic Branch, for the Liaison Committee on Emergency Rescue Equipment established by the Joint Chiefs of Staff (ERE), and the mirror it spends most time on is the General Electric "cross-in-glass" mirror. This all matches the reference I found [5] to the August 3, 1943 film, including the "80,000 per month" figure at 01:15 into the clip.

Here are the historical references I've found:

In his March 31, 1943 report[1] on the Miami trials of the prototype of the GE mirror implementing the cross aiming device invented by Larry L. Young of the National Bureau of Standards [2][3], Lt. Commander Earle F. Hiscock "strongly recommended" that "a motion picture be made, if possible, to illustrate the mirror and the proper method of holding."

The June 5, 1943 Recommendation No. 2 [4] of the Liaison Committee on Emergency Rescue Equipment that the tempered glass signal mirrors made by General Electric be procured for all airborne and Marine Services also recommended that" brief movie shorts" be prepared to instruct personnel.

The August 12, 1943 report of the Liaison Committee on Emergency Rescue Equipment [5] mentions that "A preliminary showing of the instruction film on the signaling mirror, in preparation by Field Photographic of the OSS, { Office of Strategic Services - Ed.] was run off on Tuesday 3, August" and also mentions the "80,000 per month" figure mentioned in the film I found at the National Archives.

The October 1944 issue of the Air Sea Rescue Bulletin [6],[7] appears to mention that this film is in their library.

The record at the US National Archives for the film I found and put on YouTube [8] seems consistent with my hypothesis.

[1] Letter from Lt. Comdr. Earle F. Hiscock, Principal Traveling Inspector; to: Chief, Merchant Marine Inspection, March 31, 1943; Subject: Tests on lifesaving and other rescue equipment at Miami, Florida, from 22 March to 26 March inclusive (letter at the US National Archives)

[2] "Heliographic Signaling Mirrors", by Richard S. Hunter
Pages 24-29, 48 Air sea rescue bulletin. v.3 no. 3 1946 Washington, D.C.

http://babel.hathitrust.org/cgi/pt?id=mdp.39015010566720;seq=86;view=image

"Within a few days of the receipt of the request for assistance, however, L.L. Young, then of the Bureau staff, had devised the rearsight method for aiming mirror flashes, and had shown that it was accurate and could be readily provided for in the manufacture of small mirrors."

[3] Larry L. Young US Patent 2395605 Feb 1946 "Light-Directing Device" Filed Dec. 7, 1943 { Clearly the mirror design in this training film }

http://www.google.com/patents?id=pqVWAAAAEBAJ

[4] Number 2, Emergency Rescue Equipment, Coordinator of Research and Development, U.S. Navy and Liason Committee of Emergency Rescue Equipment (established by the Joint U.S. Chiefs of Staff) June 5, 1943.

"Two companies are not prepared to manufacture tempered glass signaling mirrors, which tests show, are satisfactor as to general type and quality.
These companies are the General Electric Company and the Pittsburgh Plate Glass Company.
It is recommended that immediate steps be taken to procure such tempered glass signaling mirrors for the use of all airborne and Marine Services.
It is further recommended that the Services take steps to instruct their personnel in the use of this mirror by practical demonstrations, brief movie shorts, or other graphic methods."

[5] "Further Developments in Emergency Rescue Equipment Already Recommended:
Signaling Mirror, tempered glass type, Recommendation No. 2"
{ see [5] - Ed.}, page 6,
Bi-Weekly Report No. 3, August 12, 1943, Emergency Rescue Equipment, Coordinator of Research & Development, U.S. Navy and Liaison Committee on Emergency Rescue Equipment (Established by the Joint U.S. Chiefs of Staff),
Emergency Rescue Equipment Section, Room 2500,
Temp. Bldg. A, 2nd and T Streets, S.W. (limited distribution)

"A preliminary showing of the instruction film on the
signaling mirror, in preparation by Field Photographic of the OSS, { Office of Strategic Services - Ed.] was run off on Tuesday 3, August, for the information of some of the people who attended the Special Meeting (see Item I).

A recent check of procurements for the signaling mirror indicates that the following requisitions have been recieved
at Wright Field.

Bureau of Ships 200,000
Army Air Forces 275,000
Army Ground Forces 40,000
Bureau of Aeronautics 20,000
(Bought through contractor)

The General Electric Company and the Pittsburgh Plate Glass Company are prepared to make delivery at the rate of 80,000 mirrors a month."

[6] October 1944 issue of the Air Sea Rescue Bulletin, V1N4, p. 54
http://babel.hathitrust.org/cgi/pt?seq=3...;u=1&num=54

listed as "MG-3324: "Signaling Mirror", "Describes the aiming principle, and steps in the operation of the tempered glass emergency signaling mirror (ESM/1) with the cross aiming device", 15 minutes running time. The footnotes
translate to: "date of release unavailable", "Motion picture produced by Coast Guard or Government Agency other than Army, Navy, Marine Corps, or Office of Education".

[7] loc. cit, page 50
http://babel.hathitrust.org/cgi/pt?seq=40;view=image;size=100;id=mdp.39015039408987;q1=mirror;u=1;num=50;page=root;orient=0

[8] Here is the entry from the US National Archives for the film I found:
-------------------------------------------------------------------------------------------------------------
U.S. NATIONAL ARCHIVES & RECORDS ADMINISTRATION
-------------------------------------------------------------------------------------------------------------
Description 1 of 1
SIGNALING MIRROR, THE: EMERGENCY RESCUE EQUIPMENT, ca. 1941 - ca. 1945

ARC Identifier 39989 / Local Identifier 226.B6087

Moving Images from the Joint Chiefs of Staff. Office of Strategic
Services. Field Photographic Branch. (01/04/1943 - 10/01/1945)

Motion Picture, Sound, and Video Records Section, Special Media
Archives Services Division, College Park, MD

Item from Record Group 226: Records of the Office of Strategic
Services, 1919 - 2002

Details Creator(s): Joint Chiefs of Staff. Office of Strategic
Services. Field Photographic Branch. (01/04/1943 - 10/01/1945)
Type(s) of Archival Materials: Moving Images
Contact(s): Motion Picture, Sound, and Video Records Section, Special
Media Archives Services Division (NWCS-M), National Archives at College
Park, 8601 Adelphi Road, College Park, MD, 20740-6001. PHONE:
301-837-3540; FAX: 301-837-3620; EMAIL: mopix@nara.gov.

Coverage Dates: ca. 1941 - ca. 1945
Part Of: Series: Motion Picture Films, compiled ca. 1942 - ca. 1945
Use Restriction(s): Undetermined

Specific Records Type(s): motion pictures (visual works)
General Note(s): Filmographic title.
Contributor: Producer, Liaison Committee on Emergency Rescue Equipment

Sound Type: Sound

Variant Control Number(s): NAIL Control Number: NWDNM(m)-226.B6087

Index Terms: Subjects Represented in the Archival Material:
Contributors to Authorship and/or Production of the Archival Materials:

Department of the Navy. (1798 - 09/18/1947), Sponsor
Joint Chiefs of Staff. Office of Strategic Services. (06/13/1942 -
10/01/1945), Distributor

Lifecycle Tracking Information
Accession Number(s): NN3-226-88-2

Scope & Content
INSTRUCTIONAL FILM: Demonstrates use of small, hand held glass mirrors
as signaling devices for lost service persons. Gives instructions for
and demonstrates sturdiness, maintenance, operation. Explains
construction. Uses illustrations to explain aiming principle and
effective range.
Copies
All Copies Copies 1 - 1
Copy 1
Copy Status: Preservation
Contact(s): Motion Picture, Sound, and Video Records Section, Special
Media Archives Services Division (NWCS-M), National Archives at College
Park, 8601 Adelphi Road, College Park, MD, 20740-6001. PHONE:
301-837-3540; FAX: 301-837-3620; EMAIL: mopix@nara.gov.

Media
Media Type: Film Reel
Color: Black-and-White [color:#3333FF][/color]