"Pilots, Man Your Planes!"   
                                         WWII U.S. Naval Aviation Collector's Guide                                                                              
          AN-Aero. Standard
Below:  Due to the large numbers already in inventory, both the Army's S-1 seat parachute and the Navy Standard Seat parachute remained in service after their intended replacement, the AN-6510 seat parachute, became available. A shared feature of all three was a 24' diameter silk or nylon canopy. For larger airmen, the AN-6511 was provided with a 28' canopy (also found on the earlier Army S-2). Our Navy mannequin wears a Navy contract AN-6510-1, while our Army mannequin has an AN-6511-1 made under A.A.F. contract. With no observable differences in construction to be found on these standardized parachutes, the only way to distinguish between the two services is the contract number on the data plate. Although there may have been others, Navy contract AN type seat parachutes are confirmed to have been made by Switlik Parachute Company, Standard Parachute Company, Irving Air Chute Company and Pioneer Parachute Company, Incorporated. 
Above:  Seat cushions and and back pads were provided as part of  the parachute assembly. The seat cushions were marked with the same manufacturer's data and contract number found on the seat pack data plate, as can be seen on our Navy example, at left. Unfortunately, since they were removable, when found today, the cushion may have been replaced during the service life of the parachute, as is the case with our Army example. Note the manufacturer is different, National Automotive Fibres, Inc., and the contract (W-535-AC-26571) differs by one digit.

Below:  Raft, One-Man Parachute Type, Pneumatic Life, specification AN-R-2, type AN-6520-1

Prior to WW2, life rafts were routinely carried in Naval aircraft (including single seat types) but they were only accessable for use after ditching. The advantage of having a raft attached directly to the individual aviator became readily apparent when one contemplated the new combat environment and the grim prospects of bailing out over the vast waters of the Pacific Ocean with nothing more than a life vest to sustain you. After studying the survival equipment used by both combatant air forces in the Battle of Britain, the Navy developed its own specification M-524 one-man raft, complete with a carrying case featuring a center slot to accommodate the leg straps of the Navy standard seat parachute harness and began production in May 1942. This basic raft was also adopted by the Army (which had no equivalent at the time) as AN-R-2, but they designed there own case, without a slot, due to the Army seat parachute harness' shorter leg straps. Army production was begun in August 1942. Early examples of this style included fabric tapes to attach the case to the harness of a back or QAC chute if need be. Later examples used a parachute webbing strap with snap hooks and V-rings for attachment to the harness. Not until January of 1943 however, when Standard A was adopted, did true AN Standardization begin after the raft case was improved by moving the leg slot forward to within 2" of the front edge, allowing it to be used with the older Navy standard or Army S-1, as well as the newer AN-6510 seat parachutes. Found inside the case was the raft itself with directly attached CO2 inflating cylinder, one collapsible bailing cup, one bucket type sea anchor and an oral inflation tube. Additional emergency equipment items stowed in the AN raft case included two hand paddles, one can of sea marker, one can of emergency drinking water, two bullet hole plugs, one raft repair kit, one 5-unit first aid kit (a 6th unit, sulfadiazine tablets, was later added) and a 54" square rubberized fabric sail / tarp. Subsequent spec. AN-R-2B removed the sail when the M-592 back pad survival kit, which included a hooded poncho, became available for Navy use. The Navy also replaced the sea marker can with three life jacket dye markers in the spring of 1944. Some of this equipment was government furnished and some was contractor furnished, resulting in the many minor variations that occur. 

A number of sub-contractors were employed to manufacture the AN raft cases, so the raft and its case will not always be a product of the same company.
Background:  From the same Navy parachute manual, a list of all the AN-6510 related blueprints, dated 12/3/41. 

Below:  Prior to AN standardization, typical radio ear phone equipment for a Navy flier would consist of a "Type 49015, CTE Head Telephone Set, Helmet, Navy Specification RE 49A 118", which included two each "Type 49020 Cup-Telephone Mounting, Leather".  In the vernacular of today's militaria collector, this is better known as a "Telephonics TH-37 headset with leather ear cups". It was standard Navy issue from April 1933 until August 1942. Radio transmissions were made using either an NAF 213264-6 hand microphone or an RS-76 throat microphone. An Army flier would have used R-14 ear phones and a T-17 hand, or T-30 throat, microphone. As seen below, the A-N standard equipment that superseded these items was the now familiar AN H-1/AR headset, with two plastic-housing  ANB-H-1 magnetic earphones, connected in series by a 13" fabric covered "T cord", terminating in a red PL-354 plug*. These ear phones, being low impedance (300 ohms) were more reliable and less expensive to produce than the high impedance (2,000 ohm) R-14. The Navy had already been successfully using low impedance ear phones for nine years. The new AN ANB-M-C1 oxygen mask microphone was felt to be more practical to use and also allowed for clearer voice transmission than a throat microphone, although at lower altitudes, hand microphones were still commonly used in single-engine Navy aircraft and the enclosed-cabin, multi-engine, aircraft of both services. As a rule, Navy contract oxygen mask microphones will have a shorter cord than their Army equivalent. This appears to relate to the respective "push-to-talk" switch used by each service, that for reasons unknown, was never standardized.

*As you are probably already aware, the Navy also procured several Navy-specific versions of the H-1/AR headset, (all of which used ANB-H-1s with unique Navy cords and black NAF-215285-2 plugs) as well as headsets made by Perm-o-Flux and Telephonics with  metal-housing ANB-H-1A dynamic ear phones. None of these were adopted by the A.A.F., so they are not covered here.
Above:  A Navy contract (NXS-500) AN-6510-1, by Switlik and an Army contract (W535-AC-26572) AN-6511-1, by Reliance. Not shown here are the other two standardized parachutes, the AN-6512-1 back type and the AN-6513-1 quick attachable chest type.

Below:  Our Navy parachute is dated August 1943, while the Army one dates from July 1943. Curiously, the Reliance example was stamped with the part number for the pack assembly, rather than the parachute type, which was properly done on the Switlik data plate. Surviving examples show that at some point later in the construction run, this minor error was corrected by the manufacturer.
Below:  Before 1941, seat, back and chest parachutes were employed by both the Army and the Navy. The hardware and webbing used by each service was different, however. The Army harness was constructed of cotton webbing, characterized by a black or blue thread line down the center and having a tensile strength of 2,900 pounds. The strap attaching hardware was made up of male-female type fasteners that rotated to lock. The Navy harness was constructed of linen webbing having a tensile strength of 5,000 pounds. Attaching hardware consisted of snap hooks and V-rings. The new AN-Aero Standard harness was constructed of AN-JJ-W151 cotton webbing, as previously used by the Army, and nickel alloy, heat treated, and cadmium plated hardware, as used by the Navy. For seat parachutes, of which we are most concerned here, a seat cushion and back pad was provided, each made of cotton fabric filled with interlaced curled hair. The rectangular back pad held the harness straps in proper position, prevented tangling and simplified the operation of putting on the harness. The seat cushion, with a slot 2" from the forward edge to accommodate the harness leg straps, could be attached either directly to the top of the parachute pack, or above the pararaft case, if used. By most period accounts, it did little to improve the wearer's comfort on long flights.
Below:  A comparison of the accessories, to be found in the Navy (at left) and the Army (at right) versions of the raft, as published in the "Air-Sea Rescue Equipment Guide" from 1945. As previously mentioned, by this time, the Navy "B" version had  removed the sail, while in the Army "A" version, it was still included. The notation "C.F.E." stands for Contractor Furnished Equipment.
Above:  A survival equipment display done at NAS Norfolk in January of 1945 shows a Navy contract AN-R-2A with its accessories. This example was manufactured for The Goodyear Tire & Rubber Company by a sub-contractor in March of 1943 under Navy contract NXS-5599. In the past, authors and collectors alike have, understandably, been a bit unclear about the one-man rafts due to the variety of markings that can be encountered on the rafts themselves as well as their cases. The point to remember, as stated in the notes with the list of Navy accessories shown above is that "There have been no major design changes in the raft under specification M-524, AN-R-2, AN-R-2a and AN-R-2b.". So, if an aviator was sitting on a pararaft case marked "AN-6520-1" that held a raft marked "AN-R-2B", the only thing that concerned him was that it would work properly if the opportunity came to use it.

Below:  This is a perfect example of how the two services could take a "standardized" item of equipment, each make their own minor design changes, then label it with either the specification, drawing, part or type number to further confuse the issue. It doesn't help matters when the document below sites six different possible names for the same thing. The raft case shown at the bottom right of this page from the June 1944 "Index of Army-Navy Aeronautical Equipment MISCELLANEOUS" section was not used by the Navy, as it is the A.A.F. design without a slot for the harness leg straps, as mentioned above. Army recommendations, adopted in Standard A, included a blue bottom to the raft, the addition of the sail, first aid kit, an oral inflation tube to replace the rubber concertina-type topping-off pump used by the Navy (copied from the British) and flat cans of water and dye marker instead of the previous cylindrical ones.

Our many thanks to Dustin Clingenpeel for his help keeping us "on the beam" in relating the correct chronology of the often foggy realm of one man rafts.