Overview:
We covered the restoration of the internal structure for the SBD's life raft stowage compartment in Restoration Update #103. Mounted in the aft fuselage, just to the rear of the gunner's cockpit, this large compartment fitted a pneumatically inflatable U.S. Navy Type D rubberized raft which was capable of carrying at least two aircrew. It came equipped with oars, a separate bag containing emergency rations including fresh water, and, later in WWII, some even featured a "Gibson Girl" radio for communicating with potential rescuers. The aircrew - albeit not initially in WWII - also had survival packs with two canteens of water, food, a flare pistol (and flares) amongst other necessities for surviving a few days after a ditching at sea, although sometimes they had to endure weeks adrift before finding salvation... if indeed it eventually came at all!
This article primarily features the restoration of the compartment's fuselage access hatch/door, but we have also included a short section at the end which offers some details about the life raft itself, and how aircrew deployed and operated them during WWII.
The Hatch:
The three images below show the life raft compartment access hatch prior to restoration commencement. While the exterior skin was damaged beyond airworthy repair due to creasing and corrosion, the interior skin and mounting hinge proved salvageable. The door latch handle and its mounting mechanism needed refabricating, however.
A view of B-22's original life raft compartment door, revealing its interior structure. While some corrosion was evident on the inner skin, the part proved to be repairable. (image via Pioneer Aero Ltd.)
A closeup of the lower interior portion of the door reveals some corrosion near the hinge, but this was repairable to airworthy condition, as was the hinge itself. (image via Pioneer Aero Ltd.)
Refabricating the Latch Handle and its Mount:
The SBD's life raft compartment access hatch is opened and closed via a latch handle mechanism mounted atop the hatch's upper lip. Sadly, B-22's latch handle, while still attached to the Dauntless upon its recovery from Lake Michigan in September 1994, subsequently became separated from the airframe in the decades which followed. A replacement from a donor airframe was not available, so Pioneer's engineers had to refabricate it from original drawings, along with a new mount and pivot joint. Images in this section reveal some of the steps involved with making these parts.
The handle mount for the life raft compartment door comprises three pieces of steel. Here, the inner tang has been welded to the main plate during its refabrication. (image via Pioneer Aero Ltd.)
The door handle’s pivot is seen here having been folded into a box section from a piece of sheet steel, then welded and cut to the required shape. (image via Pioneer Aero Ltd.)
The life raft compartment’s door handle is made from a single piece of sheet steel folded into shape. With no original example on hand, in any condition, the manufacturer’s drawings were critical to it’s refabrication — a process captured part of the way through in this image. (image via Pioneer Aero Ltd.)
Another view of the life raft compartment door handle part of the way through its remanufacture. The sheet steel is been shaped over a custom-built mandril, curved and tapered to the drawing dimensions. (image via Pioneer Aero Ltd.)
The replacement life raft compartment door handle after the completion of its shaping process. (image via Pioneer Aero Ltd.)
A topside view of the replacement life raft compartment door handle after the completion of its shaping process. (image via Pioneer Aero Ltd.)
Restoring the Hatch:
Before beginning the restoration of this component, Martin Hedley first carefully separated its primary structural components, its exterior and interior skins. Sadly, the exterior skin, as already mentioned, was too badly damaged to restore to airworthy condition, but it did serve as a useful reference in remanufacturing its replacement. The interior skin, and the hinge, were both salvageable, however, and after cleaning and making some repairs, the parts were ready for painting and reassembly.
A view of the restored life raft compartment door together with its replacement handle mechanism. (image via Pioneer Aero Ltd.)
A view of the restored life raft compartment door during trial-fitting onto the fuselage. The compartment’s lefthand ring is clecoed against the fuselage skin interior to ensure its profile remains correct, thus allowing the door to be fitted. Note that the door’s newly-made exterior skin was still oversized at the time this image was captured. It will be trimmed to size once the matching hole in the replacement fuselage skin has been finalized; permitting an even gap around the door’s circumference once it is mounted. Note the streaky marks on newly-made exterior door skin, characteristics typically left by the English wheel tool used during its forming process. (image via Pioneer Aero Ltd.)
Refabricating and Trial-Fitting the Weather Seal:
To ensure that its hatch formed a weather-tight seal against the life raft compartment opening, a rubber sealing strip was fitted around the entryway, with strips of aluminum used to synch it firmly into position. The following images show the process which Martin Hedley followed in manufacturing and fitting this seal to the SBD.
The replacement weather seal and retaining strips are seen here in the process of being refabricated for the life raft compartment’s lefthand opening. (image via Pioneer Aero Ltd.)
Here the replacement weather seal, with its retaining strips, are in the process of being trial-fitted to the life raft compartment opening. The newly-restored door will mate up against the rubber to form a tight seal. (image via Pioneer Aero Ltd.)
Painting Parts:
With the aluminum parts for the life raft compartment now fully restored or refabricated, it was time to paint them. After proper preparation, the parts received a layer of primer paint to begin this process. Once that had cured, Pioneer then applied a top coat in an appropriate shade for the period.
Pioneer Aero’s paint booth showing a selection of SBD components in the process of being primer-painted. Bunched up on the left side of the image we can see, from left to right, part of the rear cockpit floor structure, part of the righthand ring for the life raft compartment, one of the compartment tube's skins, and the interior skin for the compartment door. Then, at image center, we see the compartment’s lefthand ring, mounts for the pilots rudder pedal heel trays, and the life raft compartment door’s outer skin. Towards image right, from left to right, we can see the life raft compartment tube’s other skin and the remaining sections of the compartment’s righthand ring. The parts are pictured here curing before receiving their exterior color coat. (image via Pioneer Aero Ltd.)
An image of the same parts after having received their top coat of paint. They were undergoing curing at the time this image was captured, but would soon be going back out into the hanger for the next stages in their respective assembly processes. (image via Pioneer Aero Ltd.)
Final Assembly:
Once the life raft compartment's aluminum parts had returned from the paint booth, it was time to fasten them together with rivets. Pioneer's chief engineer, Martin Hedley performed this task by first temporarily clecoing together all of the components forming the main tube assembly. He then riveted the end pieces for the tube's righthand side onto the two semi-cylindrical skin sections which form the tube itself, before riveting them to one another as well. The latter task was more complex, because Hedley had to place the domed rivets with their heads lining the tube's interior, instead of the opposite. This orientation was necessary in order to minimize the chance that anything stowed within the life raft compartment could snag on the rivets holding it together. However, this choice presented a challenge, since the confines of the compartment made it impossible to shoot rivets in the conventional manner, where the "set" in the rivet gun hammers against the rivet head while a bucking bar is pressed against the other end to form the tail. [As an aside for those who may not know, the "set" referred to here is a hardened steel tool at the working end of the rivet gun which has a tip surface contoured to the shape of the specific rivet type in use. Sets for domed head rivets have a concave indentation in the tip which conforms to their profile.]
Hedley had to "back-rivet" the fasteners instead, using the rivet gun to buck the tails, whilst supporting the rivet heads receiving attention using a specialized tool attached to a long, sturdy steel bar. This tool is depicted in one of the images below.
Here we see that the life raft compartment’s tube assembly has also been riveted together. Note that the rivet heads fastening its skins are located within the tube, rather than the opposite (which would have been easier to achieve). This minimized the chance that any object stowed within it might snag against them, which would definitely have occurred had the rivet tails faced inwards instead. To accomplish this, Martin Hedley had to shoot the rivets with the rivet gun’s set hammering against the rivet tails, whilst pressing a specialized tool against the rivet heads to support them inside the life raft compartment tube — a process called back-riveting. Note that the special tool is pictured in the image lying between the rivet gun and the tube. It is essentially a long, steel bar of substantial rigidity and accommodation for a universal head rivet gun set at one end (see the item with the concave tip poking upwards from the bar). (image via Pioneer Aero Ltd.)
Here we see life raft compartment’s hatch part way through being riveted together. Because the ring of rivets around its circumference are so close to the skin’s edge, a different kind of riveting process had to be employed (to minimize the possibility of skin distortion occurring). Pioneer used a pneumatic, crocodile style rivet squeezer to buck these fasteners (see the red-painted device in the image). The device’s fixed jaw is held against the rivet head, whilst the other jaw articulates like a crocodile’s to squeeze the rivet tail flat. (image via Pioneer Aero Ltd.)
Here we see that the life raft compartment’s hatch has been riveted together (its hinge and interior skin structure are original to B-22). After riveting, Pioneer’s engineers applied another layer of top coat paint to cover the rivet tails and provide a more even coverage. (image via Pioneer Aero Ltd.)
A view of the life raft compartment hatch’s exterior following final-riveting. Its outer edge will be trimmed-to-size once the hole to accommodate it in the fuselage skin has been cut. This will ensure an even gap around its circumference. The four holes visible at the top of the hatch will hold the door handle, which will be riveted in place after the hatch perimeter has been cut to the correct dimensions. (image via Pioneer Aero Ltd.)
Inflatable Life Rafts for Aircraft in WWII:
This section is designed to provide a few details about the inflatable life rafts and survival kits which many U.S. military aircraft carried during operations over water in WWII. A number of companies designed and manufactured such craft in that period, with the Goodyear Tire & Rubber Company being one of the major suppliers. Founded in Akron, Ohio during 1898 the firm had a long history with the manufacture of rubberized products, it made sense that this company would be well-positioned to produce inflatable life rafts. [As an aside, Charles Goodyear, who discovered the vulcanization process which turned natural latex tapped from rubber trees into the durable, flexible material all of us are familiar with today, was not a founder, but the company was named in his honor.] Goodyear built thousands of life rafts for the U.S. Navy every week during WWII. These rafts were typically fabricated from a durable multi-ply, rubber-impregnated duck canvas, which was both durable and highly flexible so the rafts could be stowed easily in compacted form. Most readers will already know that Goodyear employed a similar technique, albeit with rubber-impregnated cotton, to manufacture the envelopes used in their military blimps, civilian variants of which still serve in small numbers today.
Goodyear employees completing the manufacture of dozens inflatable life rafts in the "balloon room" at a plant in Akron, Ohio circa 1942. (image via National Museum of Naval Aviation)
During peak production, Goodyear was producing thousands of inflatable life rafts per week. Here we see stacks of single occupant units inflated for testing in one of Goodyear's factory buildings in Akron, Ohio circa 1942. (image via NARA)
Operating the Life Raft:
While the images below feature a U.S. Army Air Forces pilot during training operations where he is learning how to operate his life raft, the principles were the same for naval aircrews during WWII.
A wartime image of a U.S. Army Air Forces pilot is seen here activating the C02 canister to inflate his life raft during a training session. With a one-man raft, inflation took roughly a minute to complete. Note that the bottom of the raft is blue. This was so that the downed airman could flip the raft over to camouflage it in case an enemy aircraft attempted to fire on it, a not uncommon occurrence in the Pacific war, sadly. (image via NARA)
With his life raft fully inflated, the pilot prepares to hoist himself aboard. (image via NARA)
Latching his arm under the seat flap, the airman hauls himself aboard the life raft. It was not an easy ordeal! (image via NARA)
The trainee attaches a hand pump to a nipple to help inflate the seat in his life raft while a safety diver looks on and explains what his student has to do. (image via NARA)
Trainee aircrew are seen hear learning how to capsize their life raft. While this served a good purpose in helping the men learn how to recover from such a situation should they encounter stormy seas and overturn accidentally, it also helped them learn how to tip it over deliberately should they need to disguise themselves from marauding enemy fighters which sometimes deliberately straffed stranded aircrew. (image via NARA)
Here the trainees are learning how to right their life raft, using the painters attached to its sides. Note that the bottom of the vessel is painted blue to help disguise it from marauding enemy aircraft, and sometimes from enemy shore batteries and small arms fire. (image via NARA)
750 miles over 34 Days Aboard a Raft in the Pacific:
One of WWII's great survival stories features the exploits of a Douglas TBD Devastator crew from VT-6 aboard USS Enterprise. Following a reconnaissance mission in the South Pacific on January 16, 1942, they were unable to relocate their carrier, and the mission's strict rules of radio silence prevented them from calling up the fleet to assist their navigation. Their aircraft, TBD-1 Bu.0335, eventually ran out of fuel, forcing the pilot, ACMM Harold Dixon, to ditch. He and his fellow aircrew, AOM2c Tony Pastula (bombardier) and RM3c Gene Aldrich (radio operator) survived the ditching unscathed, but the aircraft sank suddenly before they had been able to inflate their raft... taking their carefully arranged survival gear and rations with it too. While there is insufficient room to cover their harrowing experiences floating for 34 days, while navigating their vessel, as best they could over a 750 mile journey over open water to the Cook Islands, a marvelous April 2011 Smithsonian Magazine article by Alvin Townley, Stranded at Sea, recounts it in vivid detail; it is well worth reading! It is a story of immense courage and camaraderie which shows the resilience some people are able to summon when all appears lost. All three men received decorations for their extraordinary feat of seamanship and survival, Dixon receiving the Navy Cross. Their tiny 4 foot by 8 foot Goodyear-built life raft is presently on display at the National Naval Aviation Museum in Pensacola.
