“Border TBM Avenger” (San Diego, 105 fsw)

After Tyler and I dove the Missile Tower, we headed over to a relatively unknown TBM/F Avenger wreck.

It sits in about 105 feet of water and is close to the border near Imperial Beach. The wreck was originally located around 2002 by Roy Pettus, a local San Diego underwater archaeologist, during a survey for the Imperial Beach outfall.

The Wreck

The wreck site is pretty much a debris field. Based upon how broken up and distributed the wreck is, I’m guessing that it was a fairly violent crash. There are a few distinct areas of the debris field (1) The massive Wright R-2600 Twin Cyclone engine, (2) a part of the wing which currently has a “ghost net” on it, and (3) a debris pile with various plane parts.

The Engine

The Avenger used a Wright R-2600 Cyclone radial engine. The engine had two rows of 7 cylinders each for a total of 14 cylinders. The cylinders on each row are offset from each other. In the photos below, you can’t get a sense of how big the engine is, but it is massive. Also note how long the propeller is. I’ve included some screenshots of a photogrammetry model I built.

Fuselage

On the day we dove the wreck, there was a relatively recently snagged net on a section of the wing. The floats were still on the net and suspending it in the water column. There were also remnants from some older nets.

Debris

There are various debris areas around the site with some identifiable parts:

Oil cooler

Based on the location in the debris field, below is a picture of what we believe is part of the rear landing gear assembly:

Rear Landing Gear Assembly (?)

Wreck Identification

We attempted to identify the wreck based upon what we knew (aircraft type, location). It isn’t a lot to go on.

Given the condition it is in, it would be very hard (and very unlikely) to find definitive proof of the specific plane (Bureau ID, etc.). Tyler located some information for a TBF that crashed in that general area:

War report diary entry

The “location” coordinates are not obvious. After some research and general brute force trial-and-error, I think we have discovered the “key” to the information. It is shorthand to refer to a grid section in a general area. Since they reference Coronado Islands, it would equate to the decimal portion of 32 degrees north and 117 degrees south. For example, “4625” would equate to 32.46 N, 117.25 W.

Given that information, if you plot the last 3-4 sightings, it is obvious that the plane was headed North from the Coronados Islands towards the Naval Air Station.

The accident report below also mentions flying in that direction and happening in that general location:

Accident Report

In addition, we have copies of the war report diaries from the next few days when they were searching for the crew:

In the report from 25 May 1943, they report that “A body, identified by the name in a jacket as that of the pilot of the TBF which has been reported missing since 20 May and last reported near the Coronados Islands, washed ashore at Imperial Beach. The pilot was Lieutenant (jg) TAYLOR.”

Tyler also located a newspaper article about the pilot of that aircraft being found off Imperial Beach.

We will likely never be 100% sure without recovering something specific about that aircraft.

Given the location of the wreck site, the type of aircraft, the direction of heading of the above TBF and the location where the pilot was found, we conclude that there is a reasonable chance that this is the wreck of TBF #06476 on May 20/21, 1943 that involved three fatalities.

Second Dive

Tyler and I went back in mid-July to see if we could identify the aircraft. Our plan was to remove the growth around the engine cowling to find the identification plate. You can see it on the lower section of the grey cover plate in the photo below.

We attempted to find it; however, the cowling had eroded away exposing the parts underneath.

We also found a cool plexiglass section which we believe was the ventral gun window (i.e., the window through which the rear gun stuck out). Also note that ash and charred parts on the bottom right.

We believe this is either the O2 tank or the fire extinguisher:

Oxygen Tank or Fire Extinguisher

One of the primary landing gear assemblies with the large hydraulic arm is clearly visible over by the net which is on a section of the wing:

Primary landing gear assembly

There was definitely evidence of a fire as there were burnt pieces everywhere and some ash in the debris field.

Conclusion

We doubt that we will ever be able to find 100% positive proof of the specific aircraft at this wreck site. A lot of the wreck is also buried in sand making it hard to locate anything that might give us more clues. We don’t currently plan on conducting any more dives on this specific site.

2 thoughts on ““Border TBM Avenger” (San Diego, 105 fsw)

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