PBM Mariner Debris Field Exploratory Dives (San Diego, CA)

Background

After our second dive on the PBM Mariner, we spent a little time scanning the surrounding area to look for more debris. Tyler had found the tire section a short distance away and we had a feeling there might be more. Lora’s new sidescan and sonar system on the Marissa are really beneficial when looking for small debris fields.

Tyler was working so I was out alone and the surface conditions weren’t great and we had a gloomy overcast day, but we were determined to make a good day of it. Lora had stopped off to pick up some muffins and croissants from a local bakery to do some taste tests and Chris and I were glad to offer our services.

The Plan

The plan was to re-scan some of the targets and then dive a few of them to see what we could find. Below is an image of the areas we had marked and what we ended up diving. Details of what we found are below.

Target #1 and #3

Although the surface conditions were a bit bumpy with some long period swells mixed with some wind & chop, the conditions under the water were amazing. Visibility had to be 40-50 feet. It reminded me of the day that Tyler and I got on the PC-815 when you could just see forever (relatively speaking).

When I first dropped down, I saw something sticking up and I thought it was a propeller from an airplane but was also confused since both props for the PBM are by the wing. Had I found a new wreck?! Upon closer inspection, it was a piece of rope sticking up from a metal structure with some growth on the end.

There are definitely concave sections of this piece of debris and there appears to be a ladder in one of the pictures.

We believe that this is the rear tail section of the PBM fuselage. The shape is very unique and we know there were some ladders near the tail section of the PBM.

Note that we ended up “re-diving” this same debris area for the third dive (this wasn’t on purpose, but we had multiple sonar images from the same general area). I tied a line in to the debris and did some exploring but didn’t find anything else.

Target #2

For the second dive, we decided to check out one of the areas we had previously marked that was closer to the wing area. I dropped down to see what I would find. The visibility had started to deteriorate but was still very good.

The first piece I ran into was possibly a piece of the pontoon, but we are unsure and I unfortunately didn’t get any specific measurements to help with the analysis.

When the accident happened, the right wing hit the water and the pontoon was ripped off and then the left wing hit and that pontoon was also ripped off. We also have a newspaper article that shows a picture of one of the pontoons and some of the crew and the article indicates that both pontoons were recovered.

Note that in the newspaper clipping, the gentleman on the right is resting his hand on the back of the pontoon and there is what appears to be a flat area. It is possible that this piece that I found is what mounted the pontoon to the wing.

However, the piece also has a squared-off and slanted end and the holes don’t seem to match the mounting points for the pontoons.

So, the piece I found could be section of the pontoon or from some other area on the aircraft or even possibly an internal piece that was designed to fit the inside contour. Steve Lawson thinks it might be the “end cap” on the very rear of the fuselage.

For now, we will need to consider it an unknown but given the location, related to the PBM Mariner.

After returning to the down line, I noticed another shadow off in the distance so I went to investigate that. We believe that the pictures below are from the “bow” of the fuselage section. You can see the intricacy of the support beams and the shape of the “bow” structure.

If you look closely at the photos (especially the lower right), you will note what looks like a rope attached to a loop buried in the sand at what would be the “top” of the bow (it is upside down). You can also see that in the black and white historical photos. We have seen that same setup in multiple historical photos and I’m guessing it was used to hold the plane when it was “docked.”

Thanks

A special thanks to Lora, Chris, Captain, and Scout for a fun day of exploratory diving on the Marissa. Chris even had the opportunity to don a semi-dry suit and get wet (but that is a story for another day).

Thanks to Tyler Stalter and Steve Lawson for help with the research, the excellent eye for spotting structure in debris, and the historical photos.