Unknown / Unidentified Object (Pt Loma — 225 fsw)


I’ve got a few posts about local dives that have been on hold for a while as I was preparing for and going on my trip to Bikini Atoll (more posts on that coming up)!

This one is about something that is very weird that we dove as the first dive on the morning of June 7, 2023. We haven’t been able to figure out what it is (yet). Maybe some sharp-eyed reader will have some ideas. This showed up in a side scan while we were actually out looking at other targets so we decided to dive it. The conditions were very nice that day, especially in deep water.

The Dive

Lauren and I dropped down on the target and didn’t see it at first but I saw fish so I followed them and found the wreck. There were a TON of rock fish on the wreck. Given the holes in the structure, at first I thought it was something for an airplane but quickly realized it was more extensive and the beams were too thick. I then thought it might be an anchor of some sort when I saw some curved sections but then realized it was too big and that there were more than one of the curved sections.

Since I really didn’t know what the object was, I decided to snap enough photos to get at least a rough photogrammetry model for analysis post-dive. The structure itself is probably 30-40 feet long with multiple “arms” jutting out from the main beam.


Below are some photos of the object that we found. It looks somewhat like a crane arm. It has holes in the structure which indicates that it was trying to limit weight.

The first photo is of Lauren at the end of the dive. It is a natural light photo which, at that depth, requires an open f-stop, a slow shutter speed, and a really high ISO so there is some grain in the picture but it gives a good sense of the fish and the “tip” of the structure.

Below is a montage of photos from various parts of the structure. It will be a lot more obvious in the model shown below.

Photogrammetry Model

This is a prototypical example where a photogrammetry helps to “see the bigger picture” since all the still photos look like a jangle of beams. The screenshots and the link to the model below show the whole structure and provide context.

The online 3D model is posted at the link below:

Online 3D Model of “Girders”

Next Steps

We don’t have any intention of diving this site again. If somebody has an idea of what this structure is, please reach out.

3 thoughts on “Unknown / Unidentified Object (Pt Loma — 225 fsw)

  1. Just a guess here, but it looks like some type of jig, scaffold or something similar that would be used to support something with a rounded shape, such as a plane or boat hull. The holes aren’t designed for lightening as with aircraft, they are all small, the same diameter and placed at the regular intervals. They could have been used for bolts/points of attachment.

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