UB88 Photogrammetry Project – Dive 5 (Forward Section)

Background

It has been a long time since I dove the UB-88 and I had definitely missed it. I think it is one of the coolest wrecks in Southern California.

My previous dive on the UB88 was December 10, 2020 and the visibility was soooo bad at depth that Justin and I couldn’t even find the wreck even though it is a 190-foot long massive tube. We had a winter with big, deep swells here; therefore, dives in mid-channel between the mainland and Catalina weren’t even worth trying.

I was finally able to go back this past week and Drew Wilson and I did a dive on the UB88 and then another dive on an unidentified barge (I’ll detail that dive in another post). The goal was to get pictures of the port and starboard hull forward of the conning tower in order to complete the front half of the photogrammetry model.

The starting point of the model (sparse cloud) before this dive is shown below. You can clearly see the missing hull sections on the starboard and port sides.

Sparse cloud

The Dive

It had been about a month since I was in the water but the dive went well. Drew and I work well as a team. The visibility was reasonably good but had a bit of a “haze” over the wreck, especially when the bright video lights were turned on and reflected back particles in the water.

While I took pictures of the front hull, Drew scootered around and took pictures of me taking pictures. 🙂

Drew’s picture of me taking pictures on the UB-88

We had a little less than 20 minutes on the wreck and then began our decompression schedule. Interestingly enough, Drew had more than 10 minutes extra decompression compared to me. During the dive recap, we chalked that up to a combination of the Helium penalty (I had 12/42 and Drew had 10/50) and Gradient Factors (me at 50/80 and Drew at 30/70).

Photogrammetry Model

The results turned out relatively well.

I need to figure out a scalable method of dealing with different water colors and different lights but the model itself is pretty good at this point. You can see the brighter, “white” lights that I was using on the front torpedo tubes on a dive in blue water vs. the “warmer” lights I used on the hull in green water.

UB-88 Forward Section

Here are some static screenshots:

Next Steps

I previously attempted to create a model of the stern torpedo tubes that was semi-successful. I probably have 3-4 more dives to complete the entire model. I think I can get most of both sides of the hull to the stern of the conning tower in 1-2 dives and then I’ll need to figure out a strategy for the stern torpedo tube and the ghost nets.

Stay tuned…

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