Wreck Interior Studies – Part III (HMCS Yukon Stern Corridor)

Background

This is the third in a series of posts about my project to document the interiors of wrecks.

The first post covered the engine room of the Ruby E, the second post is the engine room of the Yukon, and this post will be about the corridor (or path) leading from the stern of wreck into the engine room.

This part of the project had a number of challenges but resulted in what I consider to be a pretty cool view into the interior of wrecks.

The Dive

I spent part of one dive to shoot the photos for the corridor. I started in the engine room to be able to align with photos from a previous dive and then moved towards the stern.

Challenge 1: The most challenging part of this project was getting photos around thin bulkheads between compartments. You essentially need to slowly approach the bulkhead and take pictures which have some part of the photo on the near side of the bulkhead and then find a spot that has something on the far side of the bulkhead in the same frame. It can be very challenging since there is a lot of empty space.

Below are photos of the beginning of the corridor leading from the engine room towards the stern. This is a sequence of six photos but I’ve only included every other photo so there are actually twice as many for this transition to ensure alignment.

There are about 560 photos in the engine room that were taken on Dive 8 of the overall Yukon project and then 826 photos taken in the engine room and through the corridor to the stern on this dive.

Aligning the Photos

The first few attempts I made to build the model didn’t work.

Challenge 2: Getting “true” alignment of photos. The way that the photogrammetry software works is that is has an “affinity” for photos taken during the same dive. This makes sense, but can result in mis-alignments when large structures are modeled.

In this specific case, my first approach to modeling the corridor was to take some pictures inside the engine room to align with the previous model I detailed in the second post and then take pictures on the way to the stern exit. When I built the model of the corridor, the engine pictures aligned but then as I got close to the stern, you can see that they have nothing to align to but themselves and any small errors are compounded over long distances.

The corridor modeled below should NOT slant towards the bottom of the stern.

For my next alignment attempt, I started building a model from the photos I took but I did it from both ends. I started building from the stern photos and from the engine room photos. Below are four screen captures showing the progress from each end.

NOTE: These screen captures are looking from “below” the wreck so that the outside hull doesn’t obscure the corridor.

I would slowly add sets of photos from the stern and work my ways towards the engine room. Eventually, I was able to connect the two in a viable alignment.

Photogrammetry Model

I have screenshots from two versions of the model. The first version is the model without the rest of the Yukon hull (only the engine room and corridor) and the second shows the corridor within the wreck.

Corridor & Engine Room Only

I like this model because it focusses on only the interior of the wreck and I probably like the point cloud view the best because it is “semi-transparent” to show the 3D view of the interior. Below are two views of the sparse cloud. The first is from the engine room in the foreground in the lower right and the stern in the upper left. The second is the opposite view.

Below are some screen captures of the “solid” model.

Corridor Within the Wreck

This view of the model shows the corridor within the context of the overall Yukon model.

First is the sparse (or point) cloud that provide the semi-transparent view.

For the solid model, once again, I had to work some magic to remove the “skin” of the wreck to provide a sense of the interior corridor. Below are a few different views of that view.

Next Up

I’ve been testing out a Insta360 Camera that can show a 360 video as I go through the wreck to give the viewer an immersive feel for what it feels like to navigate through this wreck. Stay tuned….