As a follow-up to the post about the photogrammetry model of the Yukon guns, on the same dive I took a series of photos of the props and rudder (given that it is deeper, I actually took these pictures first).
Interestingly enough, the two features I decided to document for models BOTH turned out to be fake!
From the first time I dove the wreck, I have always found the prop on the Yukon to be very interesting. It has an interesting shape and doesn’t seem to have an actual propeller. Below are a couple pictures (these were taken for building a 3D model and not for their composition):
After doing some research on the guns, I found out that the original prop on the Yukon had also been removed at some point
According to an article in California Diving News
The props look odd because they are not normal propulsion propellers but rather training devices that were used dockside to teach Canadian sailors on proper operation of the ship’s engines while still dockside.California Diving News
I also checked in with Steve Lawson who provided a few more details. He mentioned that:
It’s a giant concrete disk used for training. The disk would spin, creating a load for the engine without providing forward thrust which they didn’t want while tied up to the dock.Email with Steve Lawson
So, essentially, it is the “training wheels” for learning how to operate the ship’s engines. 🙂
The model was relatively straightforward to build.
I built the first model by starting with a few photos and then slowly added additional photos and ensure that they aligned. It resulted in a reasonably good sparse cloud but the dense cloud and textured model didn’t work out well.
Knowing that the photos could align, I then started from scratch on the alignment. They didn’t all align on the first pass but after a quick re-alignment of the photos, I had 184 of the 193 pictures I took aligned.
I then built the dense cloud on High Quality and you can see that the entire structure including the rudder can now be seen. The Depth maps and Dense Cloud took about 45 minutes to process.
And then the final step of creating the textured model:
Below are various screen grabs and a link to the on-line model at Sketchfab.