Cessna Photogrammetry Model (Mission Beach — 205 fsw)

Introduction

Tyler and I got a lead on a P-38 that was in deep water (325 fsw) off of Point Loma so we decided to go out with Chris & Lora on the Marrisa.

For those types of depths, it is always good to have a couple of divers with you that you know will be there if problems happen. It also helps ensure we have enough bailout gas in the water just in case something goes wrong. I was out diving with Danny Graham and Drew Wilson and we had a crap-load of gear and tanks for the dive.

Below are photos of my gear loaded in the car the afternoon before the dive, Drew prepping his rEvo on the boat, and the explosion of dive gear after cleaning and waiting to be put away:

Between the three of us, we had 11 bailout tanks, three scooters, and two big camera setups along with our rebreathers and other miscellaneous equipment.

The conditions were not great and we spent an hour fighting wind and current trying to get a good sonar return. We couldn’t get a good enough return to warrant making a dive that deep in those conditions (in that dive, even 5 minutes of bottom time will required over an hour of decompression).

The source for the numbers is good and there could be something there but we decided to return another day to investigate further.

We decided to head back north and dive a Cessna off Mission Beach that we had found a few years ago (we were not the first divers to find or dive it). I figured Drew & Danny could dive something new and I could build a photogrammetry model to document it and we would have a relatively easy and fun dive and not go home “empty handed” after hauling all of that gear.

History

This Cessna crashed in September 1976 when it ran out of fuel. It had three people on-board (including the pilot) and, unfortunately, only two of them survived. Tyler had a newspaper article about the accident:

The wreck was discovered in the early 2000s and the location was kept secret. Tyler ended up identifying a blip on the bathymetry data which is when we first dove it in 2021.

Photos

Since Drew was along, we did our usually routine where he took pictures of me taking pictures. They are natural light photos so there is almost no backscatter and it gives a really good perspective. He was kind enough to give me some of the photos which I’ve included below (he calls the bottom photo “Brett vs The Wall of Fish” and is taken of me at the prop area of the wreck.

As you can see, the wreck is COVERED in juvenile rockfish.

After I got the photos for the model, I decided to get a couple pictures of Drew & Danny on the wreck. In one of the photos from Drew above (top left), you can see me taking the photos of Danny near the cockpit / prop. Below are photos of the backseat area, the cockpit, the 6 cylinder engine, and then Drew & Danny on the wreck.

Along with the fish, there is also a lot of rope on the wreck which creates a hazard when taking photos and trying to get a bunch of detailed photos inside the cockpit, etc.

Photogrammetry Model

The wreck is small so the model didn’t require a ton of pictures (about 350 in this case). However, there was a TON of fish on the wreck which results in alignment issues AND also results in a blurry effect on some parts of the model. The way that the texture process works is that it takes a mosaic of the different photos that cover a specific area. Therefore, when you have some photos with fish and some without, the result is a bit blurry. Either way, the model turned out well.

Model Screenshots

Below are some screenshots from the model that show the port side, starboard side, prop, dashboard, etc.

Online Model

Below is a link to the on-line photogrammetry model:

Thanks

• A big thanks to Tyler for his partnership. We do a lot together and I’m confident that we’ll find the P-38.
• Thanks to Danny & Drew. They both drove long distances, prepped a ton of gear, and battled traffic going back home. We didn’t find the P-38 we were looking for but we made the best of it and had a great time.
• Big thanks to Lora & Chris at Marissa Charters. There aren’t many boats I would plan to do a 100m dive from in Southern California in the open ocean. Doing that kind of dive requires a lot of trust in your dive partners but also in the boat and crew and I have complete trust in them.