Introduction
One of the projects that has been on my “to-do” list for almost 10 years is to dive the famous “U-Who” or U-869 WW II German Submarine featured in the Shadow Divers book by Robert Kurson. If you haven’t read the book, it is well worth reading even if you aren’t a diver. Kurson is an excellent author and the two protagonists — Richie Kohler and John Chatterton — embark on a 6 year detective journey to discover the true identity of this German submarine located 60+ miles off the coast of New Jersey.
After I started completing more complicated and larger photogrammetry projects, I thought that the U-869 could be within reach and that it would be epic to build a full 3D model of this historic site. I think I could build a high-fidelity model with somewhere between 4-5 dives. Getting those dives would prove to be tough but I did make progress and get one dive on the wreck.
Instead of doing a full trip report and then a full post on the U-869, I will combine them both into this post. For those who don’t really care about the detailed logistics of diving this site, I will front-load the post with information on the diving and the model.
Also, given how famous the U-869 is, I won’t bother providing the details on the wreck or the ship history. There is plenty of information on-line and in the book for any reader who wishes to know more.
Getting to the U-869
If you don’t live within driving distance of the two or three ports that boats leave out of, then the logistics of doing this dive can be even more daunting. Primarily, you need to arrange for rebreather gasses, absorbent, bailout tanks, etc. Luckily for me Rusty Cassway, who operates the excellent R/V Explorer 2.0, was kind enough to provide rebreather and bailout tanks.
The wreck is about 90 miles from the R/V 2.0 home port of Cape May, New Jersey. From the closest point on land, it is about 60 miles offshore. The distance introduces multiple complexities including logistics, medical aid if needed, and potentially rough ocean conditions changing rapidly.
I will cover more in the Logistics section, but we left Cape May around 10pm on Friday night and arrived on-site on Saturday morning around 8am. We went slow overnight to conserve fuel and also ended up scanning a couple new locations on the way. Two divers tied us into the wreck (as is typical in that area) and then we started diving.
The Expedition & Research
The 2026 U-869 Expedition was organized by U-Boat historian Aaron S. Hamilton with the help of Rusty and Erik Petkovic. Aaron is challenging the previous assessments that U-869 met its demise through a circular run torpedo or from a surface attack. He searched through new archival data and conducted an analysis of the wreck site which he first published in his award nominated book Total Undersea War (Seaforth, 2020).
Aaron’s theory is that a combination of factors, unique to Schnorchel-equipped Type IXC/40 U-boats, doomed U-869 through an internal explosion. World-class divers, including Richie Kohler, captured new film footage of unique areas of the wreck site that Aaron and his team of experts in Germany are analyzing to confirm the theory.
I got connected to Aaron through Rusty and we agreed to combine our projects on the same trip. The resulting photogrammetry model, the first model of its kind of U-869, is aiding his team’s research. Aaron’s updated research will be published in the first quarter 2027 edition of US Naval Institute’s Proceedings and may well rewrite U-869’s history.
The Dive
I did my first dive on the wreck with a group of a few other divers. Given that I knew I would only have one, maybe two dives on the wreck, I decided to take the approach of building a “2D” photogrammetry model similar to what I did on the U-2511 in Malin Head, Ireland.
The visibility was decent but probably limited to 20 feet or so which means you definitely couldn’t see the length of the wreck. There was also a lot of plankton and other stuff in the water which made photography challenging. The downline was tied into the wreck right in the middle of the explosion area amidships. I went to the bow first zig-zagging across the top of the structure and then turned and shot more photos as I went aft. When I got to the explosion area, I tried to shoot more photos in and around the area realizing that it would be needed to tie together the model.
Below is a 2 minute video (I run a GoPro on top of my camera housing as backup) of me finishing up the bow section, crossing over the middle breakdown section, and then starting to cover the stern section.
Since the visibility wasn’t great and it was dark, I knew I would need a lot of photos to stitch everything together.
I then went to the stern, turned around, and headed back towards amidships trying to ensure I got all the photos I needed. When I got to the explosion area, I had one part of the project left: the conning tower. I went out and around the conning tower which sits next to the port side of the ship, trying to capture enough photos to stitch together the entire model.
I spent about 25 minutes on the wreck and about 65-70 minutes on decompression in a relatively strong current. Since they tie into the wreck and don’t do drift deco, the current can definitely be felt.
Given my jet lag and the effort on the first dive, I elected to sit out the second dive. It was definitely the safer decision but it did mean that I did not have a chance to take the extra photos that I wanted. There was incoming weather and we couldn’t stay the night to dive more the next day. We left the site around 6pm and went at a higher speed and arrived back at Cape May about midnight — 26 hours after our departure.
The Photogrammetry Model
This one was definitely a challenge. I had only one dive to cover an entire submarine that has a large breakdown from an explosion in the middle of the ship. The complexity of the third dimension definitely complicates it when the visibility is low and the amount of natural light is almost zero.
I took about 800 photos. Most of them aligned; however, the conning tower would not align with the main wreck site. I tried quite a few different methods to get them to align and nothing worked. I ended up creating two models and then overlaying them in Photoshop. Therefore, the dimensions of the conning tower might be slightly off but should be very close since I was able to visually line up the models based on some common points.
I also post-processed the photos to reduce the highlights and to get better color matching. I’ve included multiple versions of the model below, including one that has an overlay of the deck plan. It is, obviously, primarily a two-dimensional model but it does give a good sense of what the current wreck looks like.
Original Model
Below is a screen capture of the original model produced without any overlay. The collapsed section in the center shows just how destructive the explosion was. Stern is on the left, bow on the right, conning tower in the middle on the top.
Site Plan
This is the same model with the major compartments and features labeled — stern to bow, including the torpedo rooms, control room, conning tower, and crew quarters. It gives a clearer sense of scale and helps identify what you’re looking at when it’s not superimposed on a jumble of collapsed hull.
Blueprint Comparison
For reference, here’s the original builder’s plan for a Type IXC/40 — the same class of boat U-869 was. Compare it to the overlay below to see how well 80+ years underwater has (or hasn’t) obscured the original layout.
Here’s that same builder’s plan overlaid directly on the wreck model. The alignment is remarkable in the intact sections — bow and stern still trace the original lines almost exactly. In the middle, though, the plan and the wreck part ways entirely, which tells you everything about how violent that explosion was.
What Sank the U-869?
One of the main reasons for this dive was to look for evidence of how U-869 actually went down. The red arrows above mark debris that’s been thrown outward from the center of the wreck — consistent with an internal explosion rather than a collision or depth-charge damage from outside. It’s not conclusive on its own, but it’s a piece of the puzzle.
Close Ups
Below are some close-up screenshots of the high-definition model. Note that these do not include the conning tower, which had to be reconstructed separately in post-production.
Logistics
For those who might be considering the trip and coming from long distances (i.e., not realistic to drive with all of your own equipment, bailout tanks, sofnolime, etc.), here is what my itinerary looked like. I won’t go into the normal excruciating detail on a regular trip report but this will act as a good guide.
- Day 1 : Thursday, July 30th
- Fly LAX -> PHL
- Stay at the PHL Airport Marriott
- Tip: Get a luggage cart, gather luggage, walk to the Marriott. Requires going up and down a few elevators, but it is possible
- Day 2 : Friday, July 31st
- Leave the luggage at the hotel. Walk across the street to Avis Rentals and get the car. Drive around the outer airport loop and pickup luggage at the Marriott.
- Drive from PHL to Cape May (~ 2 hours)
- Assemble rebreather, camera, sort gear, etc. and store on the boat
- Dinner at Rusty’s house with other divers, board the boat at 10pm and transit
- Day 3 : Saturday, August 1st
- Arrive on-site
- Conduct dives ending at 6pm
- Transit back arriving at about midnight. I left all my stuff on the boat.
- Day 4 : Sunday, August 2nd
- Unload all the gear, grab some breakfast
- Clean and pack up all gear for the trip home
- Drive Cape May to PHL Airport Marriott
- Drop the luggage at the Marriott, return the car, walk back across the street to the hotel
- Get a luggage cart for going to the terminal tomorrow
- Day 5 : Monday, August 3rd
- Take the luggage cart to check-in for the flight
- Fly PHL -> LAX
- Drive Home
It was definitely a long trip for a single dive, but worth it.
I had a lot of fun on the trip and met some really good guys. Rusty and the Explorer 2.0 are both great. Rusty and his wife welcomed me (and others) into their house. It was truly an amazing trip and I couldn’t imagine diving the wreck with anybody else. We had a lot of fun and laughs on board along with some serious diving and exploration. Below are some “B Roll” photos:
Also on the trip were the following people: Rusty Cassway, Aaron Hamilton, Erik Petkovic, Andrew Nagle, Mike Dudas, Richie Kohler, Jeff Goodreau, Fred Engle, Ben Primost, Mike Hopkins, Casey Walentowicz, and me.
Next Up
If I get a chance, I’d like to go back next year and spend 3-4 more dives on the wreck and finish up the photogrammetry model. It is, obviously, a very historic wreck and is showing signs of age. Many areas are collapsing and I want to preserve the history.
Thanks To…
This is a long list but I will try to keep it short.
- My wife for keeping the home-front going while I was gone
- Rusty Cassway – I really can’t say enough about the hospitality I received from Rusty and his wife. I can honestly say that this trip would not have happened without his help.
- Fellow Divers – I appreciate you welcoming me into your “inner circle” and supporting my project. It was truly a “trip of a lifetime” that hopefully I will get a chance to repeat!
- Aaron – Thanks for the collaboration! I’m looking forward to the result of your project getting published!
