Shadow Divers: Much More Than a Thriller

July 23, 2021

Content warning: book spoilers, death.

One day, I was looking for book recommendations and came across a Reddit post titled “Have you even read a book that was so good that you felt grateful for your ability to read?”. After finishing Shadow Divers by Robert Kurson, I remembered this question and was overwhelmed with appreciation: for my ability to read, for the divers’ discovery of the lost U-boat, for the two divers’ dedication to the U-boat, for the author’s eloquent chronicle of their 6-year journeys.

To label Shadow Divers a thriller would almost do the book injustice, as it’s much more than that. To me, more than shipwreck diving, this book is about the human life and death.

“Risked Everything”

Initially, I glanced over at the subtitle “The True Adventure of Two Americans Who Risked Everything to Solve…”, because, surely many people risk everything to accomplish their goals. After finishing the book, I realize that these two divers truly risked everything that is important to a human being: time, money, life, relationships.

Time: Diving is an activity thats a lot of time.

  • It takes time to prepare each diving trip. Even when a trip is scheduled, it could be canceled due to weather.
  • Before doing the actual dive, it takes time to inspect and put on all your gear - there’s no room for mistake in this step.
  • It takes the divers 6 hours to get to the wreck site. They need at least the same amount of time to get back to shore.
  • Decompression takes time and cannot be skipped. Each time the book says “the divers ascended to the Seeker”, the divers would have done their needed decompression, which could take hours.
  • Diving has seasons. This is mentioned in the book and is why the identification of the U-boat ultimately took 6 years.

Money: Shipwreck diving, like other extreme sports, cost a lot of money. I don’t think any of the divers in the book were sponsored to go on their trips, so everything had to come out of their own pockets.

  • They need to pay for charter boats for each trip.
  • They need to pay for their oxygen tanks for each trip.
  • Diving in the cold requires more equipment than warm-water diving, such as dry suit, proper gloves, cold water regulator, etc.

Risks: Scuba diving carries a significant amount of risk due to the nature of the activity. Fatalities happen, and the book covers the risks quite well. So not only were the divers paying with their time and money, they also played with death.

Given the tremendous dedication these men gave to identify the U-boat, it is no surprise that their personal relationships at home suffered. Yet the divers kept pursuing their goal, or at least Chatterton did - he is the one who first reached the wreck and is also the one who ended up pulling out the box from the electric motor room that finally gave the U-boat its name.

The Human Life

Everything that the divers did in this book surrounds the human life (and death). John Chatterton talked about his reasons for wreck diving:

To Chatterton, there always seemed to be opportunity on a shipwreck, even the simple wrecks: the opportunity to confront the problems really worth solving, and this meant everything to him, this was the act that made his life feel worthwhile. He started to tell colleagues that wreck diving had a lot to do with finding out about yourself.

After discovering human remains in the wreck, the divers resolved to identify the U-boat and give closure to the fallen crew’s families. They also wondered about the crew’s lives inside the U-boat and even about their last moments.

During the 6-year journey, friendships were forged and lives were lost. The book concludes after Chatterton finds the identifying tag, and I was very happy to find both Chatterton and Kohler still living today. They are also still actively diving!


Before reading, I had flipped through the book to know that it is mainly about the efforts of two divers. I was surprised to find out that they had ill feelings for each other at first, with Kohler not even being on the initial discovery trip.

As I read, I kept waiting for the moment that defined their friendship, but it never came. It simply developed over time, and there was no one moment. Chatterton and Kohler’s friendship forged over time, over the many trips they took, over the ups and downs they endured.

When describing the family issues that the men had at home, this happened:

In late 1995, Kohler received the same phone call he had placed two years earlier.

I had to re-read this sentence a few times, but I thought it is a poetic way to describe the similar issues that both men faced at different times.

Their forged friendship is manifested towards the end of the book, when Chatterton faced a wall between himself and the U-boat’s identity. Kohler had taken a break from diving. Only after the two started diving again did they make any meaningful progress. And it was with Kohler’s help that Chatterton was able to finally pull the identifying box from the electric motor room. Without each other, the U-boat would likely have taken a lot longer to identify.


Before he could identify the U-boat, Chatterton had a breakthrough year by discovering four other shipwrecks.

In the course of a year, Chatterton had discovered and/or identified four historic shipwrecks. Some began to call him the greatest wreck diver in the world. He sank further into despair.

This reminded me of Messier objects, a set of 110 astronomical objects catalogued by the French astronomer Charles Messie1. Messier wanted to find comets, so he looked into the dark sky. Instead, he found galaxies. Lots and lots of galaxies (and clusters and nebulae). In fact, he found the Andromeda Galaxy, also known as M31, and the bright Orion Nebula, M42.


It’s refreshing to find grit being a recurring theme, having read about it being a more accurate indicator of future success in children than IQ. Here is one of Chatterton’s life principles:

- The worst possible decision is to give up.

There are numerous examples of Chatterton’s grit throughout the book. Here is a paragraph about almost giving up:

In his darkest moments, Chatterton brushed cheeks with the idea of quitting. He imagined a time when he could run out for pizza or take his car for a spin without seeing the U-Who’s crushed control room before him, a time when he longer wondered if he was who he hoped he was. The fantasy always felt good for a minute, but it always ended with Chatterton thinking, “When things are easy a person doesn’t really learn about himself. It’s what a person does at the moment of his greatest struggle that shows him who he really is. Some people never get that moment. The U-Who is my moment. What I do now is what I am.”

Thanks to the pair’s relentless tenacity, a few of the living families of the fallen crew were able to learn the truth about the U-869. If the identification came a decade later, those family members may no longer be living.


All, in all, this book blew me away. I have done shipwreck diving only once in warm water, but it allowed me to empathize with the diving trips described in the book. Halfway through the book, I had found out that Chatterton and Kohler are alive today, so I proceeded to read the rest in peace. Chatterton’s close calls at the very end caught me by surprise, and when I read that he pulled out his regulator, I found myself struggling for air as well, albeit on the couch. I took huge breaths in and out until he reached stage bottle. Phew.

TL;DR This is a great book. Go read it now!