There is an emerging subculture where amateur enthusiasts are constructing homemade submarines in their backyards and garages. However, this pursuit might be fueled by something more unsettling than just a quirky interest in engineering or a fascination with the ocean depths.

A recent book proposes that the peculiar hobby of descending hundreds of meters in DIY submersibles could, for some individuals, be tied to unusual sexual urges and Freudian fantasies of reverting to a ‘womb-like’ state—urges that, in extreme instances, intersect with violence.

In Submersed: Wonder, Obsession and Murder in the World of Amateur Submarines, author Matthew Gavin Frank explores what genuinely attracts certain individuals—predominantly men who describe themselves as ‘loners’—into the depths.

The answers, he suggests, might have less to do with adventure and more to do with power, isolation and escape.

Central to Frank’s exploration is the concept of claustrophilia – a niche phenomenon that, according to Psychology Today, can manifest as a sexual fetish or ‘extreme form of bondage’.

Claustrophilia, the arousal or comfort from being trapped, is the opposite of claustrophobia, which is the fear of small spaces. 

People with the condition describe feeling safe, euphoric or emotionally detached when confined in tight spaces such as boxes, cages or caskets. 

For some, it’s incorporated into sexual practices, where the loss of physical freedom intensifies feelings of helplessness, control or submission.

Frank suggests that submarines can act as a ‘steel spheroid’ version of this fantasy – an airtight, pressurized capsule sealed off from the world.

Psychologists also link claustrophilia to ‘regression fantasies’, the desire to return to a pre-birth state, with the enclosed space replicating the maternal womb.

In this framework, the submarine becomes a symbolic, suspended refuge in which the self disappears or is reborn.

This mental retreat can be intensified by the physical effects of deep-sea diving, Frank writes.

According to experts cited in his book, breathing compressed air under water can lead to nitrogen narcosis, a condition that alters brain function in ways similar to alcohol or drugs.

Diving medicine expert Dr David Sawatzky says in Submersed that symptoms can include euphoria, impaired judgment and hallucinations. 

For those already drawn to confinement, the sensation can be addictive. 

Plus, Frank writes, ‘Many have seen the sub as a safe haven from surface mores and government strictures.’

He says it’s ‘a place of ultimate control, where they can exact a brief lordship over their womb-like world – a womb created by them, for them, that gives back by incubating only them.

‘In here, they don’t have to share their resources. In here, what they say and do goes.’ 

More disturbingly, experts believe that this urge to escape the self mirrors ‘regenerative dissociation’, a pattern observed in certain acts of violence, including fantasy-driven homicide.

Psychologist Andrew K. Moskowitz has found links between long-term dissociation and extreme behavior.

Violence committed at depth can feel distant and unreal, disconnected from everyday consequences, Frank writes. The submarine becomes a space where someone can act on their darkest urges, free from scrutiny from those on the surface.

When that private space is breached by another person, the results can be catastrophic, according to Frank.

The most notorious case involves Swedish journalist Kim Wall and Danish inventor Peter Madsen, which is a through line for Submersed.

In August 2017, Wall, 30, boarded Madsen’s famed UC3 Nautilus, then the world’s largest homemade sub, to interview him.

Madsen, then 46, returned alone. 

First, he would claim that Wall had died in an accident and he had buried her at sea. However, days later, Wall’s dismembered torso washed up on a beach, and other remains were found in Køge Bay.

Madsen, who had no history of violence, was accused of torture, having ‘sexual relations other than intercourse of a particularly dangerous nature’, according to court records, and murder. Stab wounds were discovered in and around her genitals. He was sentenced to life in prison.

News of his crimes shocked the world but, as Frank argues, a passion for submarines can ruin a person for the surface’, and sometimes the compulsion to sink to great depths can ‘dovetail with darker, more threatening traits’.

According to Frank, Madsen fits the psychological profile he explores in Submersed.

Raised in an abusive home and abandoned by his mother at a young age, he later immersed himself in bondage and discipline, dominance and submission, sadism and masochism practices, and private fetish parties.

In 2007, Madsen blogged that he wanted to build submarines to make himself ‘ungovernable and uncontrollable’.

He described the sub as a place of comfort ‘away from the judgmental eyes of the surface dwellers’.

During the trial, Madsen repeatedly compared himself to the Terminator, ‘hinting at his latent desire to become part of the machines he built’, Frank writes.

Madsen believed he and Nautilus ‘shared a brain and a vision.’

He never admitted to murdering Wall but confessed to dismembering her body while in a state of ‘suicidal psychosis’.

The night before the fatal voyage, Madsen searched the internet for information on ‘executions and dismemberment’, ‘beheading’, ‘girl’ and ‘agony’, testimony showed.

Frank also infiltrated what he calls the ‘eccentric micro-community of DIY submersible enthusiasts’, largely comprised of white men between the ages of 20 and 70.

Many, he writes, are self-described ‘misfits’ living off the grid, are self-taught in the art of sub building, and ‘have a distrust of government ranging from healthy to conspiratorial’.

Most are also blasé about the threat of possible death inherent to their hobby.

In Alaska, Frank met Albrecht Jotten, a German-born builder, who dives in Kachemak Bay and believes that he will one day be considered among history’s greatest minds. Jotten, who lives in a one-bedroom cabin in the woods of Homer, confessed to Frank – after asking the author to confirm he was Jewish – his belief that Adolf Hitler was the greatest genius who ever lived.

Madsen also had a preoccupation with Hitler, role-playing as a Nazi and pretending his sub was a German U-boat.

Frank has tracked down one of the few women in the field, Shanee Stopnitzky, who says she has spent more than a year cumulatively under water.

Stopnitzky has aspirations to build an under water home, where she’d live full-time, telling Frank she never felt quite at home on the surface.

Submersed was released on June 3, two weeks before the second anniversary of the Titan submersible disaster that killed five people during a dive to the Titanic wreck.

OceanGate CEO Stockton Rush was piloting the vessel when it imploded. Frank draws parallels between Rush and Madsen: both obsessive, ego-driven and dangerously dissociated from risk below the surface.

Karl Stanley, an expert in commercial submersibles, tells Frank he believed Rush was suicidal and hellbent on writing himself into the mythology of the world’s most infamous shipwreck, even if it meant taking four other lives with him.

Twelve days after the disaster, Stanley messaged Frank on WhatsApp, offering a grim appraisal: Rush had known exactly what was going to happen – and designed the plunge as a one-way trip to cement his legacy.

‘He was, in fact, a good engineer,’ Stanley says. ‘He set a new standard for going out with a bang.’

In 2019, Stanley joined Rush for a test dive in the Titan in the Bahamas, where they descended to a record-breaking, Titanic-level depth of 12,336 feet.

The following day, Stanley warned Rush that the gunshot-like sounds heard every few minutes during the dive were the sub’s hull breaking under the pressure. He concluded that Titan would meet with catastrophe if changes weren’t made. 

On June 18, 2023, Rush, 61, and four passengers – British billionaire Hamish Harding, 58, businessman Shahzada Dawood,48, his son Suleman Dawood, 19, and French explorer Paul-Henri Nargeolet, 77 – descended thousands of feet through the dark North Atlantic to catch a glimpse of the Titanic.

One hour and 45 minutes into their journey, the sub lost contact.

For four days, the world held its breath as a dramatic international search and rescue mission unfolded in the waters several hundred miles southeast of Newfoundland.

Then, on June 22, the US Coast Guard confirmed the Titan imploded 1,600 feet from the Titanic’s bow and killed all five on board.

Initially hailed as a pioneer by OceanGate colleagues, Rush was later exposed as having ignored glaring safety warnings – and advice that a disaster of this magnitude was predictable.

‘He knew that eventually it was going to end like this and he wasn’t going to be held accountable,’ Stanley told a panel investigating the disaster.

‘But he was going to be the most famous of all his famous relatives,’ he said.

Rush claimed descent from Declaration of Independence signers Richard Stockton and Benjamin Rush, and was related by marriage to Isidor and Ida Straus, who died on the Titanic.

Submersed: Wonder, Obsession, and Murder In The World of Amateur Submarines, by Matthew Gavin Frank (Pantheon), is available now.