Book Notes | In the Waves by Rachel Lance

Rachel Lance’s In the Waves: My Quest to Solve the Mystery of a Civil War Submarine investigates what happened to the Confederate submarine H. L. Hunley after its historic attack on the USS Housatonic.

I came across her book in a Cal Newport blog post where he mentioned purchasing it. The subject was complex and completely new to me, so I decided to read it and write down what I learnt. [Notes aim to respect the author’s work and avoid revealing too much of the book.]

History

On 17 February 1864, the Confederate submarine H. L. Hunley attacked the Union ship USS Housatonic outside Charleston harbour using a spar torpedo.

The explosion sank the ship, making the Hunley the first submarine to destroy an enemy vessel in combat. However, the submarine disappeared shortly afterwards. Even after the Hunley was found and raised from the seabed in 2000, why the crew failed to return remained a mystery.

Lance first encountered the case while working on blast injury modelling during her PhD in biomedical engineering at Duke University. (She wrote about this here.)

Lance also explores the broader technological context of the Civil War. Both the Union and the Confederacy experimented with new naval technologies, while the Confederacy searched for ways to break the Union blockade of Charleston.

From investigation to reconstruction

Lance explains shockwaves and the physics of underwater explosions before combining archival evidence, engineering knowledge and modern experiments.

Finding somewhere to conduct her explosive tests proved difficult. She described the search for a test site as “an exercise in humiliation”. She quoted George Dixon, the Hunley’s commander, who wrote shortly before the final mission: “And I shall keep trying until I do something.”

Lance adopted the sentence as a mantra. While I would not adopt it myself, it reflects how difficult work can involve uncertainty, criticism, humiliation and delayed proof.

What else I learnt

This was a challenging book for me because it was completely different from what I usually read. I learnt about the Civil War, blast trauma and the development of submarines and torpedoes.

The book showed me how scientific research unfolds: forming a question, planning experiments, finding collaborators and combining evidence. I admired Lance’s discipline, rigour and persistence.

Why underwater explosions are so powerful

A torpedo explosion sends a strong pressure wave through the water. Because water is dense and difficult to compress, it carries that pressure efficiently into nearby structures.

The explosion also produces a large gas bubble that expands and collapses. If it forms beneath a ship, it can lift part of the hull and then leave it unevenly supported.

If the bow and stern remain supported while the middle drops, the hull can bend sharply enough to crack its frame or keel.

Why battleships became obsolete

Through reading about torpedoes, I learnt that battleships are now obsolete. Battleships were designed to destroy enemy ships with large guns while using heavy armour to survive return fire. But aircraft changed things. Aircraft carriers could now launch planes to scout and attack ships hundreds of kilometres away.

The problem then shifted to how to control a larger area through early threat detection and striking from farther away.

Personal reflections

I also learnt that wartime pressure can accelerate technological experimentation and deployment.

Research into blast injury biomechanics may help save lives, but new weapons can also create unintended “signature” injury types.

Will we learn the right lessons from history?