Everything else on this site has been about diving. This is the first proper post for Build — the part where I’m eventually going to try to build a submarine. Before I get anywhere near a workshop, though, I wanted to actually understand what a submarine is and how the whole idea got started.
What a submarine actually does
A submarine floats or sinks on purpose, using ballast tanks. When the tanks are filled with air, the submarine is lighter than the water it’s pushing out of the way, so it floats — that’s called positive buoyancy. To dive, the crew lets water flood into the ballast tanks and vents the air out, making the submarine heavier than the water around it, so it sinks — negative buoyancy. To hold a steady depth without sinking further or floating back up, they balance the air and water until the submarine weighs exactly the same as the water it’s displacing. That’s neutral buoyancy, and it’s the whole trick.
The first submarine ever used in an attack
The very first submarine used in combat was Turtle, built in 1775 by an American named David Bushnell. It was a small, egg-shaped, one-person craft, moved by hand-cranked propellers, with its own ballast tanks and air pipes. On 7 September 1776, a soldier called Ezra Lee actually piloted Turtle underneath a British warship, HMS Eagle, in New York Harbour, trying to attach a bomb to its hull. It didn’t work — he couldn’t get the bomb to attach — but it was still the first submarine attack in history, which is a fairly big deal for something built in someone’s workshop nearly 250 years ago.
The first “modern” submarine
In 1800, the American inventor Robert Fulton designed a submarine called Nautilus for the French government. It was made entirely of metal, had adjustable diving planes to control depth more precisely, two different ways of moving through the water, and a compressed-air system that let the crew stay underwater for around four hours. A lot of these ideas — diving planes, proper propulsion, air supply — are still part of how submarines work today, which is why people often call it the first genuinely modern submarine design.
The real breakthrough
The person usually credited with the modern submarine is an Irish inventor, John Philip Holland. He built a model in 1876, a full-size version in 1878, and several more after that, before his Holland Type VI design in 1896 finally got it right: an internal combustion engine to power the submarine on the surface, and an electric battery to power it underwater, where an engine that needs air to burn fuel simply can’t work. That combination — one engine for the surface, a completely different power source for underwater — became the standard design for decades.
Then it got a lot bigger
Submarines went from experimental inventions to genuinely important weapons extremely quickly. German U-boats in the First World War showed how dangerous submarines could be to ships that never saw them coming, and by the Second World War, submarine warfare was a major part of how the war was fought at sea.
The one that changed everything again
In 1954, the USS Nautilus became the world’s first nuclear-powered submarine. That mattered enormously, because older submarines still needed to surface fairly often to recharge batteries or get air for their engines. A nuclear reactor doesn’t need air to work, so Nautilus could stay submerged for far longer than anything before it. On her first major voyage she travelled more than 1,300 miles completely underwater, and in 1958 she became the first submarine to travel under the polar ice cap.
Why I’m starting here
I’m obviously not building anything nuclear-powered. But almost every early submarine story has the same shape: someone works out how to control buoyancy properly, builds something far too small and slightly terrifying, and either it works or it very much doesn’t. Bushnell’s Turtle was hand-cranked and one person could barely fit inside it. That’s honestly a much more useful starting point for me than a nuclear submarine is — small, simple, and built by someone figuring it out largely for the first time.
The one rule I’ve already set for my own project, from the very first Build post, is that it should be positively buoyant by default. If anything fails, it should float, not sink. Looking at this history, that’s not a new idea at all — it’s basically the first thing every submarine designer since 1775 has had to get right before anything else.
Questions & Answers
How does a submarine actually float and sink?
Using ballast tanks. Filled with air, the submarine is lighter than the water and floats (positive buoyancy). Flooded with water, it’s heavier than the water and sinks (negative buoyancy). Balanced exactly, it holds a steady depth (neutral buoyancy).
What was the first submarine ever used in combat?
Turtle, built by David Bushnell in 1775. It was used in an actual attack on a British warship in New York Harbour on 7 September 1776, though the attack itself failed.
Who is credited with the modern submarine design?
John Philip Holland, whose 1896 Holland Type VI combined an internal combustion engine for surface travel with an electric battery for underwater travel — a combination that became the standard for decades.
What was special about the USS Nautilus?
Launched in 1954, it was the world’s first nuclear-powered submarine, able to stay submerged far longer than older submarines, and in 1958 it became the first submarine to travel under the polar ice cap.
References
- HISTORY.com. 9 Groundbreaking Early Submarines.
- Naval History and Heritage Command. Submarine Development: A Short History.
- Naval Undersea Museum. Ballast and Buoyancy.