DIY Submarine Kits: Why They’re Not Worth the Risk

DIY Submarine Kits: Why They're Not Worth the Risk

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We live in the age of DIY. People today are passionate about doing everything themselves, from making skincare products to growing food. For divers, DIY might get a little more complex, but still looks appealing: who wouldn’t want to try DIY submarine kits?

You can find DIY submarine instructions if you search for them online. You may also come across a few optimistic success stories of people who made their own real, working submarines. The appeal of seeing the underwater world in a whole new way is hard to deny. However, DIY submarine kits are a dangerous way to do it. Leave the submarine building to the professionals instead.

How Submarines Work

Submarines take the technology that makes ships float, and use an inverse version to make them sink, too. Most submarines involve an elaborate apparatus — let’s take a look at some of the things that keep them working.

Floating and diving

When a ship floats, it’s because it displaces enough water to equal the weight of the ship. Gravity is pulling the ship toward the bottom of the sea. However, the displaced water has its own force, called buoyant force, and it’s enough to oppose gravity and keep the ship on the surface.

Of course, ships sit on the surface of the water with no hope of diving and coming up again. But a submarine uses a system of trim and ballast tanks, filling them with either water or air to change the water displacement of the vessel. When the submarine floats on the surface of the water, those tanks are full of air. That makes the sub less dense than the water around it. However, as the tanks fill with water, the density goes up, causing the sub to go down.

Submarines further control the direction of the dive using hydroplanes on the stern. These adjust the angle of the dive, by moving water across the stern of the sub.

Another submarine method uses a double hull to adjust its level in the water. The inner hull holds the crew, while the outer hull can be filled with water or air as needed to move the sub to the surface and down again. Submarines carry compressed air on board for when the ballast tanks or outer hull need to be filled with air again.


Once the sub is underwater, how can the crew maneuver it? When it’s reached the ideal depth, the crew levels the hydroplanes to keep it on a steady track at the same depth. They also maintain the same ratio of air and water in the outer hull or tanks. A rudder on the rear of the sub allows for steering right and left. Modern subs may also use secondary propulsion motors that can move them in any direction underwater.

Inside the sub

Just building a machine that can effectively navigate the water both up and down, and around 360 degrees of horizontal directions, is hard enough. But if you want people on your sub, you need to create an environment where they can survive underwater — and that’s even more challenging. As you can see, no DIY submarine kits will be able to provide everything that you need for a successful sub.

First, submarines have to be able to maintain a temperature that’s conducive to human life. Underwater, it can get extremely cold, especially as you go farther below the surface. Electric heaters on a submarine might pull power from the engine, or even from a nuclear reactor. Batteries often serve as a backup source of heat power.

The submarine also needs to have enough fresh water for the crew. This usually involves a method of distilling seawater, since it wouldn’t be practical to carry a large amount of fresh water on board. These distillation methods separate the salt and other particles out of the seawater. In addition to keeping the crew thriving, this freshwater supply also helps keep important electronics on board cooled for optimum performance.

Of course, submarines also need to have enough oxygen to support the crew for as long as they’re on board. As people breathe oxygen in and carbon dioxide out, the submarine needs to replenish the oxygen supply on board.

Submarines can provide oxygen using a few different methods. They can have pressurized tanks of oxygen on board, or use oxygen generators that create oxygen using water. Onboard sensors can tell how much oxygen is in the air, and when more needs to get released.

Types of Submarines

Can a DIY project provide all of these essential features, plus other necessary things like navigation equipment and a power supply? It’s pretty unlikely. However, there are a few different types of submarines. Let’s take a look at what they are to help determine if you can build any of them by hand.

Wet submarine

This kind of submarine functions like an underwater ATV. Unlike most submarines in popular culture, a wet submarine doesn’t keep the people inside it dry. You’ll need to use scuba gear and prepare to get wet in this kind of sub.

You’ll also get exposed to the pressure of the water, so these submarines aren’t useful for deep dives. The diver on a wet sub “rides” the sub, seated as though they were in a kayak. Most of these subs get their power from batteries and use electric motors for propulsion through the water.

Semi-dry submarine

Semi-dry models keep the top part of your body dry, so you have a dry viewing chamber for the underwater world around you. In this small air pocket, you can see and breathe normally so that you won’t need full scuba gear. You’ll just need to protect the lower half of your body, which remains in the water.

Although you won’t need scuba gear, the air inside these subs is compressed, so you have to take care with your ascent to avoid decompression sickness. Most people who are comfortable with scuba diving will find wet and semi-dry subs fairly easy to use, though.

Ambient dry submarine

In an ambient dry sub, you stay completely dry, but you’re in a bubble of air compressed at the same pressure as the water outside. The same rules for ascension in a semi-dry sub apply in an ambient dry sub, too. You’ll need to return to the surface slowly so the compressed air won’t pose a danger as you rise. These subs should be kept close to the surface to keep the diver safe.

One atmosphere submarine

This fully dry type of submarine has an air pressure inside that’s the same as above the water. That’s the kind of sub most people think of when they think of a submarine: one in which the crew can live and work like normal.

The name “one atmosphere” comes from the fact that there’s one atmosphere of air pressure on the surface of the Earth and the same air pressure inside this kind of submarine. These models are more complicated to build, but can hold more people and dive deeper than the other types listed here.

Submarine Uses for Divers

As you can see, there are many parallels between submarines and divers, especially with the wet and semi-dry submarine styles.

These submarines allow divers to explore the world below the water’s surface much more easily. It’s like having an underwater motorcycle! With this type of sub, you have more powerful propulsion than what your own body can provide so that you can move farther and faster.

They can help you get to areas that you might not get to see otherwise. Do they offer a thrill that anyone who’s into scuba technology will understand — who wouldn’t want to play with the coolest underwater toys?

Can You Use Homemade Submarine Kits to Build One?

With all of that in mind, can DIY submarine kits allow divers to build the most simple of submarines, if not the more elaborate types? Unfortunately, the answer is still no. Even very basic submarines require a lot of safety features to work well and protect users.

You might feel confident building a vehicle that works on land, such as a go-kart. But an underwater vehicle requires many more safety features. It needs to be safe to operate in the water and able to stand up to the corrosion of salt water. It needs to have precise controls that allow a user to raise and lower it as needed, safely. Many types also need to be able to offer a source of air, and sometimes air pressure, for the user inside.

While a few accounts of DIY submarines do exist, there’s just no way to guarantee you can safely build one on your own.

What it Takes to Build a Submarine

Taking a look at what it really takes to build a submarine will help you better understand why DIY submarine kits just won’t work. Most submarines get built in shipyards, where the space and necessary materials are abundant. They often begin with a strong hull made of a material like steel.

If it’s a one atmosphere sub, the building process starts with a primary pressure vessel. This vessel provides the space for the crew. Then, an outside shell to provide a layer of protection for the crew gets added to this interior. If it’s not a one atmosphere sub, the building process can start with the exterior.

The hull needs to be carefully welded together, so it’s watertight. Then, builders must add the ballast tanks, engine, steering mechanism, and more to make the sub operable.

Even for the smallest of wet submarines, the steering and ballast methods need to be accurate. If a diver can’t properly navigate in the water, they won’t have any way to avoid possible danger. It’s also critically important that the diver can control the rise of the submarine, to avoid decompression sickness. If something goes wrong, the consequences could be fatal.

The Dangers of DIY Submarine Kits

Diving itself, even without a submarine, carries its fair share of danger. However, using careful practices and good equipment can keep that danger at a minimum. DIY equipment doesn’t provide enough protection from the dangers posed by the water. While DIY submarine kits might sound tempting, they’re just as dangerous as making your own oxygen tank.

Of course, you won’t find any trusted scuba gear retailer selling DIY submarine kits, because of this danger. If you find DIY submarine kits or instructions online, they aren’t coming from a reputable source. That adds to the danger even more — you won’t know if the materials you’re using are of a high enough quality to be safe.

What about the DIY instructions that you find online, and source the materials for yourself? Even though you could buy high-quality materials, quality control is an important part of the submarine process. With no professionals around to check the quality of your work, you’re still putting yourself in needless danger.

Enjoying Submarines Without the Danger

DIY submarine kits are dangerous, no matter how good you are at building things. However, you can use personal submarines for your dives while avoiding the danger by buying or renting high-quality, professionally built subs.

Personal submarines don’t come cheap. You can expect to pay anything from $19,000 up to millions of dollars for your own sub. However, some areas also offer personal sub rentals for divers looking for a new thrill. This option goes much easier on your budget, while also keeping you safe.

Are you ready to try renting one of these cool one-person subs for your next dive expedition? Or are you sticking with your trusty, familiar scuba gear? Let us know in the comments section!

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