Every so often, we open up our forum to other interested parties, thereby providing collectors, historians and digital tacticians the opportunity to step up on our soap box to voice their opinion on matters of great importance. Recently, we were contacted by Casey Heigl, a well-informed maritime authority, who wanted to share his thoughts on the silent service. What follows are his ruminations on the design and construction of a submarine.

The manufacturing of a submarine is a highly complex endeavor, utilizing both automated and manual processes. In fact, submarines are among the most labor-intensive machines ever built. From the design phase until the time it’s put into service, submarine construction can take up to twenty years, depending on the size of the labor force and the capabilities of the shipyard or yards in charge of building them.

Typically, however, the time between a new submarine model’s initial design work, to laying the keel, to commissioning for actual use is closer to 13 years. Submarines with an already existing class would take much less time to build.

Submarines are known for doing most of their travel under the water’s surface, but they can also travel on the surface like a boat. Before the invention of nuclear submarines, diesel engines were used for travel on the surface and electric motors powered by batteries were used for propelling the vessel below the water’s surface.

Electric batteries have a limited lifetime, though, so even the most advanced early submarines could only travel for a few days underwater and at very limited speed. At full speed, their batteries would be exhausted within hours. Nuclear powered submarines, however, allow the vessels to stay underwater and travel at fast speeds for several months.

Quality Assurance

Before construction even begins, the materials used to build various submarine components are closely inspected for any potential structural flaws. When a new design for a nuclear submarine is initiated, a scale model is built so that it’s easier to identify any apparent flaws and make any necessary improvements. Scale drawings are made, and then expanded into larger paper patterns to allow small details to be examined closely.

When the steel plates that are used to form the hull are cut and rolled, they’re closely inspected to ensure all dimensions are accurate to within a sixteenth of an inch. Smaller parts often need to be even more accurate—sometimes to within even one ten-thousandth of an inch or less. When completed, pipes around the submarine are filled with helium and inspected to check for leaks. Every instrument on board is thoroughly tested and examined to ensure it is in proper working condition.

Materials Used in Submarine Construction

The primary material used for building a submarine is steel. The inner and outer hulls, as well as the inner workings of the vessel, all use steel. Ballast tanks are located between the inner and outer hulls, which take in and expel water to make the submarine sink and rise.

In addition to steel, various other metals, including aluminum, brass, and copper, are used on other parts of the vessel. Non-metals, including glass and plastic, are used in the manufacturing of thousands of other components. The onboard electronic equipment is comprised of semiconductors like germanium and silicon. Cyanoacrylate glue and other adhesives are also implemented to secure various materials found onboard.

The Manufacturing of the Hull

Scaffolding is erected during the manufacturing process so that accessibility remains unencumbered. Thick steel plates are received from steel manufacturers and are cut to the proper size using acetylene torches. The cut plates are then inserted between gigantic metal rollers that are set up with one roller resting on two others, which creates a huge amount of pressure. As the steel plates move between the rollers, they’re bent into a curved shape.

The curved steel plates are then placed on a wooden template outlining the hull’s shape. The plates are then welded together to form an individual section of the hull. The completed section is hoisted by a crane and moved next to its adjoining section. The two completed sections are then welded together. This process continues several times, eventually creating an inner and outer hull.

Steel ribs separate the two hulls and allow space for ballast tanks that control the submarine’s depth. The outer hull extends only as far as the sides and bottom of the inner hull. This allows the vessel to remain upright.

More steel plates are welded into the inner hull to divide the submarine into watertight compartments. Steel bulkheads and decks are then welded into place. Exterior welding seams are eventually polished to make them smooth for painting and provide a streamlined surface that reduces friction during travel.

Completing the Exterior

External components, including propellers and rudders, are manufactured using a variety of metalworking techniques. One integral method used in the creation of several metal components is known as sand casting. Sand casting involves making a plastic or wooden model of the individual part being built.

The model of the part is then surrounded by sand, which is tightly packed in a mold. The two halves of the mold are then separated, and the model is removed. The shape of the part being created remains in the hardened sand as a cavity. Finally, liquid metal is poured into the cavity which, when cooled, results in the completed desired part.

Scaffolding around the hull allows workers to reach any part of it. External components are welded to the hull. Certain components, however, such as sonar equipment, are covered in smooth sheets of steel when they are attached to the hull, so there’s a reduction of friction during travel.

Completing the Interior

Larger equipment is generally placed into the inner hull while it is in the process of being built. Smaller equipment, however, is only brought into the inner hull after completion. The submarine is usually launched before a great deal of the interior equipment is even installed.

Following the launching ceremony, the vessel is towed into a special dock called a fitting-out dock, where additional work on the interior structures continues. Important components, such as engines, periscopes, snorkels, and electronic equipment are then installed. Equipment designed for the comforts of the crew, such as air conditioning, refrigerators, electric cooking stoves, and washing machines are also fitted at this time.

On nuclear submarines, the nuclear reactor begins operating at this time, and the submarine begins its sea trials. The crew is trained, weapons are tested and launched, and the submarine is commissioned in an official ceremony which alters its designation. The submarine is then given a shakedown cruise before it is entered into active service. Tests to the maneuverability and speed of the submarine are meant to indicate how the submarine would operate in simulated wartime conditions.

Looking to the Future

Submarines are expected to hold their place as a crucial component of Navy defense systems for years to come. Newer designs could showcase new ways of improving the depth and speed capabilities of submarines. Future research will likely lead to a submarine’s increased ability to detect enemy ships while maintaining its own ability to remain undetected.

Image Links

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