Diesel Submarines for the US Navy? The US Navy invented the nuclear-powered submarine.
The first of these was the USS Nautilus (SSN-571), which was commissioned in 1954 and began sea trials in 1955.
The following year the sub ran a series of test exercises to determine if the anti-submarine warfare tactics used during World War II posed any threat to a sub being powered with this new technology.
The conclusion was that any of the methods used against Japan’s submarines or Nazi Germany’s U-boats would be ineffective against a nuclear sub.
Nuclear-powered boats did not need to surface, could dive deeper, and could clear a search area in record time.
At that time there was no defense against them.
So, it is somewhat counterintuitive that the US Navy would consider investing in the design and construction of smaller and much shorter-ranged diesel submarines today.
Other countries with the resources to do so tried to run away from an all-diesel fleet and followed the US example.
They all have continued to maintain and expand the number of nuclear-powered boats.
An Exclusive Club: No Diesel Submarines for America?
Nuclear-powered submarines have traditionally been seen as a sign of a real superpower naval force.
Countries worldwide that had to rely on diesel-powered boats, which is all but six, have been thought of as second-tier navies.
Being in the “nuclear club” has always been the most visible of military status symbols.
As one might expect, the nation that spends the most on nuclear-powered submarines is the US, and over the following decade, it is projected to dominate this industry with a worldwide share of 44.1 percent. Asia-Pacific follows this at 29.4 per cent and Europe with 22.3 per cent of the global share.
What The Trends Look Like on Submarines
An examination of the projected resources to be expended globally between now and 2034 shows two trends:
The US is going to spend more on nuclear submarines over the next 10 years than the next four countries combined. As it has been for many years, the US maintains a distinct advantage over all other nations in submarine warfare.
The second is that despite the People’s Republic of China (PRC) and Russia being the “pacing threats” that the US is always using as the calculus for determining the size of its own fleet, Australia will spend more on the new trilateral AUKUS submarine program than any of the next three nations included in this rating.
(As previously reported, the Royal Australian Navy (RAN) will first acquire US Navy Virginia SSNs and will subsequently build new fleet of AUKUS-SSNs with assistance from the United Kingdom’s Royal Navy.)
So, why would the US – having been the founding member of the ultra-exclusive nuclear club – consider building diesel subs?
Advantages of Diesel Submarines
There are some very practical reasons for the US Navy to explore designing and acquiring much cheaper diesel-electric submarines actively.
As far back as the 2017-2018 time frame, some in the US Navy had considered the advantages of supplanting its nuclear-powered fleet with these diesel-electric boats. Developments in both the security situation in different regions, as well as the advancements of technology, have played a hand in these deliberations.
Changes in the type and location of conflicts in multiple regions are one factor. A nuclear-powered submarine is not always the best answer when a force is required to operate and fight in littoral waters. It can be too much firepower – and also too much expense for the nation operating it – for a short-range and shallow water fight.
Smaller, quieter, more maneuverable antisubmarine diesel-powered subs (SSKs) are better suited for operations in these regions.
Because of the short distances involved, the high speeds of a nuclear-powered submarine are also not required in shallow waters.
A sub travelling too fast would have inadequate warning to make course corrections.
AIP Diesel Submarines
Another issue is that the increasing capability of Air Independent Propulsion (AIP) systems permits subs to operate as stealthily and without being required to surface in a manner than only nuclear boats were capable of at one time. This means smaller, diesel boats can be employed for special operations missions – where in the past only a nuclear-powered sub could adequately mask its presence to this level.
Pictured is a Kilo-Class Russian Submarine in the English Channel. The image was taken from Royal Navy Wildcat HMA2 Helicopter of 815 Naval Air Squadron. Kilo class is the NATO reporting name for the diesel-electric attack submarine.
A Russian-built, Kilo-class diesel submarine purchased by Iran, is towed by a support vessel in this photograph taken in the central Mediterranean Sea during the week of December 23. The submarine and the support ship arrived at Port Said, Egypt, on Tuesday and were expected to begin transiting the Suez Canal today, Jan. 2, 1996. Ships and aircraft from the U.S. NavyÕs Sixth Fleet are tracking the submarine, which has been making the transit on the surface. This is the third Kilo-class submarine the Iranians have purchased from Moscow. DoD photo
Kilo-class Submarine.
051001-N-0050T-017
San Diego (Oct. 1, 2005) – The Swedish diesel-powered attack submarine HMS Gotland transits through San Diego Harbor during the ÒSea and Air ParadeÓ held as part of Fleet Week San Diego 2005. Fleet Week San Diego is a three-week tribute to Southern California-area military members and their families. U.S. Navy photo by PhotographerÕs Mate 2nd Class Patricia R. Totemeier (RELEASED)
Image: Creative Commons.
Lastly, the diesel submarines could follow the example of the Virginia-class SSNs. As it has been for many other weapon systems for years now, the development of computer systems and data networking technology has finally reached the point where even a system with such demanding design parameters as a submarine can be kitted out with commercial off-the-shelf (COTS) components.
This makes the use of a diesel boat imminently more sensible, cost-effective and allows it to be tailored to the mission. All the more reason to expect to see more of these smaller platforms playing a greater role in undersea warfare in the future.
About the Author:
Reuben F. Johnson is a survivor of the February 2022 Russian invasion of Ukraine and is an Expert on Foreign Military Affairs with the Fundacja im. Kazimierza Pułaskiego in Warsaw. He has been a consultant to the Pentagon, several NATO governments and the Australian government in the fields of defense technology and weapon systems design. Over the past 30 years he has resided in and reported from Russia, Ukraine, Poland, Brazil, the People’s Republic of China and Australia.
