NavalWarfare

CIWS on board USS Gravely shoots down cruise missile fired by Houthis

According to CNN a cruise missile launched by Houthis rebels into the Red Sea on the night of Jan. 30, 2024 came within a nautical mile of the Arleigh Burke-class guided-missile destroyer USS Gravely (DDG 107), marking the closest such attack on a US warship to date. The missile was ultimately destroyed by the ship’s Close-In Weapon System (CIWS), marking the first time this defensive system has seen combat action on a warship.

USS Gravely uses CIWS against threat posed by Houthis

As Alert 5 says, previously, Houthis missile attacks against vessels in the Red Sea had been intercepted at a distance of eight miles or more.

This incident, however, highlights the evolving capabilities and potential threat posed by the rebels, raising concerns about the safety of maritime traffic in the crucial waterway. The close call also comes just days after three US service members were killed in a drone attack by Iran-backed militants at a US outpost in Jordan.

The fact that the Gravely was not able to intercept the missile sooner does not indicate that the Houthis’ attacks have gotten more sophisticated, a US official said.

According to the Missile Defense Project at the Center for Strategic and International Studies, Tom Karako, it was “concerning” that the Houthi missile managed to get so close to a US warship.

Karako said, “If it’s going at a pretty good clip, one mile translates to not very long in terms of time.”

He explained that the Houthis acquire much of their weapons technology from Iran. A mile can be covered within a matter of seconds even by slower cruise missiles, and the decision time for the commanders of warships is compressed because of the narrow waterways in the Red Sea.

The challenge facing air defense, Karako said, is a “capacity problem,” since US warships have a finite supply of interceptor missiles to use. “We can’t afford to sit here and play catch indefinitely,” he said.

The Houthis have continued to launch missiles and drones at vessels in the Red Sea, however, and on Wednesday morning were preparing to launch a surface-to-air missile that posed a risk to US aircraft operating in the region, according to US Central Command.

The Phalanx CIWS

The Phalanx CIWS (pronounced as “SEE-wiz”) defends navy ships against a variety of anti-ship threats, such as anti-ship missiles and aircraft, small high-speed surface craft, helicopters and surface mines. Phalanx is the only deployed CIWS capable of autonomous search, detection, evaluation, tracking, engagement and kill-assessment functions.

Equipped with a six-barreled 20mm cannon capable of firing over 4,500 rounds per minute, the CIWS can shred incoming projectiles at close range, offering critical protection for ships in high-risk situations.

The Block 1B Surface Mode configuration builds on earlier capabilities with the addition of an Optimized Gun Barrel (OGB) for an improved dispersion pattern and an integrated Forward-Looking Infrared System. The new OGBs are 18 inches longer than the original M61A1 gun barrels, are substantially thicker, and include both a barrel brace and muzzle restraint to improve longevity and projectile dispersion patterns. The Enhanced Lethality Cartridge provides a 50 percent increase in penetration mass. The Phalanx FLIR provides a unique capability to search, track and engage littoral warfare threats while simultaneously providing a significant improvement in ASM engagement ranges.

The Phalanx weapon system is installed on all US Navy surface combatant ship classes and on those of 24 allied nations. The land-based version is forward deployed and has been used in combat.

USS Gravely

USS Gravely (DDG-107) is an Arleigh Burke-class guided missile destroyer in the United States Navy. She is named after Vice Admiral Samuel L. Gravely, Jr. Gravely became the first African-American to command a US Navy warship and the first African- American to command an American warship under combat conditions.

Gravely is the 57th destroyer in her class. She was authorized on 13 September 2002 and her keel was laid down on 26 November 2007 at Northrop Grumman Shipbuilding’s Ingalls Shipbuilding shipyard in Pascagoula, Mississippi. Gravely was launched on 30 March 2009. She successfully completed sea trial in June 2010.

Alma B.C. Gravely, Adm. Gravely’s widow, christened Gravely, Northrop Grumman’s 27th Aegis guided missile destroyer, on 16 May 2009.

USS Gravely is part of the Dwight D. Eisenhower Carrier Strike Group (IKECSG) arrived in the Middle East and CENTCOM area of responsibility on Nov. 4, 2023.

Photo by Lt. Cmdr. Corey Barker/U.S. Navy and Paraxade via Wikipedia

Operation Praying Mantis

Operation Praying Mantis was the largest of five major US Navy surface actions since World War II. According to Naval History and Heritage Command, it was the first, and so far only, time the US Navy has exchanged surface-to-surface missile fire with an enemy, and it resulted in the largest warship sunk by the US Navy since World War II. The trigger for the execution of Praying Mantis was the mine strike by USS Samuel B. Roberts on Apr. 14, 1988. The primary tactical objective of the operation was to sink the Iranian frigate Sabalan. The larger objective was to inflict enough pain on Iran to deter them from laying any more minefields in the Arabian Gulf.

The commander of the operation was Rear Admiral Anthony Less, Commander Joint Task Force Middle East, embarked on the command ship USS Coronado (AGF-11), supported in the Gulf of Oman by Battle Group Foxtrot, commanded by Rear Admiral Guy Zeller, Commander Cruiser-Destroyer Group Three, embarked on USS Enterprise (CV-65).

Operation Praying Mantis kicks off

The US Navy commenced Operation Praying Mantis on Apr. 18, 1988 at 0800 when (Surface Action Group) SAG Bravo, consisting of USS Merrill, USS Lynde McCormick, and USS Trenton, started shelling Iranian guns and military installations on the Sassan gas/oil separation platforms (GOSP).

Meanwhile, nine minutes after SAG Bravo had opened fired on the Sassan GOSP, SAG Charlie, made up of USS Wainwright, USS Simpson, and USS Bagley, targeted the Sirri-D GOSP.

Iran response

In response to the US attacks on the oil platforms, the Islamic Republic of Iran Navy (IRIN) Kamen-class missile patrol boat (PTG) Joshan, under the command of Captain Abbas Mallek, was ordered to proceed to the scene, although the orders were ambiguous as to what exactly she was supposed to do. Approximately three hours later, Joshan was detected closing on SAG Charlie. Captain Chandler (SAG Charlie’s commander and Wainwright CO), on board Wainwright, was well aware from intelligence reports that Joshan was carrying the last operational Harpoon anti-ship missile in the Iranian navy inventory. Chandler later said he would have shot Joshan at 35 miles were it not for the de-escalatory order.

However, as the Joshan and SAG Charlie continued to close at a combined speed of over 50 knots, Wainwright continued to broadcast warnings to Joshan to turn away or be fired upon. Captain Mallek responded on the radio, “I am doing my duty. I am in international waters and will commit no provocative attack.” However, at 13 miles, following yet more warnings, Joshan locked on to Wainwright with her fire-control radar. Chandler issued a last radio warning, “Stop engines, abandon ship, I intend to sink you.” Joshan responded by launching her Harpoon at Wainwright.

A cloud of white smoke

Chandler recalls in the book Harpoon Missile vs Surface Ships US Navy, Libya and Iran 1986–88 by Lon Nordeen;

‘Wainwright was the ship nearest to Joshan as we closed. We reacted very quickly in the wake of Joshan firing at us. The first indication a missile had been launched came from a LAMPS SH-2 Seasprite helicopter, which reported a cloud of white smoke. The senior chief radar operator reported separation [of the solid rocket booster motor from the weapon] and the EW chief reported an emitter. As I said, we had trained for this. Things then went into automatic. The EWs, without order, launched chaff and started the active jamming. I told Simpson we were locked on and gave Capt McTigue the “birds’ free” order to fire his SM-1MR. He fired it immediately. Moments later, we knew Simpson had achieved a hit because Joshan’s radars went quiet.

‘With Joshan having effectively been blinded by the SM-1 hit, I ordered the bridge to steer the ship onto a course that presented the smallest radar aspect to the incoming missile [which, due to its subsonic speed, was still in the air when Joshan was hit by the supersonic SM-1MR] and kept it out of line between the missile and our chaff cloud.

Why the miss?

‘The missile passed very close down our starboard side and, by visual report, through the chaff. Now, why the miss? I surmise one of three things – either the missile malfunctioned, the missile settings were wrong, or the actions Wainwright took were effective. Later, I considered that we might have had some luck, too.

‘How does it feel to have a Harpoon fired at you? Too exciting, and too many things to do and think about. One remarkable thing. As I looked around CIC while the missile was inbound, everyone was bent over with knees flexed, holding on to a fixed object.’

Mk 15 Block 0 Phalanx CIWS

All of the US Navy warships involved in Operation Praying Mantis were fitted with Mk 15 Block 0 Close-In Weapon System (CIWS) Phalanx – the first examples had reached the fleet in 1980, and within five years 400 units had been delivered. The only time it was called into action during either operation was when Wainwright was targeted by a Harpoon fired by Joshan, and the CIWS failed to engage the ASM when it came within range, despite being in auto mode.

Phalanx CIWS fails to shoot down the Iranian Harpoon

‘One of the major concerns following the April 18 clash with Joshan was why did our Phalanx CIWS NOT shoot down the Iranian Harpoon when it was in full auto mode? What happened? I asked my Weapons Officer, who was at my elbow as my TAO, that very question. What we subsequently found out was a huge lesson learned. When you are responsible for weapons systems in a new command, check out the limits on the firing cut-out cams [that protect the CIWS from shooting up its own ship]. We had fired our CIWS numerous times, even in the Persian Gulf, and only a few days before had had a low-level fast aircraft run some tracking passes for us, and all was in order.

Phalanx CIWS incorrectly set firing cut-out cams

‘However, as in all tracking and firing exercises, the missile profiles were flown over the beams of the ship, and none from forward or aft. On investigation and testing, it was discovered that the limits on the CIWS firing cut-out cams had been changed, unbeknown to me and the weapons officer, by one of my predecessors who was concerned some antennae forward might be shot away. Wrong! The engineers who create those limits know what they are doing. That problem was quickly corrected. So, you have the answer – incorrectly set firing cut-out cams.

‘Why did I point the bow at the inbound missile? Training! The three primary reasons were as follows. Firstly, during a session with a tactical training team, the leader asked me where was the ship’s minimum radar cross section. I replied, “bow.” He said, “No, three to five degrees off the bow.” Train, remember. Also, CIWS will engage (supposedly).’

A really bad day for Iran

In response to the Harpoon launch, Simpson fired four Standard missiles in surface-to-surface mode at Joshan and Wainwright fired one. (Although the Standard missile’s anti-air warhead is relatively small, the missile gets to the target extremely fast…and when I was in TAO school in 1982, the instructor hammered that point home.) At least four of the missiles hit Joshan’s superstructure with devastating effect, but not enough to sink the ship.

During Operation Praying Mantis the US Navy destroyed two Iranian surveillance platforms, sank two of their ships, and severely damaged another.

Harpoon Missile vs Surface Ships US Navy, Libya and Iran 1986–88 is published by Osprey Publishing and is available to order here.

Photo by Jim Laurier, PH2 Michael A. Harnar, CWO2 Kenneth H. Brewer / U.S. Navy and Paraxade via Wikipedia

Tomahawk anti-ship missile

The US Navy is gearing up to enhance its submarine capabilities with ship-targeting versions of the highly versatile Tomahawk missile, marking a strategic move to bolster military strength in the face of growing challenges from Chinese maritime forces, especially in the vicinity of Taiwan, Alert 5 reports.

According to The Strait Times, as programme manager Captain Jon Hersey said in a statement, the Maritime Strike version of the Tomahawk, the missile traditionally used as a ground-attack weapon, will be fielded after Oct. 1, 2024.

He also pointed out that the latest models will be modified with a new guidance system enabling them to “engage a mobile target at sea.” Hersey added that the US Navy took delivery of the initial version in 2022 for tests before declaring it combat ready.

By means of the revamped Tomahawk version the US aims to fortify its arsenal of ship-attack missiles. These additions are intended to complement submarine-launched torpedoes and act as a countermeasure against China’s numerically superior naval fleet.

In addition to submarines, the US Navy plans to integrate these missiles into its surface vessels. However, the latter faces heightened vulnerability to China’s anti-ship capabilities, both on land and at sea.

A range of up to 1,600 km

The missiles will be deployed on Los Angeles– and Virginia-class submarines, which can carry as many as 12 land-attack Tomahawks, although some modified versions of the Virginia-class will be able to carry as many as 40. With a range of up to 1,600 km, these missiles provide a significant strategic advantage by offering greater standoff distances from Chinese anti-access and area-denial missile systems.

“The long range provides greater stand-off from Chinese anti-access and area-denial missile forces, and this would complicate Chinese planning for a blockade/invasion of Taiwan,” Mr Brent Sadler, a senior research fellow in naval warfare and advanced technology at the Heritage Foundation, as well as a former submariner and head of the navy’s Asia-Pacific advisory group, explained.

More work is needed

Nevertheless, experts pointed out that to refine strategies on how these missiles will be employed to overwhelm Chinese forces effectively more work is needed. The US Navy’s Submarine Forces Commander, Vice-Admiral William Houston, expressed commitment to deploying the Maritime Strike Tomahawk as swiftly as possible. He highlighted that the dynamic nature of procurement, modernization, and fielding schedules involves various factors, including industrial base capacity and shipyard capabilities.

The arming of US submarines with these advanced ship-targeting Tomahawk missiles marks a pivotal development in naval warfare capabilities, shaping the strategic landscape in the Indo-Pacific region as geopolitical tensions continue to unfold.

The Tomahawk Land Attack Missile

The Tomahawk Land Attack Missile (TLAM) is a long-range cruise missile used for deep land attack warfare, launched from US Navy surface ships and US Navy and United Kingdom Royal Navy submarines.

The Block III Conventional variant (TLAM-C) contains a 1,000-lb class blast/fragmentary unitary warhead while the Submunition variant (TLAM-D) includes a submunitions dispenser with combined effect bomblets. The Tomahawk Block IV (Tactical Tomahawk, TLAM-E), conventional variant, which entered the Fleet in 2004, adds the capability to reprogram the missile while in-flight via two-way satellite communications to strike any of 15 pre-programmed alternate targets or redirect the missile to any Global Positioning System (GPS) target coordinates.

Loitering over a target area

The Block IV missile is capable of loitering over a target area in order to respond to emerging targets or, with its on-board camera, provide battle damage information to warfighting commanders. Tomahawk Block IV is currently in Full Rate Production (FRP). Block IV’s will require mid-life recertification beginning in FY19, increasing the capabilities and extending service life. During recertification, upgrades to navigation and communication systems will be completed. Plans for a maritime strike capability are in development, this enhancement would be executed concurrently with recertification.

Tomahawk provides on-scene commander with the flexibility to attack long-range fixed targets or support Special Operations Forces with a lethal, responsive, precision weapon system and as such has become the weapon of choice for the U.S. Department of Defense.

More than 2,000 Tomahawks fired in combat operations

Tomahawk cruise missiles are designed to fly at extremely low altitudes at high subsonic speeds, and are piloted over an evasive route by several mission tailored guidance systems. The first operational use was in Operation Desert Storm, 1991, with immense success. Since January 1991, more than 2,000 Tomahawks have been fired in combat operations, including in 2011 during Operation Odyssey Dawn in Libya and in 2014 during Operation Inherent Resolve in Syria.

Photo by General Dynamics Electric Boat Image and US Navy

Submarines toilet

Just like surface ships, the toilet on board a submarine is referred to as its head out of traditional maritime custom.

According to SpotyNews.com, compared to their surface cousins, submarines have a much more difficult time dealing with mundane operations including flushing the toilet.

Blowing Sanitaries

A claim confirmed by Dale Rich, former US Navy submariner, on Quora.

Rich explains;

‘Submarines have sanitary tanks that are designed to hold the human waste generated in the heads (shipboard bathrooms in the Navy). These tanks are routinely flushed to the open sea when the boat is in normal operating condition and is usually done when the boat is close to the surface while making routine evolutions at periscope depth. These tanks are emptied by using air stored in the air banks to pressurize the tanks to a pressure that is above the sea pressure exerted on the boat at the depth where the boat is operating. An example would be that if the boat was at 100 feet depth at the keel, the air pressure to remove the waste would have to be above 44psi. This routine procedure is called “Blowing Sanitaries” and is performed by the Machinist gang on the boat.’

Operating in hostile waters

Rich continues;

‘When a submarine is operating in hostile waters, is on a mission to trail an enemy combatant, or is operating at extreme depths, the sanitaries cannot be emptied. There are various reasons for this but the primary reason is that the evolution has the potential to make significant noise and uses vital resources to perform the evolution. If the boat is at extreme depth (below 500 feet) the amount of air needed to remove the waste increases dramatically. (at 500 feet at the keel it would require air pressure to be above 215psi to push the waste from the tank) Air is a vital commodity on a submarine, and might be needed, and better used, to push the submarine to the surface in an emergency rather than being wasted pushing waste out of the sanitary tank.’

Mercy Blow

‘It is not unusual for a submarine to remain in a position where it cannot expose itself for many days at a time. During this time the sanitaries start to fill up, and the heads are restricted. No showers, no laundry, limited use of the head, no extra use of water. Usually this is when the crew begins to beg for a “Mercy Blow.” The officer of the deck is always apprised of the situation and informs the Captain of the problem. Measures are taken to alleviate the situation if possible.

Rich concludes;

‘This is just one more problem that submariners have to deal with, but remember, all of them are volunteers and do the job because they love it!’

Photo by SmarterEveryDay YouTube channel and National Museum of the US Navy

Silent running

Silent running (or ultra-quiet) is a stealth mode of operation for submarines.

During silent running, the propellers have a characteristic RPM band in which no cavitation noise arises. Since this rotation speed is usually relatively low, the first electric submarines had special “silent running” engines designed for optimum performance at reduced speed.

Nuclear submarines can run even more quietly, at very low speeds only, by turning off active reactor cooling during silent running. The reactor is then only cooled by natural convection of the water.

The aim of silent running (a protocol that has been in use since the latter part of World War I, when hydrophones were invented to detect U-boats) is to evade discovery by passive sonar by eliminating superfluous noise: nonessential systems are shut down, as explained above speed is greatly reduced to minimize propeller noise and the crew is urged to rest and refrain from making any unnecessary sound.

As already explained (CLICK HERE to read the article) ‘Being “quiet” is more than not talking.

Slamming hatches and banging wrenches on metal

‘As a US Navy nuke, we loved rig for ultra-quiet,’ Michael Denney, former US Navy submariner, says on Quora.

‘A normal nuke day is 6 hours standing watch, 6 hours maybe off, theoretically 6 hours in the rack, and repeat. If any maintenance was due, it happened during the 6 hours ‘off’. Any ship wide evolutions (drills or all hands clean up) could come during your rack time. During ultra-quiet, if you weren’t on watch it was sweet, sweet bunky time.

‘I’ll leave it to the sonar techs to say how much they could hear, but at the end of every war game with other subs and ships, if it was time for the other guys to find us, the engineering watchstanders would roam around slamming hatches and banging wrenches on metal.’

Denney concludes;

‘They’d usually find us after a half hour of this, but certainly didn’t inspire us to tiptoe on a regular basis.’

Photo by U.S. Navy

Ohio-class SSBN

The Ohio-class SSBN was conceived in the early 1970s and at 560 feet, they became the largest submarines ever built by the US Navy.

USS Ohio (SSGN 726, the first of her class of ballistic missile submarines [SSBNs] and guided missile submarines [SSGNs], and the fourth US Navy ship to bear the name) joined the US Navy on Nov. 11, 1981.

With the end of the Cold War, the first four Ohio-class SSBNs – Ohio, Michigan, Florida and Georgia – were scheduled to be decommissioned in the early 2000s. The other 14 would remain in service as SSBNs carrying the Trident II D-5 missile.

Ohio-class SSBN launching ICBMs

What are US Navy Ohio-class SSBN submarine crews supposed to do afterwards if they really did finish launching their ICBMs?

Steve McDermott, US Navy Nuclear Submariner on Ohio-class SSBNs, explains on Quora;

‘This is assuming a full launch of all loaded missile tubes.

‘Clear datum and go deep. Run. Run as fast and as quiet as possible. What’s left of the enemy or their allies will be in a murderous rage to sink your boat.

‘Psychologically, most, if not the entire crew will have some serious remorse. Killing millions indiscriminately is not really a life goal for anyone, especially a vetted and trained submariner. There may be some attempt by one or two crew to scuttle the ship due to grief. And they may succeed.

‘Depending on where in her patrol cycle she is, she may have to pull in somewhere as early as a couple of weeks. Her remaining sea time will be fraught with danger from within and out.

God help the Ohio-class SSBN crew that ever launch ICBMs

‘She will be lucky to pull in to a friendly port. The best they can hope for is an On The Beach scenario.

‘I know it’s much more morbid than discussing how to rearm (yeah, right) or rolling over into an attack sub mode (SSBNs are real light on fire control compared to an SSN) and one would have to get lucky to survive an undersea encounter.

‘There would be no reason to lash a broom to the #1 scope coming into port, if there’s a port to return to. No reason to announce you’re the last line of defense and you failed miserably.’

McDermott concludes;

‘Those birds can fly, and we prove it regularly to ensure the rest of the world knows we can make them fly. God help the crew that ever launch them, because there will likely be no one else they know to help.’

Photo by U.S. Navy

Secretary of the US Navy Carlos Del Toro announced the name for the future SSN-810 as part of the Navy’s Fleet Week events in San Francisco

Secretary of the Navy Carlos Del Toro announced at the beginning of October that SSN-810, the ninth Block V Virginia-class nuclear attack submarine, will be named after San Francisco, Calif.

Del Toro announced the name for the future SSN-810 as part of the US Navy’s Fleet Week events in San Francisco while he was speaking in the Embarcadero neighborhood on the city’s eastern shore.

“USS San Francisco will build upon the legacy of her namesakes, and will no doubt represent the people of this city and our nation with honor wherever she may sail,” Del Toro said.

Del Toro also announced that former House Speaker Nancy Pelosi (D-Calif.) will be the submarine’s sponsor.

SSN-810 to feature Virginia Payload Module

Being a Block V ship, SSN-810 will get outfitted with the Virginia Payload Module (VPM), a feature introduced starting with the second Block V ship, SSN 803, currently under construction. VPM incorporates four additional large diameter payload tubes in a new hull section located amidships.

Due to their location, each VPM payload tube is capable of carrying seven Tomahawk cruise missiles adding 28 missiles per VPM. VPM reconstitutes the ability to host dry deck shelters, further enhancing SOF capability, and allows the Navy to host additional advanced payloads via multiple ocean interfaces.

Block V hulls include the ten ships procured from 2019 through 2023 (SSNs 802-811).

The fourth ship named after San Francisco

SSN-810 will be the fourth ship named after the city.

“The first San Francisco, a steel-protected cruiser, blockaded Havana, Cuba, during the Spanish-American War and served as a mine planter in the North Sea during World War I,” reads a statement from the Navy.

“The second San Francisco, a heavy cruiser, had an equally distinguished career, participating in operations and engagements at Cape Esperance, Guadalcanal, Guam, the Marshall Islands, and Okinawa during World War II.”

According to USNI News, the most recent was the Los Angeles-class attack submarine, the former USS San Francisco (SSN-711). San Francisco was inactivated from service in 2017.

During its service life, the attack boat collided with an underwater mountain in 200,5 leading to an extensive refit. The hull is now the moored training vessel for the Naval Nuclear Power Training Unit in Charleston, S.C.

The naming of SSN-810 follows Del Toro’s announcement in May at New York Fleet Week that Block V Virginia attack boat SSN-811 would be named after Long Island.

Virginia-class nuclear attack submarines

The Navy continues to build the next-generation attack submarine, the Virginia (SSN 774) class. Twenty-one Virginias have been commissioned to date, and they will replace Los Angeles Class submarines as they retire.

The Virginia class has several innovations that significantly enhance its warfighting capabilities, including in littoral — or coastal — operations.

The class has special features to support SOF, including a reconfigurable torpedo room which can accommodate a large number of SOF personnel and all their equipment for prolonged deployments, as well as future off-board payloads.

The class also has a large lockout truck (LOT) for divers. In Virginia-class SSNs, traditional periscopes have been supplanted by two photonics masts that host visible and infrared digital cameras atop telescoping arms. With the removal of the barrel periscopes, the ship’s control room has been moved down one deck and away from the hull’s curvature, affording it more room and an improved layout that provides the commanding officer with enhanced situational awareness.

Additionally, through the extensive use of modular construction, open architecture, and commercial off-the-shelf components, the Virginia class is designed to remain state-of-the-practice for its entire operational life through the rapid introduction of new systems and payloads.

Photo by U.S. Navy

Ultra-quiet mode of operation

Silent running (or ultra-quiet) is a stealth mode of operation for submarines.

During silent running, the propellers have a characteristic RPM band in which no cavitation noise arises. Since this rotation speed is usually relatively low, the first electric submarines had special “silent running” engines designed for optimum performance at reduced speed.

Nuclear submarines can run even more quietly, at very low speeds only, by turning off active reactor cooling during silent running. The reactor is then only cooled by natural convection of the water.

The aim of silent running (a protocol that has been in use since the latter part of World War I, when hydrophones were invented to detect U-boats) is to evade discovery by passive sonar by eliminating superfluous noise: nonessential systems are shut down, as explained above speed is greatly reduced to minimize propeller noise and the crew is urged to rest and refrain from making any unnecessary sound.

As already explained (CLICK HERE to read the article) ‘Being “quiet” is more than not talking.

Monitoring the ship’s noise

A claim confirmed by Robert Williscroft, former US Navy Sonar Technician Submarine, who recalls on Quora;

‘I was an enlisted submarine sonar tech and subsequently a commissioned officer on two nuke subs. As a sonar tech, I was in charge of monitoring ship’s noise and helping solve critical noise situations. As an officer, among other things, I was the Sonar Officer.

‘Our decks were sound mounted so that noise was not supposed to enter the water through the hull. Inevitably, however, sound shorts would develop, and as a sonar tech it was my job to find them throughout the sub. (The engineering guys “loved” me!)

‘Equipment on submarines, especially rotating or vibrating equipment, are normally sound-mounted so that they are isolated from the hull. A sound short is when the sound mounting is bypassed so that the sound passes directly into the hull. This can be a piece of metal touching both the equipment and the hull or even a worn-out sound mount.

US Navy Submarines going at “ultra-quiet”

‘When at Ultra-quiet (silent running), the idea is to avoid all possible sounds. Sound can find its way into the water and, depending on circumstances, can be detected at great distances. I have heard Russian conversations between Soviet sub crewmates miles away under the Arctic ice pack. The Soviets did not really understand sound-quieting as we practiced it on our subs. (The Russians are well aware of our sonar capabilities, because every time they do something, we are there dogging them.) A significant part of that was (and is), at Ultra-quiet get into your rack if you don’t have something to do that is specifically required at that moment.’

Williscroft concludes;

‘If you were a sonar tech in another sub 100 yards distant from one of ours when it went to Ultra-quiet, it would suddenly seem to have disappeared—there one moment, gone the next.’

Photo by Photographer’s Mate 2nd Class Lynn Friant and Photographer’s Mate 1st Class Kevin H. Tierney / U.S. Navy

‘Yes. If a Trident submarine launched all of its missiles the water that backfilled into the now empty tubes would not have enough weight to keep the submarine sufficiently negatively buoyant to remain submerged,’ James Clark, former US Navy Submarine Chief Petty Officer

The Ohio-class SSBN was conceived in the early 1970s and at 560 feet, they became the largest submarines ever built by the US Navy.

USS Ohio (SSGN 726, the first of her class of ballistic missile submarines [SSBNs] and guided missile submarines [SSGNs], and the fourth US Navy ship to bear the name) joined the US Navy on Nov. 11, 1981.

With the end of the Cold War, the first four Ohio-class SSBNs – Ohio, Michigan, Florida and Georgia – were scheduled to be decommissioned in the early 2000s. The other 14 would remain in service as SSBNs carrying the Trident II D-5 missile. But another plan was in the works – to use the versatile Ohio seaframe to carry Tomahawks or other payloads in lieu of ballistic missiles. The result would be four platforms capable of supporting strike or special warfare missions around the world.

Under then plan, 22 Trident launch tubes were reconfigured to carry either canisters containing seven Tomahawks each – for a total of up to 154 missiles.
Giving these unique features, the Ohio-class submarines provide the Navy with unprecedented strike capabilities.

But how true is the rumor that Ohio-class submarines lack enough ballast to remain submerged after they fire all of their submarine-launched ballistic missiles (SLBMs)?

James Clark, former US Navy Submarine Chief Petty Officer, explains on Quora;

‘This is a misconstrued statement.

‘Yes. If a Trident submarine launched all of its missiles the water that backfilled into the now empty tubes would not have enough weight to keep the submarine sufficiently negatively buoyant to remain submerged.

‘A Trident D5 missile has a mass of 59,000 kg. Water of the same volume has much less mass. The difference is so large that if multiple missiles have been fired then the trim system would be incapable of handling it, thus the existence of a separate system. That is why onboard the ship between the ship’s compartments are massive compensation tanks that extend from the top to the bottom of the ship and side to side and couple feet in length. Think of them as a giant spacer between the compartments.’

Clark concludes;

‘These are flooded during launch to bring on extra water to maintain proper buoyancy.’

Photo by Photographer’s Mate 2nd Class Lynn Friant / U.S. Navy

‘He ended up cracking the “local control” switch for the control rods before I was able to intercept and subdue him,’ James Thompson, former Electronics Technician aboard US Navy submarines

America’s submarines have come a long way since the first hand-cranked wooden rigs. Today’s state-of-the-art vessels are able to support hundreds of sailors working and living together under the sea for months at a time.

Serving on a US Navy submarine crew takes courage, stamina and deep expertise — literally.

“I don’t think being on a submarine is for everybody. I think you have to be somebody that can be comfortable with no sun and no outside communication. Submariners are different from everyone else in the Navy. There is also a different kind of camaraderie down here,” Navy Petty Officer 2nd Class Khamani Conklin, Torpedoman’s Mate, aboard USS Maine (SSBN-741) Ohio-class ballistic missile submarine, says in the article Living in the Deep appeared on Department of Defense website.

Because of this unique environment has anyone in a Navy submarine ever lost their mind being stuck underwater for months at a time?

‘Oh, yes. I have even been a witness to that firsthand,’ James Thompson, former Electronics Technician aboard US Navy submarines, says on Quora.

‘During a 6-month deployment, we had a sailor that had a mental break during covert ops (basically we were supposed to remain as quiet as can be for weeks/months in a row to do surveillance). I happened to be on watch in the engine room when this sailor came back in the engine room and grabbed a wrench and started bashing the cabinets that controlled the engine room equipment. When I came across him, he was ripping parts off of one of the cabinets that provided backup (local) control of the reactor. He ended up cracking the “local control” switch for the control rods before I was able to intercept and subdue him.

‘Long story short, we had to divert for repairs as soon as we were able to do so (we also had a bad bearing in one of the Main Sea Water pumps, that resulted in a reduced ability to maintain higher propulsion speeds), so we had to go “off station” and get parts to conduct repairs. As soon as we were in port for repairs, that sailor was taken off due to his mental issues.’

Thompson concludes;

‘Having a sailor have a mental issue that resulted in temporary or even permanent reassignment was pretty common during that CO’s tenure on my submarine.’

Photo by U.S. Navy