Korean Aegis Warship Could be Torpedoed by Enemy For Noise

Article from Yonhap News:

One Trillion Won Aegis Warship Likely to Be Detected By Enemy Because of Noise

The photo shows south Korean Aegis warhip is sailing in waters. The photo shows South Korean Aegis warship sailing in waters.[/caption]


South Korea’s Aegis warship, one of the core military assets of South Korea in establishing “Kill-Chain” and “KAMD” systems–two requisites to be fulfilled before South Korea retakes wartime operational control from the United States–is revealed to have operational problems after being deployed.

The warship, which is now in service, is known to produce the level of noise underwater that can be detected by an adversary for torpedo attacks. This is a grave defect with no methods of correction, leading to several hundreds of millions won in fines for the part supplier.

Our reporter Hwang Hye-kyoung has more.


“Sejong the Great” is the first Aegis warship that our navy deployed in December 2012.

Costing a whopping one trillion won (roughly $10 billion), the state-of-the-art naval warship was found to have a grave defection three months before it was put into service. One underwater propeller on the warship has a noise level exceeding the standard.

Measured usually by two criteria, called URN (unterwater noise) and CIS (cavitation interception speed), the underwater noise, generated by Sejong the Great, resulted in unsatisfactory grades for the warship in a previous assessment of both criteria. What confounds the problem is that the same defects were also discovered in two more Aegis warships–Yeulgok Yiyi, and Seohae You Seongryong, pointing to a possible structural fault.

Underwater noise creates sound waves, providing an enemy with clues to pinpoint its existence for torpedo attacks, so warships carry deceptive bombs with similar noise levels to draw adversary attacks toward a target in place of the warships themselves. Accordingly, noise levels from warships are classified as confidential military information.

[Kim Byung-ki, editor of the Defense Times]

The louder the noise of the warship, the easier it is for the enemy to detect the warship at a distance in a short amount of time. This means we could be identified by the enemy before we can discover the enemy. A slight difference in the noise levels leads to detection at a slightly larger distance, allowing the enemy to launch an attack on us while we are unaware of the enemy’s existence.

The military authorities are reported to have glossed over the noise problem as its discovery was made just ahead of deployment in waters, while imposing four trillion won in fines on the part supplier to Sejong the Great. This passivity is in stark contrast to the Tongyoung warship which was rejected for takeover over the problematic performance of a sonar attached to it.

[Rep. Ahn Kyu-baek of the ruling Saenuri Party]

North Korea has a fleet of 77 submarines in its possession… and the East Sea is a great place to detect submarines as the sea is expansive and offers clear visibility. If we don’t resolve the noise problem, our navy could be put in great peril.

Critics in particular say that a confidentially classified noise standard for Sejong the Great was not featured in operation performance requirements and claimed that the non-inclusion caused a total $3 trillion of the Aegis project to be utilized in an haphazard way.

This is YTN Hwang Hye-gyeong.

The Sejong the Great Aegis warship failed to pass two crucial noise standard tests, raising the grim prospect of an early detection by the enemy for torpedo attacks.

The Sejong the Great Aegis warship failed to pass two crucial noise standard tests, raising the grim prospect of an early detection by the enemy for torpedo attacks.

Comments from Yonhap News:


We don’t have anyone who can take good care of state affairs.


Whoa, somebody else must have put the money into their pocket. I have no expectations for this country. This is why people want to emigrate to another country.


Military officers are playing golf at this moment.


I think capital punishment is the only answer to those who commit acts of corruption in the military.


There are so many mapias out there. [Mapia is the term referring to corrupt officials using their connections.] But I think the evilest are militarypia [a newly-coined term from military and mapia]. If there is a war, soldiers and we citizens will be powerlessly dead due to corruptions in the military.


This case could bring about death by firing squads in China. All part suppliers and military officers responsible should be prosecuted for undermining national security. Delve further into the scandal, and set a precedent of harsh punishment as a warning for potential crimes. What a bastard!


An enemy attack will sink the warships in a war. Now, we are pushing the country toward a path of demise. They did a good job.

Comments from Yonhap News:


Our enemy is not North Korea but some corrupt bastard star generals in the defense ministry.


Well, that’s what they have been doing so far, I have no expectations for them. They siphoned money away and look the other way when it comes to corruption. A shoddily-build Aegis warship could bring about nuclear bomb-level damage to us.


South Korea has three Aegis warships: One is overseas to guard commercial vessels, and another one is in repair; the other one is frequently out of order, failing to show its desired performance. Aegis warships are touted as capable of detecting thousands of targets at a time, and intercepting missiles. Those in power take gains by emphasizing security, making national defense a distant dream.

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  • Xman2014

    There goes the South Korean media squawking again. If they really are interested in uncovering the truth, then maybe they should do a little bit of research on the nature of these Aegis ships before they turn them into an end of the world, the sky’s falling stories. Instead of printing emotional drivels again, they could have broken down the information and analyzed it properly.

    The fact of the matter is, if the most powerful US navy are not very good at locating small diesel powered submarines operating in shallow coastal waters, the South Korean navy isn’t going to be any better.


    • seno

      the USS COLE Arleigh Burke Aegis NEVERS goes into shallow foreign waters again after it was torpedoed by a suicide boat in Yemen.in year 2000


      • takasar1

        we call that a2/ad. no one has a surefire answer for it yet.

    • commander

      I don’t understand your point.

      The above article’s main point is that South Korea’s aegis warship, which is NOT a SUBMARINE, is uncovered to produce a higher level of noise than relevant standards from its underwater propeller, thus giving clues for its presence to enemy, which is North Korea, a grave defect that increase the possibility of the warship being subject to torpedo attacks by North Korean submarines.

      The article, provided by the link you posted, say that many US aircraft carriers have failed to detect diesel-electric submarines “in noisy, shallower waters near coastal areas,” in naval exercises, raising concerns about performance of American fleets of aircraft carriers.

      I can’t understand what relevance there is between South Korean Aegis warships with noise problems from faulty parts installed on them, and the failure of American aircraft carriers to identify submarines.

      • Guest

        You obviously have no clue in naval matters to pose this type of question. An aircraft carrier doesn’t sail by itself only. It’s got a convoy of ships including the ship in question to protect the aircraft’s perimeters.

        • commander

          You obviously have no knowledge of the aegis warship mentioned in the article.

          The Sejong Great aegis is NOT an AIRCRAFT. The point in the article is noise from the aegis warship could fasten its sinking by torpedo attacks at a far more distance than expected by the enemy noticing the aegis ship’s presence.

        • Ken Morgan

          The British ones do… because we (the UK) can’t afford a screening fleet for the new Queen Elizabeth class carriers… nor can we afford air craft for those carriers. Or a crew either. The 2nd carrier is due to be sold for scrap the moment it is completed!

      • Jack


        • commander

          As ethnically homogeneous state, South Korea has strong nationalism, so sometimes Koreans are seen as having strong self consciousness.

          But the same is applied for other countries.

          The United States coined the concept of American exceptionalism, which means the United States is built on a new land by God’s will and superior to other countries l, thus having a mission to guide other countries by setting an example.

          China used to call itself the center of the world, and such a perception is latent in Chinese people’s mind.

          Britain, Japan, Israel and etc.

          I think your cynicism cloud your judgement.

    • elizabeth

      In other words, they are missing the forest for the trees.

  • 금정산

    The article says “This is a grave defect with no methods of correction”.

    Does this mean the propeller cannot be replaced? I find it difficult to believe that a ship would be designed such that its propellers (including engine and shafts) are irreplaceable.

    • Dave Park

      I don’t know much about the designs of warships but… I don’t think this has to do with the propeller.

    • commander

      Some misunderstanding. “There is a grave defection with no methods of correction,” means here that the navy took no measures to rectify the problem before they sent the aegis ship into service.

      • Sid Driver

        Thanks for the clarification… I was thinking the same as Jeongsan myself.

        • commander

          You’re welcome. Thanks for visiting to koreaBang.

      • 금정산

        Thanks for the good work.

        • commander

          It’s my pleasure. Thanks for your interest in koreaBang, and your commentaries.

  • Small twon

    I thought “what ?? how could they let it happen ?” until I saw news source .. Defense Times is Not a news paper. It is more like amateur military club magazine.They even can’t sell their magazine,so they dumped it.Their monthly magazine goes directly to used bookstore and sold as a 2 dollar cheap magazine along with other yellow paper.

    • Guest

      Commander deletes all my rebuttals because I say this is a phoney manufactured issue by the press, and he doesn’t agree.

      Please post this link which puts everything into perspective and explains why the navy is convinced this is not a problem, so that others can read also.


      • commander

        The article, a click on the link takes a reader to, contains the following part that is relevant to the problem of higher noise fro one propeller on the aegis warship in the above article.

        “이지스함 엔진 소리까지 방송을 내 보내는 것은 소음과 무관한 것으로 저질 방송이다. 조선소 문제가 아니라 프로펠러 문제이며 유일한 프로펠러 제작업체의 수준이며 우리나라의 기술 수준이라고 봐야 한다. 적은 예산과 짧은 기간에 함정을 건조하므로 다소 결함이 있을 수 있지만 북한 장거리 미사일 발사를 미국, 일본보다 먼저 탐지한 세종대왕함이다.”

        Translation by me:

        “Airing out a TV program, claiming that engine sound from an aegis warship, is problematic because the engine sound has nothing to do with noise. It is not a problem with a shipbuilder but a problem with propeller, which is manufactured by the only single propeller maker in South Korea, in a reflection of a technology level in South Korea. Although there is some defects because the aegis warship was manufactured with a tight budget in a shorter period, it is the Sejong Great Aegis warship that detected long-distance missiles launched from North Korea earlier than the United State and Japan.”

        For information of other readers, I want to say that the author of the article, from which the above quote is taken out, is a retired one-star navy general.

        This post’s article raises the question of the same issue as the retired navy general admitted: Higher level of noise from one propeller on the aegis warship.

        The translated article has never said the Sejong Great Aegis warship is under-performing, it just says that it has a problem with the propeller on the vessel.

        Finally, I have never deleted your rebuttals, though have some disagreement with you on the issue that I think you have some misunderstanding.

        This place is a forum of visitors, so I have no reason to delete opinions of a person who have different ideas from mine and I have no authority to erase that person’s comment.

        • Guest

          If you didn’t erase all my posts replying to you below, then who did? They were there when I posted them, then dissappeard after about a minute later.

          Your translations are a bit off on this part.

          “이지스함 엔진 소리까지 방송을 내 보내는 것은 소음과 무관한 것으로 저질 방송이다”

          Should have been translated to:

          “To report on engine noise of Aegis has nothing to do with noise, and it’s a poor news reporting”.

          조선소 문제가 아니라 프로펠러 문제이며 유일한 프로펠러 제작업체의 수준이며 우리나라의 기술 수준이라고 봐야 한다

          “This is not a problem with ship builder, it’s the level of the lone propeller manufacturer, and that’s the level of our country’s technology. ”

          (meaning there was no bribes, no negligence, no short cutting, or irregularities as claimed by you and the news report – it is what it is – and there is no evidence anywhere that propellers from US manufacturers are anymore silent than the Korean one).

          And how convenient of you to leave out the rest of his writings. For instance, would you care to translate this now?

          24시간, 한 달 이상 험한 파도와 진동 속에서도 이 정도 고장이라면 기적 같은 일이다. 전 세계적으로 이런 해군이 있다는 것이 신기하고 사실이라면 칭찬과 표창을 해야 한다. 송 모의원은 잘 모르고 함부로 지적하지 말길 바란다. 그리고 그는 자료만 언론에 흘리고 국감장에서 질문도 안했다.

          Read the whole report by him, you really don’t think he’s saying there’s not a big problem? My honest impression of his article seems to be he’s praising the Korean Aegis ships and think the Korean news is over reacting.

          • commander

            Well, regarding the disappearance of your comment has nothing to do with me.

            A technical glitch with the site may be blamed for it. And I had that kind of several experiences several times before. Why do you continue to accuse me of doing your comment removal, which I have never done and have no authority to do?

            If I did it, why I left your other comments intact, blaming me for erasing your comments? It doesn’t make sense at all. I am INNOCENT, and you are pointing a FASELY accusing finger at me without grounds. If you got me wrong, you should take your words back.

            Second, I am not trying to undercut service of active navy sailors which are doing their duties on aboard around the clock, and not trying to cast Korean Aegis warships as under-performing.

            The problem the article points out and I am saying is that there are some noise problems with one propeller on the warship. Simple and plain.

            If that is a result of the nation’s present technology level, then you can just say that the investment needs to be made in developing better proprietary technology enabling the manufacturing of test-passable propellers.

            You, as in falsely accusing me of eliminating your reply, are falsely blaming me for what I never criticized aspects of the Korean Aegis warships.

            Let’s stop here.


            You are right to say that Defense Times is a private magazine and may have less expertise on Korean warships than active or retired military officers. But the reporter presumably can’t get an interview with those officers because no one would come forward to take up an interview request out of fear of any kind of retribution usually expected for whistle-blowers, even though he revelation is only about small problems. It is all the more so when the interview is about classified information.

            (The posted article say noise from warships are confidential information because the revealed noise level information could make it easier for enemy to spot our warships by allowing them to adjust their noise detecting ability.)

            That’s, I think, why the reporter turn to the editor of the military magazine to back up the main point of his or her article.

          • Small twon

            .huh ? I am not a guest guy .

        • Guest

          과거 214급 잠수함 소음 문제에 대해서는 이미 쓴 적이 있으며 209급 잠수함보다 소음수준을 아주 낮게 정하다 보니 특정주파수대만 기준치를 약간 초과한 것이지 실제로 조용한 잠수함이다. 이번 이지스함 문제도 과거의 함정과 비교하여 세 가지 스텔스 기능이 추가되어 타 수상함이나 잠수함에서 탐지하기가 쉽지 않다.

          In this part, he also totally denies the news reports that the Aegis will be discovered easily because of the noise, instead says it is still very difficult for the subs to break the ship’s stealth. The standards of stealth has been strengthened and raised, compared to the past, and not meeting them at 100% target does not mean the ships are no good.

          • commander

            Then, my question is why the standards are raised in the first place when not fulfilling the tightened criteria is not that important wit few adverse effects on warships.

        • Guest

          Are you deliberately trying to mistranslate to fortify your own point? I’m talking about your translation here.

          “Although there is some defects because the aegis warship was manufactured with a tight budget in a shorter period, it is the Sejong Great Aegis warship that detected long-distance missiles launched from North Korea earlier than the United State and Japan”

          That’s not what it says. You should have translated to:

          “Although defects may appear when the ships are manufactured under such tight budget and short schedules”
          He does not claim there are any defects at all! He saying even under such conditions, yes there COULD be some defects which would not be unusual, but the bottom line is the Aegis ships were able to perform better than the older US and Japanese Aegis ships.

      • sane

        because we have enough idiotic korean nationalists in SK already, we don’t need your kind here.

  • waygookinhanguk

    As a product of a noisy country, why am I not surprised?

    On a serious note, the fines are a racket. A defect apparently judged serious enough to impose swinging fines yet deployment goes ahead anyway. Of course the companies can’t squeal too loudly or they could lose their next lucrative government contract. And they probably didn’t obtain the past ones without some (ahem) monetary lubrication applied to the wheels of the deal.

  • Racist bozos are brainless

    “Costing a whopping one trillion won (roughly $10 billion)” -Actually, 1 trillion won is roughly $1 billion, not $10 billion.

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