September 9, 2021

Taigei submarine has longer (probably stealthier) Fin

 On September 5, 2021 Anonymous kindly provided the following comment:

Sea trials of latest Japanese submarine, Taigei (SS-513) have started [1]. The fin of Taigei-class submarine (Taigei) is longer than the fin of Soryu-class submarines as shown in video and picture [2, 3, 4].



[1] The video here and above depicts the “Departure of Taigei (SS-513) for sea trials.” This may be the first video of Taigei in motion under its own power. The video was uploaded on August 21, 2021.

[2] See a clear, full side on, view of the length of Taigei's fin 1 minute 50 seconds into the same video.

[3] Compare this with the appearance of the fin length of Soryu Mark 1 Hakuryu
 (SS-503) below. See Wiki entry for Soryus and Submarine Matters' Oyashio-Soryu-Taigei TABLE (by scrolling one quarter down here).




[4] The all important Length/height ratio of the fin is 2.4 for the Taigei-class and 2.1 for the Soryus (including Hakuryu).

Pete Comment

Reasons for the longer Taigei fin may include the Taigei accommodates, or can accommodate, more masts, antennas and a larger sonar sensor area (if a hull mounted sonar extends to the fin). Also the Taigeis may/will have Japan's upgraded (tolerates higher sea state) snorkel - which may have different space needs.

Other reasons maybe - Taigei's fin may provide:

-  greater hydrodynamic efficiency

 and

-  quieter acoustic signatures (see "reduce fluid noise") against:
   = opponent's passive sonar and
   = overall lower profile fin for improved sound wave deflection against active sonar
      "interrogation". 

Anonymous and Pete

3 comments:

  1. GhalibKabir9/13/2021 6:39 PM

    Taigei is a superb LiB SSK

    A pity it won't be available off the shelf in an export version....

    ReplyDelete
  2. Pete9/13/2021 8:50 PM

    Hi Ghalib

    True. However, if "retired" Japanese employees of KHI and MHI are indeed helping Taiwan with an indigenous sub then a lower specs de facto Japanese export sub may result.

    However it will likely not have Japan's special pressure hull steel for very deep diving. In particular Japan would not distribute its Lithium-ion Battery technology to any country - especially one likely to be compromised by Chinese/PRC intelligence.

    Similar goes for India and its likely penetration by Russian intelligence way back to the 1960s. Major purchases of Russian and other foreign built jets and subs are worth the seller "packaging" intel penetration via the seller's training staff and advisers - in the seller's country and the buyer's.

    Australia is also not immune to this vulnerability from UK (from about 1908 when we began buying UK warships in a big way) US, France, Spain etc.

    Also Taiwan may be unprepared to pay the big bucks that sensitive inventions can buy.

    Pete

    ReplyDelete
  3. Anonymous9/16/2021 12:34 PM

    I thought the trend is towards tiny fins when you look at next gen US SSN and SSBN.
    KQN

    ReplyDelete

You can comment :)