Daily Dose of Splodey

The Mk45 5”/54 gun was, until recently, the standard in production medium caliber gun for US Navy warships, being replaced in production (but not in existing fleet units) by the Mk45Mod4 5”/62 gun, which is mechanically almost identical, but has a longer barrel for greater range. It fires the same ammunition as the earlier 5”/54.

Here’s an older video, dating from the early 1990s showing a demonstration of the lethality of proximity fused rounds against simulated truck type targets.

The “HECVT” projectile stands for High Explosive Common Variable Time. That is, it’s a high explosive shell. Common means it is a general purpose round, as opposed to having an armor piercing body, or prefragmented anti-aircraft body. It is, by far, the most common round- hence, Common. Variable Time oddly doesn’t stand for Variable Time, but instead for Proximity fused. That is, a small radio transmitter in the nose of the fuse senses when the round is within a predetermined distance from an object, and then initiates the bursting of the charge. Variable Time was a cover story from when VT was invented in World War II to keep the Germans or Japanese from discovering how VT worked, and either developing their own, or countermeasures to defeat it.

[youtube https://www.youtube.com/watch?v=AS5G-NwPlWo]

4 thoughts on “Daily Dose of Splodey”

  1. Just a few corrections here:

    – There isn’t an ‘Aegis-Class.’ Aegis is a system on TICONDEROGA- and ARLEIGH BURKE-class ships.
    – Fuse types: Time (Ti), Variable Time (VT), and Controlled Variable Time (CVT), among others.
    – Ti fuses have the time delay between firing and fusing (exploding) manually set. Thus, the time delay is ‘fixed,’ but allows changing of the Height of Burst (HOB)
    – VT fuses have a proximity fuse so that the shell explodes a consistent 20m above the target (foliage and other obstacles will set it off as well). There is a variable amount of time between firing and the 20m HOB. This fuse is unsafe for overhead fire.
    – CVT is a proximity fuse that explodes at a 7m HOB. It does not arm until later in flight and is ‘safe’ for overhead fire.

    I can’t comment on the secrecy claim.

  2. These days there’s more than one type of “V” for the VT. VT-RF is the historically most common side described above, but there’s also VT-IR, with an infrared sensor instead of using reflected RF energy.

    And oh, the sea stories that I wish I could post here … 😀

  3. LT R:

    Thanks for the update. It’s been many years since I went through EWTGPAC or been out in the field.

    Yes, mine all begin and end with ‘no sh*t.’ 😉

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