4 ms·

Regression test: “torpedo explodes when it hits stuff” feels like the constructor test that everyone writes and never expects to fail.

pjc50 7y ago
> The Mark 14 torpedo cost more than $10,000 in an era when a new car cost $700. It was too expensive for live testing.
- WalterBright 7y ago
  Seems to me, if you put a dummy warhead in it of the correct weight you could test it over and over again until the mechanisms worked correctly. It's not necessary to actually blow up a ship in testing, just that the torpedo hit where it was aimed, and the firing mechanism fired.
  - wffurr 7y ago
    They did use dummy warheads and that was part of the problem. The dummies didn't match the weight of live warheads exactly.
    - WalterBright 7y ago
      Getting the weight wrong doesn't seem to be an expense issue.
- C1sc0cat 7y ago
  As compared to a Battleship or A Carrier
- vonmoltke 7y ago
  It wasn't just cost. The USN considered the magnetic influence detonator to be such a potential difference-maker that it didn't want potential adversaries to know it even existed. That feature was not adequately tested because the USN felt testing would reveal it.
- cafard 7y ago
  Yet somehow the Japanese tested the far superior "Long Lance".
  - hackeraccount 7y ago
    I think the Germans and the Americans both looked at the question "How do you get a torpedo to sink a boat when they put armor on the sides where the torpedo will strike?" and came up with answer: Have it explode under the boat not on the side. The Japanese just said - have a larger warhead. The problem for them was that you then need a more powerful motor to drive that larger warhead but they didn't screw that up. The odd thing is that the Germans and Americans (but not the Japanese) mainly used submarines to sink lightly armored commerce ships not heavily armored warships.
nosianu 7y ago
You don't really want to "hit" anything directly. You want the torpedo to pass and explode underneath the target. > The design for the Mark 6 exploder used in the Mark 14 torpedo had started at the Naval Torpedo Station (NTS), Newport, in 1922. Ship's armor was improving with innovations such as torpedo belts and torpedo blisters (bulges). To circumvent these measures, torpedoes needed larger warheads or new technology. One option would use a fairly small warhead but was intended to explode beneath the keel where there was no armor. This technology required the sophisticated new Mark 6 magnetic influence exploder, which was similar to the British Duplex and German models, all inspired by German magnetic mines of World War I. The Mark 14 shared this exploder with the concurrently-designed surface ship Mark 15 torpedo. https://en.wikipedia.org/wiki/Mark_14_torpedo https://en.wikipedia.org/wiki/Mark_14_torpedo

pjc50 7y ago

> The Mark 14 torpedo cost more than $10,000 in an era when a new car cost $700. It was too expensive for live testing.

WalterBright 7y ago
Seems to me, if you put a dummy warhead in it of the correct weight you could test it over and over again until the mechanisms worked correctly. It's not necessary to actually blow up a ship in testing, just that the torpedo hit where it was aimed, and the firing mechanism fired.
- wffurr 7y ago
  They did use dummy warheads and that was part of the problem. The dummies didn't match the weight of live warheads exactly.
  - WalterBright 7y ago
    Getting the weight wrong doesn't seem to be an expense issue.
C1sc0cat 7y ago
As compared to a Battleship or A Carrier
vonmoltke 7y ago
It wasn't just cost. The USN considered the magnetic influence detonator to be such a potential difference-maker that it didn't want potential adversaries to know it even existed. That feature was not adequately tested because the USN felt testing would reveal it.
cafard 7y ago
Yet somehow the Japanese tested the far superior "Long Lance".
- hackeraccount 7y ago
  I think the Germans and the Americans both looked at the question "How do you get a torpedo to sink a boat when they put armor on the sides where the torpedo will strike?" and came up with answer: Have it explode under the boat not on the side. The Japanese just said - have a larger warhead. The problem for them was that you then need a more powerful motor to drive that larger warhead but they didn't screw that up. The odd thing is that the Germans and Americans (but not the Japanese) mainly used submarines to sink lightly armored commerce ships not heavily armored warships.

nosianu 7y ago

You don't really want to "hit" anything directly. You want the torpedo to pass and explode underneath the target. > The design for the Mark 6 exploder used in the Mark 14 torpedo had started at the Naval Torpedo Station (NTS), Newport, in 1922. Ship's armor was improving with innovations such as torpedo belts and torpedo blisters (bulges). To circumvent these measures, torpedoes needed larger warheads or new technology. One option would use a fairly small warhead but was intended to explode beneath the keel where there was no armor. This technology required the sophisticated new Mark 6 magnetic influence exploder, which was similar to the British Duplex and German models, all inspired by German magnetic mines of World War I. The Mark 14 shared this exploder with the concurrently-designed surface ship Mark 15 torpedo. https://en.wikipedia.org/wiki/Mark_14_torpedo https://en.wikipedia.org/wiki/Mark_14_torpedo