# Ship launches missile that goes underwater before ignition, but why? **URL:** \ **Category:** Factual Questions\ **Created:** [March 28, 2012, 4:33pm UTC](https://boards.straightdope.com/t/ship-launches-missile-that-goes-underwater-before-ignition-but-why/617057 "2012-03-28T16:33:00Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![Dissonance](https://avatars.discourse-cdn.com/v4/letter/d/85f322/32.png) [@Dissonance](https://boards.straightdope.com/u/Dissonance)\ **Post date:** [March 29, 2012, 4:24pm UTC](https://boards.straightdope.com/t/ship-launches-missile-that-goes-underwater-before-ignition-but-why/617057/21 "2012-03-29T16:24:21Z")
> [@Boyo\_Jim](#): > > If the target submarine can’t hear the firing ship, that missile must have a very long range. Sonar can detect ships from dozens to even hundreds of miles away, and it’s almost impossible to believe the sub couldn’t hear the underwater ignition of the rocket motor. Past the initial couple of dozen miles sonar is using convergence zones where sound will return to the surface at regular intervals of every 30 or so miles. The SS-N-16 has a range of 100-120km, so it could be fired at a contact at the first or second convergence zone, possibly the third. Convergence zone contacts tend to be spotty, fading in and out so you won’t get anything like an exact fix, just an area in which the sub or ship is located. > [@](#): > > One of the main criticism of the SUBROC family of weapons – these are anti-submarine torpedoes fired from ships on a rocket booster – is that even with the rocket assist, they are so short range that the ship has to get withing range of the submarine to deploy it. There’s one thing about SUBROC in particular that demonstrates the more practical use of these sorts of weapons on area contacts. [SUBROC](http://en.wikipedia.org/wiki/UUM-44_SUBROC) doesn’t have a conventional payload option. It only carries a W55 nuclear depth bomb unlike ASROC and such which carry either a torpedo or a nuclear depth bomb. ---
**Author:** ![Otara](https://avatars.discourse-cdn.com/v4/letter/o/a88e4f/32.png) [@Otara](https://boards.straightdope.com/u/Otara)\ **Post date:** [March 29, 2012, 9:42pm UTC](https://boards.straightdope.com/t/ship-launches-missile-that-goes-underwater-before-ignition-but-why/617057/22 "2012-03-29T21:42:01Z")
“If the target submarine can’t hear the firing ship, that missile must have a very long range.” It does, and of course, I forgot the other obvious advantage - a missile is a lot faster than a torpedo, which reduces reaction times. Otara ---
**Author:** ![SunSandSuffering](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@SunSandSuffering](https://boards.straightdope.com/u/SunSandSuffering)\ **Post date:** [March 30, 2012, 7:56am UTC](https://boards.straightdope.com/t/ship-launches-missile-that-goes-underwater-before-ignition-but-why/617057/23 "2012-03-30T07:56:53Z")
It kind of reminds me of the [Javelin](http://en.wikipedia.org/wiki/FGM-148_Javelin) hand missile launcher which does a short jump before igniting its engines proper. This is to mask the heat signature to limit the possibility of return fire. ---
**Author:** ![kombatminipig](https://avatars.discourse-cdn.com/v4/letter/k/b5ac83/32.png) [@kombatminipig](https://boards.straightdope.com/u/kombatminipig)\ **Post date:** [March 30, 2012, 12:46pm UTC](https://boards.straightdope.com/t/ship-launches-missile-that-goes-underwater-before-ignition-but-why/617057/24 "2012-03-30T12:46:49Z")
> [@SunSandSuffering](#): > > It kind of reminds me of the [Javelin](http://en.wikipedia.org/wiki/FGM-148_Javelin) hand missile launcher which does a short jump before igniting its engines proper. This is to mask the heat signature to limit the possibility of return fire. Hm, no…not really. The initial ‘soft’ booster is to get the missile out of the way of the operator before the engine proper fires. Otherwise the operator would be at risk of the backblast from the launch if the missile was fired from any enclosed space. In fact, it says exactly that in your source. The booster’s effect on denying return fire is unexistant. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [March 30, 2012, 4:45pm UTC](https://boards.straightdope.com/t/ship-launches-missile-that-goes-underwater-before-ignition-but-why/617057/25 "2012-03-30T16:45:56Z")
> [@kombatminipig](#): > > Hm, no…not really. The initial ‘soft’ booster is to get the missile out of the way of the operator before the engine proper fires. Otherwise the operator would be at risk of the backblast from the launch if the missile was fired from any enclosed space. **kombatminipig** is right. The _Javelin_ is an awesome weapon, but without the “soft” booster it might be _face-meltingly_ awesome…literally. > [@kombatminipig](#): > > The booster’s effect on denying return fire is unexistant. At the risk of angering miniature combatant pigs armed with missiles (_[Javelinas](http://en.wikipedia.org/wiki/Javelina)_, I assume) I’ll add that the word “unexistant” appears to be nonexistent. 😉 ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [March 30, 2012, 4:58pm UTC](https://boards.straightdope.com/t/ship-launches-missile-that-goes-underwater-before-ignition-but-why/617057/26 "2012-03-30T16:58:07Z")
Nonsense, it’s a perfectly cromulent word. ---
**Author:** ![kombatminipig](https://avatars.discourse-cdn.com/v4/letter/k/b5ac83/32.png) [@kombatminipig](https://boards.straightdope.com/u/kombatminipig)\ **Post date:** [March 31, 2012, 12:55pm UTC](https://boards.straightdope.com/t/ship-launches-missile-that-goes-underwater-before-ignition-but-why/617057/27 "2012-03-31T12:55:57Z")
> [@Sailboat](#): > > At the risk of angering miniature combatant pigs armed with missiles (_[Javelinas](http://en.wikipedia.org/wiki/Javelina)_, I assume) I’ll add that the word “unexistant” appears to be nonexistent. 😉 The pig humbly submits and stands corrected 🙂 ETA: My god, my mind is blown by that link. [Previous page](https://boards.straightdope.com/t/ship-launches-missile-that-goes-underwater-before-ignition-but-why/617057.md?page=1)