Feasibility: Ship reactive armour?

[Tuck]

Just hit me today, looking at some in-progress pics of a 1/350 Saratoga.  I thought to myself, man what a broadside target for torpedoes.  Then I though, well, what about reactive armour for the hull?  Would it be possible to reduce the impact of the torpedo explosive charge, or would the explosion of the reactive armour do just as much pressure wave damage as the torpedo itself?



Tuck

[deathjester]

ERA uses a shaped charge, directing the force of the blast away from the hull, so I think it could well work.  What might work even better would be something similar to claymore mines attached to the hull,which would throw out small explosive charges when a torpedo comes close.  The only problem I can see would be one of drag.  Other than that, a good idea!!
The other way to defeat a torpedo would be to have a hydrofoil warship, which would actually be faster than the torpedo chasing it!

[pyro-manic]

I don't think it would be feasible. Reactive armour works by disrupting the plasma jet created by a shaped-charge warhead. Modern torpedoes have rather heavy payloads - the British Spearfish, for example, has a 300kg warhead - which would create a very large jet. This is designed to penetrate the hulls of submarines. To disrupt this, a very large ERA charge would be needed. Against surface ships, the torpedo actually detonates under the hull, which causes massive damage (it basically breaks the ship in half). See here for the kind of effect it has. In this case, the damage is done by the pressure wave and the hull itself flexing as a result, against which ERA would have no effect. In any case, I think detonating explosives on the hull of any ship is a bad idea.

[deathjester]

Exactly!  Perhaps a semi active point defence micro-torpedo system is the answer?

[pyro-manic]

I believe something of the sort is currently being developed.

[jcf]

Bulges and water filled torpedo belts are the classic means of passive defense.

Perhaps expand the concept to a full double-hull design filling the space with some sort of shock absorbing gel
or foam and spaced ceramic plates to disperse the warhead blast?

Of course the best torpedo defense is to prevent the launch. 

Jon

[Gary]

Of course the best torpedo defense is to prevent the launch. 

Jon
[/quote]


Are you talking about peace? Cripes, how much fun would that be?

Dang Hippy!

[Joe C-P]

Reactive armor underwater would only cause more damage to the ship. Water is basically incompressible, so any blast would be directed into the ship.

Multiple hulls with voids between, some empty, some containing water and/or liquid fuel, are the second best defense against underwater explosions. The best defense, albeit not always possible due to excellent quieting and rules of engagement, is to sink said sub before it shoots.
Above water there is simply too much surface area to consider using reactive armor. SSMs will often rise and dive onto a ship, trying to fool defenses while also directing the blast downward as much as inward. Again, active defenses of missiles and rapid-fire guns are more effective than absorbing the blow.

JoeP

[lenny100]

Most modern torpedo's do not hit the ship anymore.

They are designed to blow up under the hull causing a vacuum bubble under the hull of the ship which bends the keel down then as it collapses the wight of water pusses the keel up again snapping most small warships in two and damaging most large warships

see here you can actualy see this happing

www.metacafe.com/watch/1248124/torpedo_hits_battleship

this means all reactive armour is  useless

[ChernayaAkula]

So, with no proper means against torpedoes and increasing CIWS-capabilities against ASMs, how about an ASM that drops a torpedo a few klicks short of the target? Speed and stand-off capability of the ASM, deadliness of the torpedo!

[pyro-manic]

Was thinking about that recently. Possibly a modified ASROC or Ikara? You might have to make the whole thing bigger, though - these weapons both carry lightweight torpedoes, which have much smaller warheads. Range would also need to be improved.

[deathjester]

Was thinking about that recently. Possibly a modified ASROC or Ikara? You might have to make the whole thing bigger, though - these weapons both carry lightweight torpedoes, which have much smaller warheads. Range would also need to be improved.

How about a version of the Tomahawk cruise missile, then subs could carry it as a standoff weapon.

[Gary]

Question, what sets off a torpedo as it passes under a ship? Magnetic fields? Sound? Some form or remote detonation as in wire guidance? Kamakazie Hamsters? If you could figure out what causes the Earth shattering kaboom, could you make something to set off the Earth Shattering Kaboom while it's far enough away to not cause a boo boo?

I know there were aircraft with hula hoops that were flying around setting off magnetic mines during WW2. What, did someone forget how to do that?

It seems to me that when a torpedo is fired it's something that can be heard. You likely can sort out the direction as well. How about a very very low yield nuke round in say a three in mount, swivel and fire in that direction. You don't need to be overly accurate, just get the shell under the water 20 feet or so in front of the torpedo and kablewie.

Now before you say NUKE! think a moment. Aren't most torpedos meant to sink a US carrier nuke tipped? We typically depend on accuracy while others have historically depended on a whacking great kaboom. So you replace a small nuke for the bigger one, and your carrier is still floating.

You know...
peace is looking better and better

[GTX]

Exactly!  Perhaps a semi active point defence micro-torpedo system is the answer?

Already in existence:



Regards,

Greg

[B777LR]

Another few reasons reactive armour might not work.
1. It would get wet. Not just rain, or a quick soaking, but being submerged for years at a time. How does reactive armour work when it has soaked water?

2. While it works on a tank, modern warships have almost no armour, if any at all. There is a risk that the reactive armour might actually blow wholes in the ship itself...