CM-400AKG: Pakistan's supersonic carrier killer

[Penguin]

So that does bear out my point, anyway.

whatever...

 

[Capt.Popeye]

whatever...

Yes of course, whatever...

 

[Penguin]

Also keep in mind that, although subs were frequently involved in actually sinking carriers, often the carrier was first damaged/disabled by air or surface attack. Thus slowed down, (conventional) subs could then catch the carrier. This remains relevant today, as the majority of navies operating subs do not operate nuclear subs.

Also, a high mach high diving missile might succeed in penetrating all decks (CVF e.g. 9 decks) and breach the hull bottom, or explode there where aviation and ship stores are located (cause further explosions there, near the hull bottom, very much below the waterline). You'ld need a penetrating warhead. Ships are relatively hard targets and usually require a kinetic energy penetrating warhead, followed by blast fragmentation after penetration of the hull. Consequently, anti-ship missiles are generally large size and have a large warhead.

 

[S.Y.A]

So that does bear out my point, anyway.

can a torpedo damage propellers of aircraft carrier, and thus slow it down?

 

[Capt.Popeye]

can a torpedo damage propellers of aircraft carrier, and thus slow it down?

Oh yes, even the Rudder(s) can be damaged.

 

[S.Y.A]

Oh yes, even the Rudder(s) can be damaged.

but still an aircraft carrier is large ship and a torpedo is well tiny as compared to it

 

[Capt.Popeye]

but still an aircraft carrier is large ship and a torpedo is well tiny as compared to it

It depends on the number of hit(s) by torpedos and where (and how strong/magnitude) the hit(s) are.
Other wise, the warhead of a torpedo is small wrt the size of a Carrier. Ditto for a Missile.

 

[Penguin]

can a torpedo damage propellers of aircraft carrier, and thus slow it down?

Tom Clancy Debt of Honor (story: during a joint military exercise, Japanese ships "accidentally" launch torpedoes at the U.S. Pacific Fleet, destroying two submarines and crippling two aircraft carriers, the Enterprise and the John C. Stennis. This drastically reduces the U.S. capability to project power into the western Pacific)?

The homing systems for torpedoes are generally acoustic, though there are other target sensor types. Acoustic homing formed the basis for torpedo guidance after the Second World War. Homing "fire and forget" torpedoes can use passive or active guidance, or a combination of both. Passive acoustic torpedoes home in on emissions from a target. Active acoustic torpedoes home in on the reflection of a signal, or "ping", from the torpedo or its parent vehicle; this has the disadvantage of giving away the presence of the torpedo. In semi-active mode, a torpedo can be fired to the last known position or calculated position of a target, which is then acoustically illuminated ("pinged") once the torpedo is within attack range. A ship's acoustic signature is not the only emission a torpedo can home in on. Wake homing torpedoes were first developed during WW2. Specifically to engage U.S. supercarriers, the Soviet Union developed the 53-65 wake-homing torpedo. The 53-65 became operational in 1965, while the 53-65K and 53-65M both became operational in 1969. The 53-65KE is an exported version. The Type 53 torpedo is carried by almost all Russian submarines.

 

[Penguin]

13.4.1 Blast Warheads

A blast warhead is one that is designed to achieve target damage primarily from blast effect. When a high explosive detonates, it is converted almost instantly into a gas at very high pressure and temperature. Under the pressure of the gases thus generated, the weapon case expands and breaks into fragments. The air surrounding the casing is compressed and a shock (blast) wave is transmitted into it. Typical initial values for a high-explosive weapon are 200 kilobars of pressure (1 bar = 1 atmosphere) and 5,000 degrees celsius.

The shock wave generated by the explosion is a compression wave, in which the pressure rises from atmospheric pressure to peak overpressure in a fraction of a microsecond. It is followed by a much slower (hundredths of a second) decline to atmospheric pressure. This portion is known as the positive phase of the shock wave. The pressure continues to decline to subatmospheric pressure and then returns to normal. This portion is called the negative or suction phase. A pressure-time curve is shown in figure 13-4. The durations of these two phases are referred to as the positive and negative durations. The area under the pressure-time curve during the positive phase represents the positive impulse, and that during the negative phase, the nega- tive impulse. The result of this positive/negative pressure var- iation is a push-pull effect upon the target, which causes tar- gets with large volume to effectively explode from the internal pressure.

For a fixed-weight explosive, the peak pressure and positive impulse decrease with distance from the explosion. This is due to the attentuation of the blast wave. The rate of attenuation is proportional to the rate of expansion of the volume of gases behind the blast wave. In other words the blast pressure is in-versely proportional to the cube of the distance from the blast center (1/R3). Blast attenuation is somewhat less than this in-side, approximately 16 charge radii from blast center. It should also be noted that there will be fragmentation when the warhead casing ruptures.

13.4.1.2 Underwater Blast Warheads. The mechanism of an under-water blast presents some interesting phenomena associated with a more dense medium than air. An underwater explosion creates a cavity filled with high-pressure gas, which pushed the water out radially against the opposing external hydrostatic pressure. At the instant of explosion, a certain amount of gas is instantan-eously generated at high pressure and temperature, creating a bubble. In addition, the heat causes a certain amount of water to vaporize, adding to the volume of the bubble. This action immediately begins to force the water in contact with the blast front in an outward direction. The potential energy initially possessed by the gas bubble by virtue of its pressure is thus gradually communicated to the water in the form of kinetic ener-gy. The inertia of the water causes the bubble to overshoot the point at which its internal pressure is equal to the external pressure of the water. The bubble then becomes rarefied, and its radial motion is brought to rest. The external pressure now com-presses the rarefied bubble. Again, the equilibrium configura-tion is overshot, and since by hypothesis there has been no loss of energy, the bubble comes to rest at the same pressure and vol-ume as at the moment of explosion (in practice, of course, energy is lost by acoustical and heat radiation).

The bubble of compressed gas then expands again, and the cycle is repeated. The result is a pulsating bubble of gas slow-ly rising to the surface, with each expansion of the bubble creating shock wave. Approximately 90% of the bubble's energy is dissipated after the first expansion and contraction. This phen-omenon explains how an underwater explosion appears to be fol-lowed by other explosions. The time interval of the energy being returned to the bubble (the period of pulsations) varies with the intensity of the initial explosion.

The rapid expansion of the gas bubble formed by an explo-sion under water results in a shock wave being sent out through the water in all directions. The shock wave is similar in gener-al form to that in air, although if differs in detail. Just as in air, there is a sharp rise in overpressure at the shock front. However, in water, the peak overpressure does not fall off as rapidly with distance as it does in air. Hence, the peak values in water are much higher than those at the same distance from an equal explosion in air. The velocity of sound in water is nearly one mile per second, almost five times as great as in air. Con-sequently, the duration of the shock wave developed is shorter than in air.

The close proximity of the upper and lower boundaries between which the shock wave is forced to travel (water surface and ocean floor) causes complex shock-wave patterns to occur as a result of reflection and rarefaction. Also, in addition to the initial shock wave that results from the initial gas bubble expansion, subsequent shock waves are produced by bubble pulsation. The pulsating shock wave is of lower magnitude and of longer duration than the initial shock wave.

Another interesting phenomenon of an underwater blast is surface cutoff. At the surface, the shock wave moving through the water meets a much less dense medium--air. As a result, a reflected wave is sent back into the water, but this is a rarefaction or suction wave. At a point below the surface, the combination of the reflected suction wave with the direct incident wave produces a sharp decrease in the water shock pressure. This is surface cutoff. The variation of the shock overpressure with time after the explosion at a point underwater not too far from the surface is illustrated in figure 13-6.

After the lapse of a short interval, which is the time required for the shock wave to travel from the explosion to the given location, the overpressure rises suddenly due to the arrival of the shock front. Then, for a period of time, the pressure decreases steadily, as in air. Soon thereafter, the arrival of the reflected suction wave from the surface causes the pressure to drop sharply, even below the normal (hydrostatic) pressure of the water. This negative pressure phase is of short duration and can result in decrease in the extent of damage sustained by the target. The time interval between the arrival of the direct shock wave at a particular location (or target) in the water and that of the cutoff, signaling the arrival of the reflected wave, depends upon the depth of burst, the depth of the target, and the distance from the burst point to the target. It can generally be said that a depth bomb should be detonated at or below the target and that a target is less vulnerable near the surface.

13.4.5 Special-Purpose Warheads

There are other means of attacking targets than with blast, frag-mentation, shaped charge, or continuous rod payloads. Several types of payloads are more specialized in nature, designed to perform a specific function. A few of these will be described.

13.4.5.8 Mines--Mine warheads use the underwater blast princip-les described earlier to inflict damage on the target ship or submarine. The damage energy transmitted is approximately equal-ly divided between the initial shock wave and the expanding gas bubble. If the target is straddling the gas bubble, then it will have unequal support and may be broken in two. As the detonation depth increases, particularly in excess of 180 feet, the effect of the gas bubble causing damage is greatly diminished; there-fore, bottom mines are rarely used in waters exceeding 180-200 feet. Mines typically use the highest potential explosives, gen-erally 1.3 to 175 relative strength. Captor mines have also been developed that actually launch a smart torpedo that then passive-ly and actively homes in on the target before detonation.

13.4.5.9 Torpedoes--Torpedo warheads must be capable of damaging both ships and submarines. Homing in on the screws can achieve a mobility kill. Detonation under the keel at midships can cause the severe gas-bubble damage mentioned with mines, and if the depth is less than 300 feet, the reflected shock wave can sub-stantially increase the damage effects. Torpedoes that actually impact the hull of a ship or submarine have to overcome the doub-le hull/void structure. Deep-diving submarines with especially thick hulls require highly specialized warheads. Shaped charge warheads are envisioned as the solution to this problem.

Chapter 13 WARHEADS

 

[Penguin]

The Mk48 can be guided by a wire that reels out behind it, or it can find the target by itself. Once it gets close enough to the target, it first uses sonar to aim for the centre of the ship. When it's really close, it uses the magnetic signature of the target as a trigger to explode, when it's about 15 metres directly under its hull. The depth and location are quite critical. The 267 kg of high explosive almost instantaneously all turn into a huge volume of gas.

First, the actual explosion generates a very high pressure shock wave. This rams into the middle of the underside of hull of the ship at about 1.5 kilometres per second.

Second, the shock wave crushes the underside of the hull, and also lifts it up. It bends the ship bend upward in the middle, like a banana. The upper decks of the ship crack apart. After a few hundredths of a second, the shock wave has come and gone. But within a few more fractions of a second, the expanding bubble of gas from the explosion then hits the underside of the hull. The bubble reaches a maximum size of about 18 metres across, and it maintains the massive upward force on the bottom of the hull, once the shock wave has passed. So the ship is bent upwards in the middle in two stages - from the shock wave and then the expanding gas.

Third, after about half-a-second, the bubble (thanks to some fancy physics) begins to shrink. The ship then "sags" in the middle, and begins to "banana" in the other direction. This breaks the hull of the ship even more. Navy people call this sagging the "whipping" phase. It's actually very "useful" in breaking the back of a ship - after all, if you want to break a stick, it's much more effective to bend it back-and-forth, rather than bend it in only one direction.

Fourth, after about one second, the shrinking bubble has reached its minimum size, and begins to expand again. The water pressure around it is greatest directly underneath (being further from the surface) and least at the top (being closest to the surface). So it tends to expand upwards more than downwards - in fact, it pushes a lot of water upwards as a high-speed wall of water. This "bananas" the ship back in the first direction again.

Finally, the wall of water and the enormous bubble ram right through the hull. Combined, they can be powerful enough to completely rip the superstructure (that is, everything above the hull) clean off the ship, giving the appearance of a second explosion. The hull is often snapped into two separate halves.

...

But it would all be very different if the torpedo slammed into the hull of the ship, and then exploded.

A ship in battle mode makes all its separate compartments watertight by shutting all the doors. The damage would be immense in a few compartments, which would get flooded. But the ship would probably keep on floating, with a severe list to one side. The remaining crew could be evacuated, and the ship could even possibly be repaired.

So while a missile kills a ship by going "Bang" on the body of the ship, a modern torpedo kills a ship by going "Bang" underneath it.

Torpedo hit › Dr Karl's Great Moments In Science (ABC Science)

When it comes do dealing with surface ships, many torpedoes these days don't actually hit. A standoff detonation under the keel enhances blast effects against surface ships through the amplification of stress resulting from the interaction of the explosion's products and the flexible structure of the ship. Take RN Spearfish: it has a powerful blast warhead, triggered by either contact detonation (against a submarine hull) or an acoustic proximity fuze (for under-keel detonation against ships). And I don't see a 267 kg (or even the subsonic 3M54E1 Club AShM's 400kg) missile warhead doing this kind of damage....

 

[Viper0011.]

can a torpedo damage propellers of aircraft carrier, and thus slow it down?

In today's sensor rich and integrated battle management environment, it is silly to think that there will be only 1 warhead penetrating the ship. Some missiles will be used to use fool the defensive systems and sensors. The rest of the missiles will include the heavier war heads after the defensive mechanisms have been overwhelmed. So imagine a few missiles at the least penetrating the hull. Even in the case of Torpedos, it'll be two at the least.

 

[Penguin]

Nice photo (USS Saratoga @ Bikini)

.

 

[Armstrong]

So @Penguin do you think a midget submarine could get within 2-3 miles of an Air Craft Carrier & fire away the sole, purpose-build torpedo that it carries ?

This would of course would be in case of a blockade denial role as opposed to playing catch up to an Air Craft Carrier !

 

[Penguin]

So @Penguin do you think a midget submarine could get within 2-3 miles of an Air Craft Carrier & fire away the sole, purpose-build torpedo that it carries ?

This would of course would be in case of a blockade denial role as opposed to playing catch up to an Air Craft Carrier !

Can't rule the possibility out but I figure only in the shallows plus only in places where for one reason or another a carrier can't avoid the shallows. You'ld have to be totally silent, virtually stationary, and lucky enough for the carrier to pass nearby (might as well use advanced mines in this case, since those are much smaller and don't require people.)

 

[nangyale]

It will be quite difficult for a single missile to sink a whole aircraft carrier. Might make more sense if that missile is nuclear tipped but otherwise a difficult feat to accomplish.
In real world when it is not just an aircraft carrier but a battle group that you are facing, then the strike has to be multi-front, meaning aircrafts surface ships and submarines. Using a variety of missiles and torpedoes to do the job.