Crazy Ivan maneuver in Red Storm Rising

[Abraham Gubler]

I'm not sure if the Swedes still operate land based torpedo tubes as part of a coastal defence newtwork.

All of the Swedish coastal defences have been disposed off. But shore launched torpedos was not a system they used. The Norwegians did. The Norweigan systems have been closed down as well. Both countries do maintain some coastal defence via Hellfire missile launchers moved from coast to coast in CB90 combat boats.

The basis of the Swedish coastal defences was fixed mines controlled by shore based observation points. As an enemy ship passed over the area of a mine a Swede in a bunker would press the right button and boom. The Swedish coastal guns were to defend the minefields from enemy minehunters. This system aligned to their geography which was island archipelagos in shallow water outside major population centres.

The Norwegians with deep Fjords couldn’t rely as heavily on fixed surface mines as the Swedes but because of the bottleneck each Fjord made could cover them with torpedos. They also used heavier guns to try and sink assault ships as they passed up the Fjords. The torpedoes were quite old WWII wire guided German (G-7a) and straight running British (Mk 8) but were upgraded in the 90s with Swedish Type 613s right before they were disposed of.

 

[Volkodav]

All of the Swedish coastal defences have been disposed off. But shore launched torpedos was not a system they used. The Norwegians did. The Norweigan systems have been closed down as well. Both countries do maintain some coastal defence via Hellfire missile launchers moved from coast to coast in CB90 combat boats.

The basis of the Swedish coastal defences was fixed mines controlled by shore based observation points. As an enemy ship passed over the area of a mine a Swede in a bunker would press the right button and boom. The Swedish coastal guns were to defend the minefields from enemy minehunters. This system aligned to their geography which was island archipelagos in shallow water outside major population centres.

The Norwegians with deep Fjords couldn’t rely as heavily on fixed surface mines as the Swedes but because of the bottleneck each Fjord made could cover them with torpedos. They also used heavier guns to try and sink assault ships as they passed up the Fjords. The torpedoes were quite old WWII wire guided German (G-7a) and straight running British (Mk 8) but were upgraded in the 90s with Swedish Type 613s right before they were disposed of.

Any idea what the Noregians used to sink the Blucher, it was a shore based torpedo but must have been an even older type. In fact come to think of it has any warship ever been sunk by a modern torpedo ( other than in tests or sinkex's etc) evey case I have heard of used WWII generation weapons.

 

[StingrayOZ]

In fact come to think of it has any warship ever been sunk by a modern torpedo ( other than in tests or sinkex's etc) evey case I have heard of used WWII generation weapons.

I think your right, in the Faulklands the RN I think fired unguided from the SSN's.Im trying to think of a situations where someone with modern kit was firing torps. Unless you count accidents like Kursk.

 

[Abraham Gubler]

Any idea what the Noregians used to sink the Blucher, it was a shore based torpedo but must have been an even older type. In fact come to think of it has any warship ever been sunk by a modern torpedo ( other than in tests or sinkex's etc) evey case I have heard of used WWII generation weapons.

The Blucher was sunk by a combination of heavy (280mm) and medium gun (150mm) fire and very old 'original' Whitehead torpedos. The kind of technology that popularised the weapon in the 19th century. It only spent a short period of time under fire and sunk almost two hours after the hits as the crew couldn’t contain all the fires and flooding. So very much a combined effort from the different Norweigan batteries.

The lack of ship kills from modern torpedos is more to do with lack of opportunity. AFAIK the only use of a 'modern' torpedo (successfully) was the 550mm E15 used by Pakistani submarine Hangor to sink the Indian frigate Khukri. Though in the same engagement this submarine fired two other torpedos at another Indian frigate without success. The E15 is basically a development of the WWII German T-5 Zaunkönig 1 (GNAT) that homes in on 24.5 kHz propeller cavitation noise.

 

[My2Cents]

Although it is not discussed, I would be certain that there would be arrays of hydophones off navy bases as a way of keeping an ear out for unwelcome company. Would seem a cost effective way of keeping the inner realm secure. I would imagine that there are also arrays at certain choke points, or places of high strategic value, like the persian gulf, red sea, Kuril Islands, straights of Hormus, entracnce to the black sea. etc etc

It was mentioned. Not discussed much because everyone can agree on the need I suspect.

The most likely defenses start with SOSUS (Sound Surveillance System), a fixed passive listening array, operating in conjunction with shore bases helo/airborne ASW. Next may be some surface ASW built on Coast Guard and other vessels of opportunity (trawlers, tugs, etc.) working the near (<100km) defense. Finally you have regular Navy ASW assets even farther out. Conventional submarines might be used, but could be more of a distraction to the rest of the forces than an asset.

 

[vivtho]

I think your right, in the Faulklands the RN I think fired unguided from the SSN's.Im trying to think of a situations where someone with modern kit was firing torps. Unless you count accidents like Kursk.

Yup HMS Conqueror sank the ARA General Belgrano using unguided torpedoes.

 

[Humming Drone]

What about the sinking of South Korea's Cheonan? IIRC, it is claimed to be a torpedo attack. Assuming it was a North Korean torpedo, would it be a "modern" one?

 

[Pendekar]

What's the difference between Spherical and Cylindrical array?

 

[My2Cents]

What's the difference between Spherical and Cylindrical array?

The usual -- Coverage vs. Cost. :coffee

For passive sonar applications the cylindrical array has reduced coverage in the direction centered around the axis of the cylinder. For active sonar applications these areas have no coverage. Spherical array do not have gaps (except when blocked by the supporting structure), but requires more transducers and computing power, and are therefore larger, heavier, and more expensive, for the same resolution in the arc covered.

 

[gf0012-aust]

and then there are conformal arrays. slowly evolving, but substantial potential.

 

[Pendekar]

and then there are conformal arrays. slowly evolving, but substantial potential.

So if this technology mature, i take it we don't need Fiber glass sonar dome right?

 

[gf0012-aust]

So if this technology mature, i take it we don't need Fiber glass sonar dome right?

not sure why you'd think that we no longer need bow sensors (as I assume thats what you're referring to)

the issue of conformal arrays is about being able to deal with flank arrays, or hull arrays in general. it enables complex placement, it allows sympathetic designs for a partiular hull shape, and it allows for the array to be much more signature sympathetic and thus impact on the platforms sig footprint itself over various performance parameters...

eg no more blisters = advantages in their own right.

the efficiency of the array goes up because there is a more effective distributed sensor surface area in place. think of it as an MRI in reverse...

 

[My2Cents]

So if this technology mature, i take it we don't need Fiber glass sonar dome right?

Conformal arrays are for passive not active sonar. The bow (spherical) array will need to be kept for that reason if no other.

 

[localhost127]

Conformal arrays are for passive not active sonar. The bow (spherical) array will need to be kept for that reason if no other.

ive searched but usually come up empty-handed... do you have any online articles or pdf's detailing spherical arrays? how they work? anything of that nature? i don't expect to find out much detailed information, but i would assume the basic concepts should be available somewhere. thank you -

 

[localhost127]

ok - so i've found this link which seems to provide lots of the detail i was looking for;
ES310 Introduction to Naval Weapons Engineering

one question - ive read that active sonar can approx be configured up to 250dB in water (depending on a range of factors, obviously). can active sonar then be used as a weapon to acoustically deafen or temporarily disable humans on board another submarine?

 

[My2Cents]

one question - ive read that active sonar can approx be configured up to 250dB in water (depending on a range of factors, obviously). can active sonar then be used as a weapon to acoustically deafen or temporarily disable humans on board another submarine?

dB are logarithmic. Let us assume that you need to deliver 180dB (high end for a stun grenade), so you have a 70dB budget.

Depending on the distance at which they measure the initial output, and at what frequency.

• Power level drops at the square of distance from propagation
• Power level drops exponentially from absorption and scatter, which is frequency dependant.
• The same measures that minimize sound emissions from the submarine will function to attenuate sound passing into the submarine. I’m going to give this a WAG/POOMA rating of 20dB for a WWII bare hull to 50dB to 60dB for a modern nuke with heavy acoustic tiles. The effects of the acoustic tiles will also frequency dependant, but should correspond to the peak output intensity of the sonar, doe obvious reasons.

So the equation for remaining power equals:

Delivered_dB = Original_dB – 20*log10(d/d0) – a*d – b​

where:

a = the attenuation coefficient for absorbtion/scatter
b = the hull attenuation
d = the distance to the target
d0 = the distance that the original signal strength was determined at​

Clearly this will be a (very) short range weapon. :type

 

[localhost127]

dB are logarithmic. Let us assume that you need to deliver 180dB (high end for a stun grenade), so you have a 70dB budget.

Depending on the distance at which they measure the initial output, and at what frequency.

• Power level drops at the square of distance from propagation
• Power level drops exponentially from absorption and scatter, which is frequency dependant.
• The same measures that minimize sound emissions from the submarine will function to attenuate sound passing into the submarine. I’m going to give this a WAG/POOMA rating of 20dB for a WWII bare hull to 50dB to 60dB for a modern nuke with heavy acoustic tiles. The effects of the acoustic tiles will also frequency dependant, but should correspond to the peak output intensity of the sonar, doe obvious reasons.

So the equation for remaining power equals:

Delivered_dB = Original_dB – 20*log10(d/d0) – a*d – b​

where:

a = the attenuation coefficient for absorbtion/scatter
b = the hull attenuation
d = the distance to the target
d0 = the distance that the original signal strength was determined at​

Clearly this will be a (very) short range weapon. :type

thanks

 

[Pendekar]

not sure why you'd think that we no longer need bow sensors (as I assume thats what you're referring to)

the issue of conformal arrays is about being able to deal with flank arrays, or hull arrays in general. it enables complex placement, it allows sympathetic designs for a partiular hull shape, and it allows for the array to be much more signature sympathetic and thus impact on the platforms sig footprint itself over various performance parameters...

eg no more blisters = advantages in their own right.

the efficiency of the array goes up because there is a more effective distributed sensor surface area in place. think of it as an MRI in reverse...

I think i've read somewhere that to reduce cost, The US Navy are considering to replace the Spherical array in Virginia class with some sort of conformal type sonar. I think they want to arrange the hydrophones in an array that encompass the bow of a submarine.

 

[My2Cents]

I think i've read somewhere that to reduce cost, The US Navy are considering to replace the Spherical array in Virginia class with some sort of conformal type sonar. I think they want to arrange the hydrophones in an array that encompass the bow of a submarine.

Conformal sonar is good as passive sonar but performs poorly as an active sonar due to limitations in beam formation by horizontal arrays. Unless you form a large array both vertical and horizontal on the bow and lose the cost advantage. It would give you a larger interior volume, which might be useful.

 

[STURM]

the technology was around well before 2000. one of the reasons why some countries were arcing up was that China was arguing hat they needed to protect the Beijing Olympics from acts of terrorism and were able to seek exemption from some of the european countries on dual use technology. they danced around the Tiananmen embargoes on weapons tech transfer by invoking CT issues. Cute by half

Currently reading a book about cld War naval espionage, 'Hide and Seek', co-written by a former USN officer.

According to the authors,

* The USN had dolphins trained to deal with underwater swimmers at Camh Ranh Bay. The dolphins were trained to detect intruders and force them to the surface. On their nose they had needles with poisonous gas. It seems a number of VC and Spetsnaz divers were dealt with by the dolphins in this manner.

* The Soviet navy had a facility at Sevastapol which trained sea lions and dolphins for harbour defence. After 1991, Iran bought the trained mammals and the facility was handed over to the Ukraine.

Very curious as to what the response of the sea lions and doplhins would be if confronted by a mini-sub .