Anti-Surface Warfare (ASuW) - Heavy Weight Torpedoes

[Nilgiri]

I think this is the only dedicated torpedo thread in the forum, so I might as well post this here...and for greater reach to members interested in subject....

Got talking lately about MSP (magnetic self protection) with an old (USN) bud (long retired).

When he served (in thick of cold war), ships of his era sometimes still had countermeasure to torpedoes in degaussing to reduce magnetic signature (w.r.t background) as far as possible.

It is my understanding this countermeasure is now largely obsolete (though he was unsure being retired so long).

I explained to him my overall understanding...paraphrasing here:

1) Torpedoes are now fairly advanced to track with sonar (passive and/or active)...and are good enough detonate under ship optimally by that alone these days.

2) System is much more accurate these days (even by themselves alone) than magnetic pistol+fuse.
i.e Loss of contact in final phase would be of minimal relevance (not enough for ship to significantly change position anyway)

3) Modern magnetic fuses (used alongside the above or independently) project own field that more than adequately make use of the relative large amount of steel (And steel's intrinsic magnetic permeability) in the ships hull to induce+detect a change in field (that can be detected no matter the "degaussing" the ship may have done)

What are your thoughts on this @Anmdt et al. (Any other navy and/or torpedo experts please weigh in as you like).

Was I more or less correct in explaining it this way to him?

A (more current) naval tech guy later told me that mk 48 has been through about 7 major upgrades and that there are still coils in the sensor pack for (supposedly) magnetic detection, but the emphasis seems to be on sonar there.

Composite (non steel) hulls (Visby etc) also counter this stuff apparently by specific compensation system (for all metal items on board) to apparently negate their field disturbances in real time....and present full magnetic "stealth" in that realm.

Wonder if you have come across this stuff? It is not my realm but it piqued my interest conceptually.

I feel it must have large relevance going forward to ULAQ and other distributed sensoring + weapon strategy (use of composite hull as extra benefit in defence...and if they will have these extra robust counters on board too size and relevance permitting).

@AlphaMike @Kartal1 @Madokafc @Cabatli_53 @T-123456 @Isa Khan @Bilal Khan(Quwa) @Test7 @Saithan @MisterLike @Gessler et al.

 

[Bogeyman]

I think this is the only dedicated torpedo thread in the forum, so I might as well post this here...and for greater reach to members interested in subject....

Got talking lately about MSP (magnetic self protection) with an old (USN) bud (long retired).

When he served (in thick of cold war), ships of his era sometimes still had countermeasure to torpedoes in degaussing to reduce magnetic signature (w.r.t background) as far as possible.

It is my understanding this countermeasure is now largely obsolete (though he was unsure being retired so long).

I explained to him my overall understanding...paraphrasing here:

1) Torpedoes are now fairly advanced to track with sonar (passive and/or active)...and are good enough detonate under ship optimally by that alone these days.

2) System is much more accurate these days (even by themselves alone) than magnetic pistol+fuse.
i.e Loss of contact in final phase would be of minimal relevance (not enough for ship to significantly change position anyway)

3) Modern magnetic fuses (used alongside the above or independently) project own field that more than adequately make use of the relative large amount of steel (And steel's intrinsic magnetic permeability) in the ships hull to induce+detect a change in field (that can be detected no matter the "degaussing" the ship may have done)

What are your thoughts on this @Anmdt et al. (Any other navy and/or torpedo experts please weigh in as you like).

Was I more or less correct in explaining it this way to him?

A (more current) naval tech guy later told me that mk 48 has been through about 7 major upgrades and that there are still coils in the sensor pack for (supposedly) magnetic detection, but the emphasis seems to be on sonar there.

Composite (non steel) hulls (Visby etc) also counter this stuff apparently by specific compensation system (for all metal items on board) to apparently negate their field disturbances in real time....and present full magnetic "stealth" in that realm.

Wonder if you have come across this stuff? It is not my realm but it piqued my interest conceptually.

I feel it must have large relevance going forward to ULAQ and other distributed sensoring + weapon strategy (use of composite hull as extra benefit in defence...and if they will have these extra robust counters on board too size and relevance permitting).

@AlphaMike @Kartal1 @Madokafc @Cabatli_53 @T-123456 @Isa Khan @Bilal Khan(Quwa) @Test7 @Saithan @MisterLike @Gessler et al.

Lighter, more efficient ships using composites​

The Russian Navy modernization initiatives for mine sweepers have led to the implementation of advanced composite manufacturing technologies. Composites are lightweight and strong, helping make ships more lightweight and fuel-efficient, while extending service life.
To build composite ships for the Russian Navy, SNSZ has completely overhauled its fiberglass production facility, purchased modern equipment and implemented advanced technologies. “We have established an unparalleled facility,” says V.A. Seredokho, director general at SNSZ. “We are capable of making extremely large and complex designs with the most advanced technologies.”
Making a large composite product such as a ship hull in an open mold is a health hazard because of the use of toxic resin for impregnation and polymerization. As a result, the company’s experts use a closed mold to make hulls. The closed mold process requires special reinforcement material (dry fabric) layup technology for use with complex hull surfaces.


To fulfill an order for the Russian Navy, SNSZ developed a one-piece composite hull more than 60-meters long and more than 8-meters high (about 1,000 tons displacement). SNSZ engineers believe that this achievement is a first and a remarkable milestone in non-metal hull production technologies.

Siemens Software customer case studies

Read Siemens Software customer case studies to learn how our customers partner with us to enhance productivity and gain a competitive advantage.

www.plm.automation.siemens.com

I think this is what you were looking for

 

[Nilgiri]

Lighter, more efficient ships using composites​

The Russian Navy modernization initiatives for mine sweepers have led to the implementation of advanced composite manufacturing technologies. Composites are lightweight and strong, helping make ships more lightweight and fuel-efficient, while extending service life.
To build composite ships for the Russian Navy, SNSZ has completely overhauled its fiberglass production facility, purchased modern equipment and implemented advanced technologies. “We have established an unparalleled facility,” says V.A. Seredokho, director general at SNSZ. “We are capable of making extremely large and complex designs with the most advanced technologies.”
Making a large composite product such as a ship hull in an open mold is a health hazard because of the use of toxic resin for impregnation and polymerization. As a result, the company’s experts use a closed mold to make hulls. The closed mold process requires special reinforcement material (dry fabric) layup technology for use with complex hull surfaces.


To fulfill an order for the Russian Navy, SNSZ developed a one-piece composite hull more than 60-meters long and more than 8-meters high (about 1,000 tons displacement). SNSZ engineers believe that this achievement is a first and a remarkable milestone in non-metal hull production technologies.

Siemens Software customer case studies

Read Siemens Software customer case studies to learn how our customers partner with us to enhance productivity and gain a competitive advantage.

www.plm.automation.siemens.com

I think this is what you were looking for

Yes the intrinsic benefits of composite hulls (and improving their manufacturing process) is explained here fairly well.

I was more wondering about the specific countermeasures on board (when the ship is of size like Visby class) to counter its own unavoidable magnetic signature (from the onboard metal bits and pieces it has unavoidably).

Apparently it projects active cancellation w.r.t its own magnetic field lines....and they are advanced enough now to do so dynamically.

It sounds to me like a pretty advanced and useful system for composite hull ships that are expected to see lot of interdiction in conflict.

 

[Anmdt]

I think this is the only dedicated torpedo thread in the forum, so I might as well post this here...and for greater reach to members interested in subject....

Got talking lately about MSP (magnetic self protection) with an old (USN) bud (long retired).

When he served (in thick of cold war), ships of his era sometimes still had countermeasure to torpedoes in degaussing to reduce magnetic signature (w.r.t background) as far as possible.

It is my understanding this countermeasure is now largely obsolete (though he was unsure being retired so long).

I explained to him my overall understanding...paraphrasing here:

1) Torpedoes are now fairly advanced to track with sonar (passive and/or active)...and are good enough detonate under ship optimally by that alone these days.

2) System is much more accurate these days (even by themselves alone) than magnetic pistol+fuse.
i.e Loss of contact in final phase would be of minimal relevance (not enough for ship to significantly change position anyway)

3) Modern magnetic fuses (used alongside the above or independently) project own field that more than adequately make use of the relative large amount of steel (And steel's intrinsic magnetic permeability) in the ships hull to induce+detect a change in field (that can be detected no matter the "degaussing" the ship may have done)

What are your thoughts on this @Anmdt et al. (Any other navy and/or torpedo experts please weigh in as you like).

Was I more or less correct in explaining it this way to him?

A (more current) naval tech guy later told me that mk 48 has been through about 7 major upgrades and that there are still coils in the sensor pack for (supposedly) magnetic detection, but the emphasis seems to be on sonar there.

Composite (non steel) hulls (Visby etc) also counter this stuff apparently by specific compensation system (for all metal items on board) to apparently negate their field disturbances in real time....and present full magnetic "stealth" in that realm.

Wonder if you have come across this stuff? It is not my realm but it piqued my interest conceptually.

I feel it must have large relevance going forward to ULAQ and other distributed sensoring + weapon strategy (use of composite hull as extra benefit in defence...and if they will have these extra robust counters on board too size and relevance permitting).

@AlphaMike @Kartal1 @Madokafc @Cabatli_53 @T-123456 @Isa Khan @Bilal Khan(Quwa) @Test7 @Saithan @MisterLike @Gessler et al.

This topic is not my expertise but i have a few guesses, trying to keep it short as possible;

- You are pretty much right about the sonars, also the data processing capabilities has remarkably increased the sonar may even evaluate the motion of a ship, track its keel and engage at a proper timing to detonate at the right depth. But Naval doctrine still relies on taking all possible measures to evade the torpedoes and missiles, including maneuvering, speeding up, changing direction etc. So de-gaussing is still there and will be there. Especially for a chance at high sea-states where keel of the vessel starts moving a bit more.

-The de-gaussing is also about the eddy current that is induced on the magnetic hulls due to the motion (in simple terms) and actually increasing the hull's effect on the earth's magnetism, detonation by magnetism of the material is as you described is about the material itself, magnetic permeability, at this point i am not sure how internal magnetic materials would cause a trigger on the torpedo's magnetic detonator. Degaussing is about "let's not make it worse than it is already".

-The composites, woodern, non-magnetic steels, aliminum hulls are mainly about the naval mines for now and applied on mine sweepers/hunters, FACs (Visby is a FAC for me, to be honest), SOF vessels. But modern mines also use acoustic signature as a reference and known to be advanced far enough to distinguish friend or foe merely by acoustic signature. But old habits die hard, even harder at the sea.

Last note: Operation wise,the vessels mentioned in #3 is mainly targeted by the naval mines, i doubt if a submarine will reveal its existence in the perimeter by launching a heavy torpedo to destroy them. Thus it makes torpedo vs non-magnetic hull duel obsolote until we are seeing whole composite or non-magnetic frigates-destroyers.

Fact: We are in 21st century where supersonic missiles are around, hypersonics are deployed, network centric warfare is booming yet manned machine guns still have this "cruise missile flight path" plate attached next to them, as if the gunner can shoot them down. This could explain the mindset of sailors.

 

[Nilgiri]

-The de-gaussing is also about the eddy current that is induced on the magnetic hulls due to the motion (in simple terms) and actually increasing the hull's effect on the earth's magnetism, detonation

Yep...we were talking about electrical stuff and transformers in another thread (the meme one)...

When you said eddy current, I remembered way back to my physics prof in high school, drawing little loop arrows in transformer "core" hehe. Part of the course how to mitigate their effect IIRC.

There of course the Alternating current is producing the inductive effect (and the eddies given the relative volume of iron core).

Its the larger faraday et al. principle of moving stuff among stuff (that have magnetic fields)....so you are spot on its the ships movement versus the global earth field causing the phenomenon of interest for a magnetic pistol+fuse to operate on (and however they have all advanced and counter-advanced to the modern day).

This also explains with increased sensitivity (of the sensors), the torpedo itself able to measure its own generated induction on the hull as it approaches the target....it is essentially very much like the needle that faraday moved towards metal coil...and noticed EMF spike generated.

I guess this all is programmed optimally as to intial guidance and terminal guidance depending on the relevant ranges/precision involved from the magnetic side (ship/earth frame of reference vis a vis torpedo/ship frame of reference magnetic field change wise etc)

Anyway you have more or less further confirmed some other things we got talking about casually....thanks buddy!

 

[Nilgiri]

Some physics talk on this page @Yasar @VCheng @Gautam (and other science/engg guys I forgot to tag, sorry)....might be interested to read. #51 onwards..

 

[VCheng]

A (more current) naval tech guy later told me that mk 48 has been through about 7 major upgrades and that there are still coils in the sensor pack for (supposedly) magnetic detection, but the emphasis seems to be on sonar there.

Composite (non steel) hulls (Visby etc) also counter this stuff apparently by specific compensation system (for all metal items on board) to apparently negate their field disturbances in real time....and present full magnetic "stealth" in that realm.

Wonder if you have come across this stuff? It is not my realm but it piqued my interest conceptually.

Some basic background on this topic:

Degaussing — National Museum of the Royal New Zealand Navy

The degaussing system is installed aboard ship to reduce the ship's effect on the Earth's magnetic field.Because of its distortion effects on the Earth’s magnetic field, the ship can act as a trigger device for magnetic sensitive ordnance or devices which are designed to detect these distortions.

navymuseum.co.nz

Reducing the Magnetic Signature of a Submarine

The contrast in permeability between a submarine

www.comsol.com

Much of the state of the art in hiding such magnetic signatures is currently classified.