French movie action drama on a SSN : Le chant du Loup (The Wolf's Call)

[Dakar23]

It's a very interesting and different movie. Very good.

[bsub]

In the movie they have some terms that are not explained.

Perhaps someone can help -

What does TUUM stand for?

What exactly are "magic points"

What is CIRA

Also -

Could an underwater swimmer survive that deep without being crushed by the weight of the water.

[jaop99]

Originally Posted by bsub

In the movie they have some terms that are not explained.

Perhaps someone can help -

What does TUUM stand for?

What exactly are "magic points"

What is CIRA

Also -

Could an underwater swimmer survive that deep without being crushed by the weight of the water.

TUUM= looks like is the modern version of the old AN/WQC-2, or Gertrude, is an underwater telephone to be used in short distances

I don't know why they need a "magic point" to launch a ballistic missile against a country that is thousand miles away, anyway, could be a place where there is no sensors, or out of satellite coverage, or something similar

I forgot the part when they use CIRA acronysm in the film

The last question is yes but almost impossible, they first equalized the external pressure, then opened the external hatch, the problem is that you can't go up quickly because you have to release the extra air in the lungs and descompress in order to avoid the extra nitrogen and inert gasses in your body, usually you can do that at less than 80 meters with stops at differents depths to avoid decompression sickness

http://www.scubadiverinfo.com/2_divetables.html

https://en.wikipedia.org/wiki/Decompression_(diving)

[Prolands]

CIRA stands for "Le centre d'interprétation et de reconnaissance acoustique", so a naval institute devoted to interpretation of acoustic signals As such the main character belongs to that unit and the top officer that scolds him after he comes ashore for wrong classification is his boss.

To answer the question about magic points:

 

It was because the boomer's captain (Grandchamp) would do things by the book and "would try to limit civilian casualties". I can only assume their target was of military nature, located next to a civilian centre of population.

Oh and TUUM is indeed an underwater telephone as Jaop mentioned, a "digital underwater communication system". It's produced by Thales, you can find the data sheet here.

[bsub]

Thanks for the answers, but I am still confused about magic points.

It seems that the captain didn't want to surface to get an exact reading of where the sub was located - I assume by GPS.

So did he go to a magic point underwater to get a bearing, or is the magic point just a point on a map that would ensure the missile had range to reach the target. I did notice that he did a scan of the ocean floor. Could you correlate that to a bearing.

[bsub]

Did some more research - it used hydrographics - a 3d scan of ocean floor and then matched results with known scan to get exact bearing - like ship ID books for the ocean floor.

Thanks again for the help.

[gumbeauregard]

I enjoyed this movie for its portrayal of the submarine and its crew.

The plot is pretty silly with some huge holes but all is forgiven for the excellent job with the crew and submarine interior scenes.

Magic points are an interesting idea. I am not sure how a boomer could know its position over sea floor terrain without using an active sensor to "look"

But then the idea that the nuclear missiles need to be launched from a precisely known position in order to be more accurate to prevent civilian casualties is a bit silly on the face of it.

The entire premise of nuclear deterrence is retaliatory strikes against the civilian population of the opponent.

[Therealmouss]

Originally Posted by bsub

In the movie they have some terms that are not explained.

Perhaps someone can help -

What does TUUM stand for?

This is the french underwater digital telephone system ( built by thales)

What exactly are "magic points"

there are just underwater navigation point, when you navigate underwater you use inertial navigation, the longer you stay below the bigger the innacurracy is, and when you launch a SLBM you need to know where you are exactly, to give you the smallest CEP on impact




What is CIRA

centre d'interprétation et de reconnaissance acoustique (CIRA)
thats where we store all accoustic signatures of all the ships, pretty secured place....

Also -

Could an underwater swimmer survive that deep without being crushed by the weight of the water.

No clue never tried :-)



The Film itself is pretty good, a few ridiculous scene ( RPG against an helicopter...) but overall good acting and good scenario

not as good as red october , but way better than hunter killer :-)

thib

[Aktungbby]

Therealmauss!

[Blaise]

Originally Posted by bsub

In the movie they have some terms that are not explained.

Perhaps someone can help -

What does TUUM stand for?

What exactly are "magic points"

What is CIRA

Also -

Could an underwater swimmer survive that deep without being crushed by the weight of the water.

The accuracy of a submarine-launched ICBM is determined by several factors, one of which is the precision to which the submarine's own position is known at the time of launch. Submarines can't detect GPS while underwater and the errors in the boat's inertial navigation system have a noticeable effect. One solution is to go to place (such as a seamount) whose position has been mapped to high precision and stored in a database in the submarine. While not necessary, the use of a 'magic point' will noticeable improve the accuracy of the missile launch.

[Aktungbby]

Blaise!

[nikimcbee]

Originally Posted by Dakar23

It's a very interesting and different movie. Very good.

Ditto. Just watched it. Very good story, totally different.

[US IRON]

RE
< Magic points are an interesting idea. I am not sure how a boomer could know its position over sea floor terrain without using an active sensor to "look">

I know zero about real world submarine navigation and I suppose it is classified, but Inertial Navigation Systems INS have been around for decades. It was standard on the 747 and other airliners before Satellite GPS. Using sensitive gyroscopes and acceleromotors (force sensors) which calculate distances, velocities and accelerations a submarine would know its position fairly accurately without need of any external references, except some initialisation point when setting the system initially and checking its accuracy. On aircraft the initialisation point on startup is the gate which is a known coordinate. Maybe they utilise magnetic fields as well?

I expect all submarines would have back-up systems like this to cross-check with other more accurate systems. I have no-idea what a magic point is.

[UglyMowgli]

Originally Posted by US IRON

RE
< Magic points are an interesting idea. I am not sure how a boomer could know its position over sea floor terrain without using an active sensor to "look">

I know zero about real world submarine navigation and I suppose it is classified, but Inertial Navigation Systems INS have been around for decades. It was standard on the 747 and other airliners before Satellite GPS. Using sensitive gyroscopes and acceleromotors (force sensors) which calculate distances, velocities and accelerations a submarine would know its position fairly accurately without need of any external references, except some initialisation point when setting the system initially and checking its accuracy. On aircraft the initialisation point on startup is the gate which is a known coordinate. Maybe they utilise magnetic fields as well?

I expect all submarines would have back-up systems like this to cross-check with other more accurate systems. I have no-idea what a magic point is.

An INS drift after some time even the laser one, what is good for an airliner flying for few hours is not for a sub navigating under the sea for months. they need to re-calibrate their position. there is few methods
- GPS but need to have a signal (and during a war, well don't count on it)
- Old sextant method, need time and like the GPS method need to be on periscope depth - too dangerous during a war/crisis


- Using a distinctive seafloor topography (a big rock in the middle of a flat) or a shipwreck whose exact location is well known. This is the magic point. And to find it, there is few systems like a XXXXX or a XXXXX - sorry this is classified


And since nobody talk about, the title of the movie Wolf call refer to the sound of an active low frequency sonar using modulation to bypass the target distance ambiguity. This sound is like a wolf howling.

[gumbeauregard]

Originally Posted by US IRON

RE
< Magic points are an interesting idea. I am not sure how a boomer could know its position over sea floor terrain without using an active sensor to "look">

I know zero about real world submarine navigation and I suppose it is classified, but Inertial Navigation Systems INS have been around for decades. It was standard on the 747 and other airliners before Satellite GPS. Using sensitive gyroscopes and acceleromotors (force sensors) which calculate distances, velocities and accelerations a submarine would know its position fairly accurately without need of any external references, except some initialisation point when setting the system initially and checking its accuracy. On aircraft the initialisation point on startup is the gate which is a known coordinate. Maybe they utilise magnetic fields as well?

I expect all submarines would have back-up systems like this to cross-check with other more accurate systems. I have no-idea what a magic point is.

I have many ocean crossings with INS as a secondary navigation system and over the few hours of a jet crossing the error is quite large. Usually 1-3 miles or so for the trip over the North Atlantic. Age and condition of the system also affect this drift.

Here are some articles I found on Gravity Anomaly Aided Inertial Navigation System (GAINS), which is pretty interesting stuff.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5579750/

https://www.navysbir.com/n09_1/N091-092.htm

https://pdfs.semanticscholar.org/860...57b0712f25.pdf

https://www.frontiersin.org/articles...019.00019/full