Thank you for your explanations. Can you also determine how long they will last and what about their battery life as well. I know that it would take allot of energy to power a mine like that as well as the torpedo itself when it is sent on its way. So just how long do batteries last on this type of equipment?
I personally have no idea. Other then the description of the mine and how it works there is fairly little information on it's specific operation. I think my explanation is the most accurate simply because it would make sense.
But the actual mechanisms inside of the casing are not apparent to me. I can give you a few guesstimations.
The primary example of such a mine is the US MK 60 CAPTOR which stands for enCAPsulated TORpedo.
My best guess is that it can depend. You don't need much electricity to power the crude sonar array due to it's passive nature. And it can really depend on the complexity of the computer.
You need a computer to process the data from the passive sensor. That would imply that the computer would have to be on 24/7. It needs to be able to identify target tracks.
You rarely constantly detect an enemy sub on passive, more often you detect them once on a certain bearing, create a "target track", a line from where you were at detection to the bearing. Passive can't tell you the range of a vessel, it can be a very fast vessel at 10nm or a slow vessel at 1 nm. When you detect another passive signature very close to the original bearing (within a degree or so) you create another track and put the two together. By figuring out the class of ship based on sound you can obtain the number of prop blades, then the speed of it. With some geometry you can roughly estimate the course and distance. The faster a submarine crew can do these is the more accurate, because all of these factors especially distance and bearing are time sensitive.
Once you get bearing, course, and speed you can usually get a good enough targeting solution for firing. But for anti submarine warfare you usually want depth.
Now, as I said before, this mine might actually be a lot less sophisticated then this. It could be as simple as, a sonar array hooked to a computer. When the computer can accurately determine the class of submarine then it fires the torpedo with what I call a "blind solution".
I blind solution is basically that you suspect a submarine is in a certain location, but you don't know for sure. You see, there are two detection patterns for the average torpedo. Snake and circle. Snake looks like...a snake weaving back and forth, that way the active array can cover a large area as its travelling, once it obtains lock it stops weaving and takes the shortest route.
This is used when you have an accurate solution and there is room for error.
When you are blind firing you set it to circle. When the torpedo reaches a set distance it activates the active sonar and starts pinging away while maintaining a circular path so it covers 360 degrees with its sonar.
My assumption was that the CAPTOR was made to obtain an accurate solution, the advantage is that the torpedo has vastly increased range.
But it could be as simple as:
1. Submarine passes very close.
2. CAPTOR computer identifies hostile submarine.
3. Computer activates the torpedo's computer which has a preset blind solution.
4. Steam ejects the torpedo from the casing and the torpedo engages the motor.
5. Torpedo reaches activation depth and proceeds to begin a circular detection path and starts pinging away with the active sonar.
6. Torpedo obtains target and gives chase.
You see, the difference between that and my other explanation is that my other explanation assumes that the CAPTOR would create an actual targeting solution for the torpedo based on the target. This above one has a solution that assumes that the submarine is close enough to the mine that the torpedo will obtain it on it's own without an accurate target solution.
The reason why my first explanation would have extended range is because the torpedo in the simple version never leaves the area around the casing while searching for the sub. With an accurate solution it could leave that immediate area before starting to bang away with it's active sonar.
I think that a CAPTOR's longevity would only be determined by the electrical usage of it's computer. A computer that plots a target solution uses vastly more electricity then a computer that is nothing more then a trip wire with a pressurized gas container with a torpedo strapped to it.