Basic ASW Tactics

[Madman_GNSF]

For the record - I use active sonar ALL THE TIME against human controlled subs - and my world never comes crashing down.

People are to scared to use it...All it gives away is your bearing - the same info you get from sonar (just doesn't continue after pinging has stopped). Best of all - if you get a return - you get the enemies exact location - in exchange for only your bearing.

Although I only use it against submarines that are human controlled :-)

[SeaQueen]

Using active sonar makes sense especially if your sonar range is in all likelyhood less than your opponent's. The reason is that the excess range gives him the time to develop a solution while you haven't detected him. If he closes, you won't have the time to develop an equivilent solution so it's best to just ping.

Originally Posted by Madman_GNSF

For the record - I use active sonar ALL THE TIME against human controlled subs - and my world never comes crashing down.

People are to scared to use it...All it gives away is your bearing - the same info you get from sonar (just doesn't continue after pinging has stopped). Best of all - if you get a return - you get the enemies exact location - in exchange for only your bearing.

Although I only use it against submarines that are human controlled :-)

[Molon Labe]

I'll use a sub's active sonar in two situations. First, if I'm hunting a Kilo--active detection range is greater than passive against a Kilo, and it is often greater than the maximum range of the Klub-ASW's. Yeah, I know, not very sporting, but it's something I started doing to counter the Kilo BB cheat.) The other situation is when I know my opponent has already detected me and probably has a solution. In that situation, a ping from me only evens the score.

In my experience, though, many people who use active sonar tend to use it too often. There have been many cases where I didn't have a good solution on my opponent but it firmed up real quick when they started pinging away.

[kage]

Originally Posted by SeaQueen

Search tactics for ASW and search tactics for search and rescue are basically the same ideas.

Except that if the target should detect you first, he may maneuver...

This makes some search tactics less useful than others. A ladder or barrier search, for example, means that he can wait, and then run past on one side as you're pretty much on the other side of the ladder.

[SeaQueen]

Originally Posted by kage

Except that if the target should detect you first, he may maneuver...

This makes some search tactics less useful than others. A ladder or barrier search, for example, means that he can wait, and then run past on one side as you're pretty much on the other side of the ladder.

That's true. One of the shortcommings of the mathematical formulation of search theory is that it assumes that you're using passive sensors and the target won't do strange things to evade detection. Those assumptions are pretty good so long as your sensor range is longer than your target's, but if it's shorter than your target's or even just comparable to your target's, the possiblity of the target adopting specific evasive tactics becomes possible.

That's why it's good to have a sensor advantage.

[LoBlo]

Originally Posted by SeaQueen

It depends on which type of quick mission you're performing. Is it the "area search" or is the "barrier search." If it's the "area search" then you want to plot a course through the area such that the area covered by your primary search sensor (usually your towed array) is equal to the size of the area. Usually you can do this by driving a ladder pattern. The spacing of the various waypoints depends on how far you think you can see. You can guestimate it from experience or you can do what I do, and use the mission editor. If you look in missions I design, I actually try to include that information as part of the briefing.

It doesn't really matter much what you do when you're in the box, statistically, though, because complicating factors such as target motion, maneuvering for TMA, flight ops, and unmasking weapons, means that you the area covered will almost always overlap itself a little bit no matter how carefully you plan the search. That has the effect of making almost every search equivilent to random searching. The formula for the cumulative probability of detection as a function of time is given by the Koopman random search equation.

Pd = 1-exp(-2R v t / A)

where R is the sensor range, v is your speed, t is time, and A is the size of the area you are searching. It's just the exponential distribution. You can find detailed derivations of it in Wagner's Naval Operations Analysis, or Koopman's Search and Screening. You might also be able to find it in SAR manuals. Search tactics for ASW and search tactics for search and rescue are basically the same ideas. You want to find something where you have only a rough idea of it's location as efficiently as possible. From that you should be able to make a pretty good estimate of how long it'll take you to find him, on average.

For the case of the barrier quick mission, you just need to drive back and fourth between the two waypoints. The probability of you succeeding in detecting a target depends on your speed, your sensor range, the length of the barrier and the target's speed. In the literature I just mentioned, they give formulas for the Pd of barriers as well. By making assumptions about the target's speed and your sensor range, you can often optimize your speed to maximize your probablity of detection, given the constraint of wanting to minimize your noise level.

Checking your baffles isn't necessarily the first thing you do, but it can't hurt. I actually have a random number generator in an Excel spreadsheet, to generate things like random times and bearings, so that I don't get too predictable. Some people do it regularly. One of the good things about your towed array, though, is that it gives you pretty good coverage of every place but the endfire forward. The baffles clearing thing is mostly an issue with submarines that lack a towed array.

Nice! Thanks