question about evasive manuevers

[DURUK]

ok this one goes to the hardcore skippers..
i'm playing the game with 88% difc (with map contact updates and ext view enabled) and looking forward for 100%.. however besides the handicap of calculating the target speed without the map contact update (i ussually use nomograph and 3:15) i'm really confused on how you can manage the evasive manuever and stelth combination when you don't acctually see (eighter from sonar contact or external view) that someone is passing over you and dropping charges.. any advise anyone??

at least we had the "DC in the water" warning at SH3 so that you could know when to go flank and when to remain silent.. i think they might have excluded this warning because you might not hear them dropping the DC in real but it'd be still nice to have that at least..
does anyone think that this can be modded? :hmm:

[Krupp]

I normally listen the prop sounds of attacking surface ships and the bearing for timing maneuvers and course changes. BUt currently it's almost impossible, because the sounds are biased and are coming from a 180 degree wrong direction i.e. bow is aft and left is right and vice versa. It is really confusing

Using thermal layers makes the evasing easy. I recommend the "Thermalizer" mod (or something like that) for some randomness in the layer depth (don't forget to kill the announcement sound until you have a gadget to sense those thermal layers.

[Chock]

I usually play sims on all the tough settings apart from keeping the external view (because after all that hard work I actually want to see the damn target sink )

Generally speaking, the hydrophone is a godsend for plotting interception courses and for evading the subsequent DC attack in SH3, particularly with GWX, but in SH4 I've found that it's a little less usable and doesn't seem to have the range of the one in SH3, although this could just be my perception of things. Admittedly I'm a flyer in real life, not a bubblehead, but I've done enough reading up on underwater sound propagation to surmise that it might need a bit of tweeking in SH4 to match the reality (I guess I can thank Sub Command and Dangerous Waters for forcing me to read up on all that stuff).

The thermal layer in SH4 confers good tactical advantages to subs in SH4, so choosing a position to attack is an important part of the set up - i.e. somewhere deep enough to possibly present you with a thermal layer. If this means shadowing or doing an end-around on the convoy for 50 miles, then so be it, as you'll want to load the dice in your favour as much as possible when it comes to getting away. In short, choosing your battle ground is the foremost tactical decision. Not always possible, but when you have the choice, take it. Choosing the time is another tactical consideration, you'll stand a better chance at night in most cases.

As far as I'm aware, from the way WW2 sonar on destroyers worked, there would be several situations where it would be less effective, these being the times when you can crank up the motors and gain some distance.

You probably know that as a destroyer approaches a contact for a depth charge run, it invariably goes to full speed and you can hear this on your hydrophones. The speed degrades the quality of its contact, and as it approaches the point where it would pass over the sub, it would actually lose the contact because of the way its sonar system was configured. It would also be unable to reacquire the contact after passing overhead, since the sub would be in its baffles as well as being masked by the sound of any depth charge explosions for quite some time. This is of course why systems which threw depth charges forward of a destroyer were developed (such as Hedgehog). It's also why you see destroyers working in pairs and groups and flashing aldis lamps at one another like crazy, as they can triangulate your position with several bearings from sonar, which is why running slow is not always a good choice, since it makes the destroyer's triangulated position good for some time. Working in pairs and groups also overcomes the problem of a destroyer losing the contact as it gets close to some degree.

What this means is that when you hear a destroyer throttle up, there's a good chance that he's committed to a decision to drop DCs and so going to flank speed and throwing the rudder hard over, whilst not stealthy, is the prudent thing to do, since at this point he either has your location bang on, is being fed information from another destroyer, or is guessing at it. In any case, I regard it as time to haul ass.

Changing depth is another useful tactic (both up and down) however down is favourite, and not just because it makes sound detection more difficult, changing depth downards will also be quicker as you have gravity driving you forwards. And since water pressure increases as you go deeper, greater depth effectively makes near misses from depth charges less damaging too, because the force of the explosion has more pressure to overcome. The downside to this is that if a depth charge actually hits your hull when running very deep, it's likely to do catastophic damage as the pressure will tend to make it act like a shaped charge. This principle was used to great effect in WW2 on the Ruhr Dams with the Upkeep Mine dropped from Lancaster Bombers, more commonly known as the 'Dambuster's bouncing bomb'. The Upkeep Mine used Torpex explosive (as did many torpedoes and depth charges) the reason being that Torpex contained Aluminium, which slows down the reaction of the explosion and makes the pressure wave from the blast last longer, thus causing more damage. The mine would actually roll down the wall of the dam underwater, exploding at a set depth, and using the water pressure to accentuate the blast damage.

Back in the world of subs, increasing your depth also means that any depth charges have a longer transit time, thus opening up the margin for error on the part of the detroyers and giving you more time to react.

If you are feeling brave (or at least simulating feeling brave) you could try going shallow and hiding under a merchant. I use this technique quite a lot if I get in a lucky position, as it confers several advantages. In the first place the merchant would mask your noise, secondly, even if the escorts locate you, they can't pass over your position, and finally, it can get the convoy tripping up over itself, which sometimes offers you the possibility to pull away a little, sneak up to persicope depth and go for a quick stern tube shot. You can often hit a destroyer doing this kind of thing, and while it might not be very sporting, it can get results if you think attack is the best form of defence.

Anyway, just a few ideas, most of which you probabaly already use, but in any case, good hunting!

[7Enigma]

Chock,

Thank you for that great post. Particularly the description of WHY a tactic was used.