Any tips on approaching convoys undetected?

[Zero Niner]

I'm on patrol SW of Taiwan, I spot a convoy with 4 merchants and 2 escorts (a DE and a subchaser). I determine its course and speed and get ahead of it and submerge to ambush it.
Speed 1kt, silent running, RPMs <100, I'm perpendicular to the convoy's course at a range of 3000 yds or so to convoy's baseline when the DE starts pinging.
How does he do it when I'm quiet and he's on the other side of the convoy?
How can I ambush the convoy and approach undetected when I can't, even on silent running? Even at all stop he still hears something and starts looking.

[propbeanie]

Several things to try. First of all, do not approach when the sea state is like a sheet of glass, if at all possible. Second, attack nose on or tail on, and turn as the escorts start by. In conjunction with that, try to stay out of their "cone". Third, find the thermal layer prior to the convoy's arrival, and approach from below that if possible, and come up as the escorts pass overhead. Do your shooting, and then get back below the thermal as you slink away to reload. It can sometimes work to do Ahead Flank while doing that, if you already have an escort headed your way. You might have to do a combination of 1, 2 & 3. Fourth, if it is night time, and dark enough (no moon, clouds, etc), and the mod allows it, try a surface approach / attack. They can't hear you if you're not below the surface. The same rules of your sub's profile still apply though...

[jimmbbo]

I have had success when I

• Run ahead of the convoy outside the DD detection range, ending at a point about 10-15 miles ahead depending on convoy speed, 90 degrees from the course line, about 1000-3000 yds from the target's course.
  • The distance from course line depends on how accurate the computed course line is - closer with higher confidence
• Monitor the convoy course and refine the target course track with sonar or radar plots
• As the DD gets to within 5-6 miles, rig for silent running, dive below the thermal layer
• Set torpedo speed and depth, select torpedo to fire
• When the lead DD is about to cross the bow, begin ascent to just above 100 ft, call crew to battle stations
• When above 100 ft, open outer doors
• Rise to periscope depth, select target sequence for simultaneous impacts
• Time and conditions permitting/warranted, close distance to 1000 yd
• Fire away!

[LUKNER]

I'll add from myself. If the enemy uses active sonar and circles around you, then the great depth and silent smallest move will not save you. Try to leave at great depth with the maximum stroke at the moment when the enemy passes over you. Preferably in the opposite direction from the destroyer. Remember that you are in 3D space, change depth more often.


От себя добавлю. Если противник использует активный гидролокатор и кружит вокруг вас, то большая глубина и бесшумный самый малый ход вас не спасет. Пытайтесь уйти на большой глубине с максимальным ходом в момент когда противник проходит над вами. Желательно в противоположную сторону от эсминца. Помните что вы находитесь в трехмерном пространстве, чаще меняйте глубину.

[Bubblehead1980]

Originally Posted by Zero Niner

I'm on patrol SW of Taiwan, I spot a convoy with 4 merchants and 2 escorts (a DE and a subchaser). I determine its course and speed and get ahead of it and submerge to ambush it.
Speed 1kt, silent running, RPMs <100, I'm perpendicular to the convoy's course at a range of 3000 yds or so to convoy's baseline when the DE starts pinging.
How does he do it when I'm quiet and he's on the other side of the convoy?
How can I ambush the convoy and approach undetected when I can't, even on silent running? Even at all stop he still hears something and starts looking.

Are you running FOTRS? I forget.


Keep in mind that the escorts in SH4 are ALWAYS pinging when underway, even if you do not hear the pinging. You will only hear it once they focus the beam in your general direction, your profile to the beam matters as well, when they are not alerted. Example lead escort is coming and you're at closing in, but showing his sonar beam (which you cant hear yet) your broadsides, will get a hit, likely start hearing pinging or at minimum, will slow down to listen, and is now alerted as is rest of convoy. I would approach, keep profile low to the closest escort, perhaps dive just below thermal layer if possible, once the escort clears, pop up to periscope depth.

One thing is you are running too slow at 1 kt during approach. You are practically immobile at such a slow speed and does not make a difference in detection. Rig for silent running and run at 1/3, this will give have you at just over 2 kts, less than 100 RPM. Would only run at 1 knot when need to slow slightly when timing approach, or really trying to conserve battery power in extreme circumstances.

Kind of ridiculous because while on occasion did constantly ping, every escort was not always pinging. This makes it incredibly difficult at times to penetrate a escort screen submerged unless very deep, where as subs could usually sneak in at periscope depth or 100 feet. There is a hack that fixes this (Nicolas SH 4 Sonar fix) but it seems to do whacky things to the sensors once enemy is alerted when run with LAA, which is required with mods now, as the hack was designed long ago.

Then they have hydrophones and depending on their speed, sea conditions, your speed, type of hydrophone, skill level of escort, sensitivity of the sensor etc. Most of these such as skill level, type, you will have no idea about at the time.


If he is actually hearing you approach on silent running at 1 kt from other side of convoy, then the hydrophones are a bit too strong lol, need some adjusting.

[Zero Niner]

Are you running FOTRS? I forget.

Yes, 1.7

[LUKNER]

Со скоростью в один узел к конвою не подкрадываются. Эта скорость как правило позволяет удержать лодку на глубине, иначе она провалится или начнет всплывать.
Со скоростью в один узел к конвою не подкрадываются. Эта скорость как правило позволяет удержать лодку на глубине, иначе она провалится или начнет всплывать.

At a speed of one knot, they do not sneak up on the convoy. This speed usually allows you to keep the boat at a depth, otherwise it will sink or start to float.

[Armistead]

It's really just odds and stacking them in your favor. I actually prefer to stay at periscope depth where the sonar cone is narrow and split the middle of say two escorts and keep my nose pointed by helming to the nearest escort until it passes. If a lot of escorts I prefer to attack at night and will fire a torp from long range out of sight like 12,000 yards using radar. The goal isn't really to hit anything but at least try, but the torp will pull a few escorts away and start searching. Just watch which escorts leave their post and position yourself on an unguarded flank submerged while they're hunting elsewhere.

[LUKNER]

Originally Posted by Armistead

It's really just odds and stacking them in your favor. I actually prefer to stay at periscope depth where the sonar cone is narrow and split the middle of say two escorts and keep my nose pointed by helming to the nearest escort until it passes. If a lot of escorts I prefer to attack at night and will fire a torp from long range out of sight like 12,000 yards using radar. The goal isn't really to hit anything but at least try, but the torp will pull a few escorts away and start searching. Just watch which escorts leave their post and position yourself on an unguarded flank submerged while they're hunting elsewhere.

This tactic was developed by the conditions of a computer game. In reality, it is difficult to agree on the use of such a decision-making model by the captain, who must motivate his actions to the command and crew. Unless, of course, the target is extremely important and there are simply no other ways to hit it.

[simon1138]

here are two videos i watched about the same thing you are trying to do