Convoy nonsence

[slupanter]

dear those it may or should concern. is it me or is it really hard to attack convoys? i can get in to harbors easy enough but can never get close to convoys (underwater). whats the answer to a good convoy attack

[Leg]

try to attack at night and surfaced... on surface you have an higher speed than the convoy... so get in position ahead of the convoy and get close to it.. then if you are early in the war stay on surface and attack, if there are radars around... well go to pd and attack...

[Bronzewing]

Depends when you're doing it. My current patrol in early 1941 has me lurking in high seas in the middle of the front rank of a small convoy of abut 10 merchants, mostly small vessels, and only two visible escorts (may be another on the other side) one of them a flower corvette and the second a frikking ASW TRAWLER! With an escort like this, and being night time and bad weather, getting in was exceedingly easy.
(I don't usually save during a convoy attack, but as such things usually happen I ran into it right before I had to leave for an appointment.)

[RoaldLarsen]

Originally Posted by slupanter

dear those it may or should concern. is it me or is it really hard to attack convoys? i can get in to harbors easy enough but can never get close to convoys (underwater). whats the answer to a good convoy attack

The answer is: don't get detected.

Okay, longer answer:

To make an effective attack against a convoy you need to get inside the escort screen undetected and fire from short range at 0 gyro angle.

To do this you will need to know exactly where the convoy is going to be, so you can be there waiting for it. That way you won't be manouvering at speed close to the escorts and thereby increasing your chance of being detected. You want to arrive before the escorts are in radar, visual or hydrophone range. Depending on the convoy's speed, this can mean arriving up to two hours before your intended attack. Ideally you want to get to the precise location from which you will fire torpedos. Practically this is very difficult, but you want to be close enough to this spot that you can make all necessary position adjustments submerged at periscope depth at a speed of 1 knot.

To get into the correct location in advance requires carefully measuring the convoy's course and speed. Ideally you also want to count the rows and columns, get the spacing between ships, and identify the location of the juciest targets, but this gets harder to do as the war progresses and allied detection technology improves. Anyway, gather as much of this information as you can, and then scoot ahead to your chosen intercept location. Timing your attack for night time reduces the chance of you being seen, but also reduces your ability to see your targets.

A typical convoy escort has a ship in front of the convoy, one or more ships on each side and one in the rear. The lead ship is on the convoy's mean course, and the side escorts are in a lane parallel to the course. All these escorts are usually moving from side to side or circling, to expand the width of their detection zone.

You want to position your sub about halfway between the mean course and the side escort's track, perpendicular to the convoy's course, motionless, at periscope depth, rigged for silent running. This position should usually be enough to avoid being detected by the escorts as they deviate from their notional straight line course. The risk is, if you get too close to the lead escort's track, it will be pinging you while you are presenting your side to it. If you are correctly postioned, then they will only be pinging you when they have turned toward you and you are then presenting a narrow profile to them. If you are too close to the side escort's track you will be too far from the merchant ships and the side escort may detect any manouvering you have to do to get closer, or, if you don't manouver, the side escort will be able to ping your side aspect.

It is very hard to get to this ideal position. Once you have taken up what you think is the correct postion, as the convoy approaches you use your hydrophones to follow the positions of the lead and side escorts. If you know the course and speed of the convoy, and the average distance from the lead escort to the centre of the convoy, then you should be able to calculate the precise range of the convoy centre to your perpendicar course at any time (and the precise time of intercept) but also the approximate range to the lead escort at any time. Use the hydrophone bearing and the estimated range to the lead escort to adjust your position forward or back. Only move forward or backward at 90 degrees to the convoy's course, at no more than 100RPM. Do not use your periscope to fine tune your position relative to the escorts.

Once the lead escort is past you, wait until you are closer to a merchant than to an escort, then move ahead at 1 knot. Another advantage of your postion is that most of the convoy will pass in front of you but one or two columns may be behind you for your stern tube(s).

Use quick peeks of the scope to select a target at least two columns away for a fast 90 attack, and a second, closer target for whatever sort of attack will hit it if you shoot right after your fast 90. Take a quick look around to make sure you will not be run over by anyone, and perhaps to identify a second fast 90 target or a stern tube target. Adjust your speed to stay between columns. Don't keep your scope raised all the time. At the correct moment, make your first fast 90 attack, then immediately take a range measurement for your next target, set the range in the TDC and fire again. If you feel safe from detection then make another fast 90 or stern attack.

Once you have fired the last torpedo, lower your scope. Don't leave the scope up looking to see if you hit anything. Dive straight ahead, set depth to maximum. Use the hydrophones to check if any escort has located you, or at least has charged the approximate firing location. If it has, go to flank speed to get far away from where you attacked and to increase your dive rate. When you are near or just past the middle of the convoy, drop a Bold decoy, with 10 degrees of rudder turn in the direction the convoy is heading, and reduce speed to 100 RPM. Proceed to evade.

If no escort seems to be pursuing you when you first make your post-attack hydrophone check, set speed to 1 to 2 knots, wait until you are halfway between the convoy's centreline and the track of the far side escort, then use 10 degrees of rudder to turn to the opposite course from the convoy and exit between the side escort and the tail end Charlie.

An early war variation of all this is to make your attack at night on the surface with decks awash (this requires a mod). Keep your speed very slow to minimize the chance of detection.

The approach I have outlined works for me. Others may have different ideas that also work. As I recently posted in another thread, it has been 86 combat patrols and counting since I was sunk by a convoy escort. I haven't counted the number of convoy attacks I have made in that time, but I expect I'm averaging more than one convoy attack per patrol. Please note that I am not running GWX, so I can't be sure that GWX sensors won't negate this. However, if they do, I doubt it is possible to make submerged attacks from within the escort screen, and that wouldn't be realistic.

Originally Posted by slupanter

is it me or is it really hard to attack convoys?

The reason the Allies used convoys was that they were extremely hard to attack. U-boats had a great deal of success up until March 1941. As stated in other posts, most attacks were surfaced and at night. This nullified Asdic and gave the U-boats greater speed. In fact, the U-boats were faster than all escorts but the destroyers.

That said, the early convoy successes were due to the wolfpack tactic; mutiple U-boats attacking at once from several directions. This overwhelmed the escorts and allowed at least one or more surfaced U-boats to get within the escort screen to attack.

However, as good as SH3 is and as fantastic as GWX3 is, the game falls short on this one point. It does not portray muliple U-boat attacks very well, if at all. Thus, your single U-boat battles all the escorts by itself. And this makes the night surfaced attack very difficult. In my opinion, the escorts are able to spot the surfaced U-boat way to easily for realistic results in the early war years. This forces most of us to use a slow submerged attack instead, which is not realistic at night due to minimal vision of the real attack scope that was probably never used at night.

[Kubryk]

RoaldLarsen, could you tell me which mod enables deck awash option?

[Pepe le Moko]

GWX III does it, maybe there is a stand alone mod too but i don't know.

[RoaldLarsen]

Originally Posted by Kubryk

RoaldLarsen, could you tell me which mod enables deck awash option?

As stated above, GWX definitely includes this. I think the other supermods may also have it. Wreford-Brown has a small mod available in the downloads section of this site that does three things IIRC: allows decks awash, exchanges the snorkel depth command for a decks awash depth command, and changes one of the forward speeds to be what he thinks is the most fuel efficient.

None of these are to my taste, so I made a modification to allow decks awash by using SH3 Commander's static settings file. Read about it in post #10 of this thread.



The downsides to my version are:

1. to lower the sub to a decks awash depth you have to set the depth manually on the depth guage (7.9m or less for type VIIs and 8.1m or less for type IXs) rather than pressing a keyboard shortcut. For me, this was less of a problem than losing the snorkel depth command. YMMV. This limitation may also apply in the supermods, IDK. I only know that Wreford-Brown provided a shortcut key to get to the maximum depth for decks awash without having to use the depth guage, and did so by eliminating a shortcut key I use frequently.
2. My mod is not JSGME ready. You actually have to either type in an SH3 Commander file, or edit one line in each of several config files.

The upsides to my mod are:

1. It won't conflict with other JSGME-ready mods to the submarine configuration files.
2. It doesn't sacrifice a standard shortcut key.
3. It doesn't add any other potentially unwanted effects. It just enables running with decks awash.
4. Implementing it, either by editing the SH3 Commander file or by editing the several sub config files, will give you a simple introduction to tweaking the game to suit your own tastes.

[Synthfg]

In mid/late war when any surface approach is impossible
I find it best to position myself ahead of the convoys projected path, dive and approach head on in silent running mode,
slip past the front escorts, hit the largest ships I can find before the escorts home in on me
when it gets too hot, go deep silent running and exit out of one of the convoy rear quarters,
when the escorts give up surface and reload whilst racing around the convoy for a repeat
remember to co-ordinate your hydrophone checks with the torpedo loading

[Kubryk]

Roald and Pepe, thanks for answers. I don't mind fiddling with cfg files as long as I backuped 'em But for now I will stick with stock in order to finish my first campaing. It's somewhat easy and boring sometimes, but year is still 1940 and maybe it will become more fun. Then I'll go for GWX and Commander, and amuse myself with tons of mods out there, I'll start with some nice skins and gramophone tunes

Now if you'll excuse me, I've got some ships to sink

[slupanter]

Originally Posted by Kubryk

RoaldLarsen, could you tell me which mod enables deck awash option?

good point. the boat sail way to high.

[slupanter]

Originally Posted by Kubryk

Roald and Pepe, thanks for answers. I don't mind fiddling with cfg files as long as I backuped 'em But for now I will stick with stock in order to finish my first campaing. It's somewhat easy and boring sometimes, but year is still 1940 and maybe it will become more fun. Then I'll go for GWX and Commander, and amuse myself with tons of mods out there, I'll start with some nice skins and gramophone tunes

Now if you'll excuse me, I've got some ships to sink

Im in 1944 about 9 of june use a type xxi.

thank you all for your advise.

[Brag]

For decks awash, order depth 6 or 7 meters.

For convoy attack you may want to read the related article on my kielman website.

[Captain Nemo]

Originally Posted by von Zelda

However, as good as SH3 is and as fantastic as GWX3 is, the game falls short on this one point. It does not portray muliple U-boat attacks very well, if at all. Thus, your single U-boat battles all the escorts by itself. And this makes the night surfaced attack very difficult. In my opinion, the escorts are able to spot the surfaced U-boat way to easily for realistic results in the early war years. This forces most of us to use a slow submerged attack instead, which is not realistic at night due to minimal vision of the real attack scope that was probably never used at night.

Whilst I agree with your point on the lack of wolfpack tactics employed by the game, I find night surface attacks during the early war years to be achievable with rewarding results. Since GWX Gold and using the 16km atmosphere, which makes nights a lot darker, I find I can cruise up and down the convoy lanes at ahead full without being detected. Having said that, using the previous version of GWX and the 8km atmosphere, things get a little more trickier in that in my experience you need to keep your speed down to slow to avoid detection. Although I'm sure that decks awash gives you some advantages over being fully surfaced, its a tactic that I rarely employ.

Nemo