Getting Inside a Convoy

[RustySubmarine]

At the moment, I am on my seventh patrol, in charge of a Type VIIB. Based at St Nazaire, Started my career Oct 1940. To date (January 1942) I have managed to sink 15 merchants and 1 Black Swan Class. Several of the merchants and the corvette, were sunk from within escorted convoys.

My first convoy encounter on my second patrol, proved to be a near disaster, as I received quite a bit of hull damage after depth charging. However, by managing to shake off two attacking destroyers, I manage to eventually get back to base, with three dead crew and just 40% hull vulnerability showing when I reached St Nazaire.

So I decided to change my tactics for dealing with my next convoy encounter. I decided to try and approach at the head of a convoy by waiting for the convoy to get within range. I remained on the surface, until I decided to submerge to periscope depth and rig for silent running. When any destroyers were getting a bit close for comfort, I went deeper to 40 meters and lay in wait until the destroyers had passed over, and I was getting very close to the merchants which were within easy targeting range. Still on silent running, I came to periscope depth, chose three targets and launched my torpedoes.

All three were hits, causing damage to a Medium Freighter, and eventually sinking a Large Tanker and an Ore Carrier.
After launching my first 3 torpedoes, I went back down to 40 meters and listened to the carnage caused by my action. I remained below the convoy for quite a few hours, until it was out of range. Then after several hours, came back to periscope depth, to access the situation. Most of the convoy had gone off into the distance, and I could see several of them burning in the distance. There was just one Black Swan Class sweeper, still within range and approaching, were a couple of straddlers approaching me about 5000 yards away, that had got left behind of the main convoy. Call it luck if you like, I managed to sink the Black Swan with my aft torpedo, then wait for the straddlers.

I waited until they were in range. A Tramp Steamer and a Small Merchant. I managed to sink the Tramp Steamer with tube 4. Having no available torpedoes left (due to silent running) I then headed away from the scene, still submerged at half ahead.

When I was at a safe distance, with the Tramp Steamer going through its death throws, I surfaced; and with joys of jubilation from the crew, we managed to live another day.
I managed to sink 6 ships on that last patrol with over 35,000 gross tonnes under my belt.

As the war progresses, it is doubtful that this method will prove successful, as this was, because more advanced detection from the enemy will be available and the range of aircraft patrols will increase.

But it is a method worth trying in the early part of the war. It takes quite a bit of time and careful planing, but it is possible, to avoid the escorting destroyers, by lying low and keeping quiet during the process and to get inside a convoy.

[Aktungbby]

English is a peculiar language " going through its death throws," is actually "death throes" from throe: "a hard painful struggle" :O: ie: when one is getting a 'wiggle-on from his agonistes d'morte, he may well terminate in rigor mortis. There are never 'joys of jubilation' aboard U-boats! There are however occasional Exultations of felicity:D such as 'hot-Damn' or 'Gotcha' or just 'Yea 4 us!' ! Otherwise: A magnificent attack report and advocacy of my favorite (and Silent Otto's)http://www.uboat.net/media/men/commanders/kretschmer_recent.jpg attack technique! Wait for it to come to you; rise within the convoy; and ...begin the carnage!!!:Kaleun_Salute:

[Zosimus]

I've been working on the best way to approach convoys for awhile. It's an interesting and difficult problem. I have divided it into four phases:

A) You're behind the convoy.
B) You're alongside the convoy.
C) You're ahead of the convoy, but not far enough ahead to dive and intercept.
D) You're underwater and maneuvering into position.

Excellent solutions at one visibility do not work well at other visibilities. It's a tricky problem and part of what makes the game enjoyable.

[maillemaker]

My optimal convoy attack approach is to get dead ahead of the convoy and then drive straight at them until I either see them or detect radar. Then I dive to periscope depth and go to silent running, less than 100 RPM. I aim head for the outer column, so as to avoid the lead escort. Sometimes I have to move at right angles to the convoy to get out of his way.

I try to stay more than 1500 meters from the lead escort, but have gotten away with much closer, especially in rough seas. You can never be sure what direction he's going to go in so it's always a gamble.

Once the lead escort passes by, I turn onto a track 90 degrees to the convoy's course, and adjust my speed until I get straddled by two columns.

Then I wait for them to cross my firing solution.

Early war, I suspend silent running as soon as I fire and get my crews reloading. Frequently you can get off two full salvos before the escorts find you. Then I dive full speed to 250 meters and go silent. Usually you can escape.

The later the war goes, the harder this becomes, until after 1943 it's usually not safe to attack convoys from within anymore. After that you have to be satisfied with Hail Mary shots from 5000+ meters outside the convoy.

Until you get homing torpedoes. :)

Then you can entice escorts to chase you and pick them off with ease.

Then return to the convoy and rip them to shreds.

Steve

[Zosimus]

Once I am in front of the convoy and proceeding in the direction of the convoy I calculate my net speed as (my true speed)-(the convoy speed) and use that number to figure out how far ahead I need to be to safely dive and intercept the convoy. If the convoy is going at 8 knots and I know my underwater speed is 2 knots, then I will need to be ahead by a ratio of 4:1

Once I am at the correct distance ahead I just dive, run silent, and turn to the right heading. At that point I am on a collision course with the lead ship. If, for some reason, the escort notices me, I can just dive and still pass directly under the lead ship. This generally causes the escort to have difficulties depth charging me effectively.

Once I pass under the lead ship I go scope up and take a look around. I can zoom in quite a bit and see the ships around me. Based on a rough look at the size, I choose my target and salvo it with a two-torpedo salvo at 3-4º and generally the ship will sink almost immediately.

As soon as I hit fire I also hit D for dive and go scope down. I simply dive while continuing blithely into the center of the convoy. I do not change course until I'm at least 70 meters under and perhaps as much as 100 meters or more. If I get pinged, I abandon silent running and go full speed ahead. Currently I find that about 179 meters eliminates any problems. I am willing to go deeper, I just have never found the need.

Assuming I'm not detected (the normal) once I'm 100 meters under I turn to the heading the convoy is taking and follow it underwater until I can safely surface and work my way back around again.

The method I use depends on the visibility and wind speed.

[RustySubmarine]

Thank you all for posting your comments on Convoy Attacking. Some very interesting tactics have been described. But as already has been said, it all depends on the circumstances regarding, distance, speeds, time and weather.

I find that night attacks can be more advantageous than day time attacks, but this is not always the case.

However, each situation can not always have the same outcome and this is where careful planning needs to be taken into consideration.

Any more comments on this topic will be appreciated, it's great to hear how different sub commanders deal with the situation, when confronted with close contact convoys.

[Zosimus]

Here's how I work out how to get around a convoy to the front.

First I locate the convoy and determine the convoy's speed and direction. Once that's done, I want to get far enough away from the convoy to surface and move to the front.

I draw a line parallel to the convoy showing its course. In this case the convoy is moving at 81ºP or Heading: 279º

Next I pick a point where the line crosses a gridline and consider that ground zero. From there I measure along the line proportional to the speed of the convoy. In this case the convoy is moving at 8 knots, therefore I measure 2.4, which is 3x the speed of the convoy.

After that I draw a circle at 3 times my surface speed. In this weather I can easily make 11 knots on the surface, so I draw 3.3 radius circle.

http://i42.photobucket.com/albums/e350/Elias_Latour/SH3Img11-12-2014_123725_905_zpse03329ea.png (http://s42.photobucket.com/user/Elias_Latour/media/SH3Img11-12-2014_123725_905_zpse03329ea.png.html)

Next I measure a 90º angle from the point on the line that represents the speed of the convoy and draw a line until it crosses the circle that represents my surface speed. A line passing through ground zero and the point where the circle and the perpendicular line cross represents a good course to take. It is a course that will keep me from falling farther behind the convoy while getting me farther from the convoy as quickly as possible. In this case the number is 38ºP or Heading: 322º although I actually set my course for 320º so I would catch up slightly.

http://i42.photobucket.com/albums/e350/Elias_Latour/SH3Img11-12-2014_123747_882_zpsacd9f24b.png (http://s42.photobucket.com/user/Elias_Latour/media/SH3Img11-12-2014_123747_882_zpsacd9f24b.png.html)

Once I'm a bit away from the convoy I can surface and try to move around the convoy. I simply parallel the convoy until I spot a ship, like this corvette.

http://i42.photobucket.com/albums/e350/Elias_Latour/SH3Img11-12-2014_124240_563_zpsa23e794f.png (http://s42.photobucket.com/user/Elias_Latour/media/SH3Img11-12-2014_124240_563_zpsa23e794f.png.html)

To make my way around the corvette, I draw a line in the direction of the convoy through the ship I've spotted and I draw a circle from a point slightly ahead of the ship. I set my course tangent to the circle formed. Ideally this should keep me far enough away from the ship to keep from being spotted. The right radius for the circle depends on factors such as weather, your speed, the ship's speed. In this case 9.0 was too aggressive. I was spotted.

I guess next time I'll try 9.5.

[Gallimundo]

Invaluable info, have been a bit perplexed as a newb trying the convoy missions.

[Aktungbby]

Gallimundo! :Kaleun_Salute:

[Jimbuna]

Welcome to SubSim Gallimundo :sunny:

[Foggy]

I just finished reading Grey Wolf, Grey Sea, the account of submarine U-124 on my Kindle. Johann Mohr liked to get inside the convoy and take the ships down from within at night (he said that even with star shells and a flaming ship lighting up the night it was hard for other ships to locate him because they didn't expect him to be within the group).

[sharkbit]

Unfortunately from what I've read in these forums and from my own in game experiences, it is next to impossible to recreate in game that style of attack. It would be cool if you could though. It's nerve wracking enough just trying to penetrate the escort screen.

[sublynx]

I just finished reading Grey Wolf, Grey Sea, the account of submarine U-124 on my Kindle. Johann Mohr liked to get inside the convoy and take the ships down from within at night (he said that even with star shells and a flaming ship lighting up the night it was hard for other ships to locate him because they didn't expect him to be within the group).

There is no greater pleasure in SH3 than a surface attack at close range followed by an undetected escape on the surface. Unfortunately the restrictions of the game mechanics does not really allow the kind of attack you described, except in zero visibility conditions pre-radar. At least to my knowledge. Different megamods of SH3 have different visibility settings.

For those of you players who'd like to try the techniques Zosimus described, but without the contacts showing on the map, this manual might be of help:

https://archive.org/details/maneuveringboard00unit


Oh, and I found this site with video lectures on vectors and maneuvering board work. In the first clip showing how to use a mobo for getting the true course of the target and its relative motion takes about 30 seconds, the rest is repetition and basics:

http://vimeo.com/navigationtraining/videos

[maillemaker]

Unfortunately from what I've read in these forums and from my own in game experiences, it is next to impossible to recreate in game that style of attack. It would be cool if you could though. It's nerve wracking enough just trying to penetrate the escort screen.

You can do it, but you had best do it pre-1941 when the merchants are unarmed. Because they will light you up otherwise.

I find that once you've gone to the trouble to penetrate the convoy it is just as easy to stay submerged. The only exception to this is in extremely poor visibility when you have to move to find targets in the soup. But then the problem is by the time you see them often you are inside torpedo arming range.

Steve

[Kaptlt.Endrass]

While not recommended, I will, in the case the escorts are in a ring set apart from the merchants, go in from the front. For example...

(Last month, Western Approaches [AM77])
(July 1942)

Recieved report of a convoy at 0730-ish, went to flank speed and plotted a head-on meeting. Spotted the lead escorts around 0800, dove to periscope depth and reduced speed to ahead 1/3, rigging for silent running. From my position, I observed the convoy as the lead escorts, a J&K-class and a Hunt II, approached. Recorded speed before escorts closed to within 600 meters.

From there, I lowered the perisope and killed the engines, listening closely as the two destroyers came perilously close. After three minutes and a quick look-see, I restarted the engines to one knot, angling AWAY from the convoy center.

When the lead merchants were 900 meters out, I made a turn into the convoy, easily slipping into its midst. Choosing a large tanker and troop transport as my targets, I lined up the tubes and fired. One detonated early, but the short range meant that no manuvers could be carried out. The remaining three hit as I put my stern shot into a coastal freighter and dove to 60 meters, still at one knot. From there, I turned to the convoy's end and snuck out undetected.

================================================== ======
So, that's how I do it sometimes. Other times, I'll hit them from outside the screen, or if it 1939-early 40, I'll maybe take out lone escorts or escort pairs before surfacing and gunning the enemy merchants down.

[GJO]

You can do it, but you had best do it pre-1941 when the merchants are unarmed. Because they will light you up otherwise.

I find that once you've gone to the trouble to penetrate the convoy it is just as easy to stay submerged. The only exception to this is in extremely poor visibility when you have to move to find targets in the soup. But then the problem is by the time you see them often you are inside torpedo arming range.

Steve

In the early war years the chances of being damaged or even detected, when on the surface, are relatively slim in 'poor' visibility but beware of those battleships and cruisers that can sometimes be found right at the centre of a convoy.

My preferred method for dealing with poor visibility (only with slow convoys) is to manoeuvre onto a parallel course right inside the convoy - because this is where the juiciest targets are usually found. Either on the surface or at periscope depth, having picked and matched my speed to the target I stay on a parallel course at a range of about 450 metres and set up a shot at a 90 degree giro angle. With faster targets coming on a parallel course from astern of me I can sometimes get them with a stern shot but this requires much more precision. I have successfully sunk battleships and cruisers with this method - with big targets like battleships I usually fire a salvo of four torpedoes at a three degree spread angle - one of the four will often fail but three hits (especially if one hits near the propellers) can be enough to stop a battleship and if it hasn't sunk by the time that the convoy has moved on (and the escorts have lost interest), it will just sit there as an easy target.

Later in the war, when reliable and superior electric torpedoes are available, the merchants are all too often armed and the escorts have such sensitive listening skills that getting in close becomes just too hazardous but at least they won't see your torpedo tracks.