Online since 1997


U-boat Tactics

U-boat Tactics
by Fionn Kelly

Used in playing Aces of the Deep

I will deal with an attack on a convoy and how I deal with convoy battles plus give an example of an action I conducted last night.

An attack on a convoy usually follows the pattern:

Detection Maneuver into attack position Attack Escape


DETECTION: Well this happens whenever it happens and so I can't add anything to your detection methods except to stay on the surface if airplanes aren't a threat (pretty obvious, I know).

MANEUVER: I prefer to attack at night and from the midst of the convoy since these two conditions give me the greatest chance of escaping vengeful escorts (or so I feel, at least).

My preferred method of entry is to submerge and lie, almost silent directly in the path of the convoy. I believe that it is immensely important to place yourself at a point in space which negates, or at least minimizes, your need to maneuver while submerged in order to meet the convoy. The escorts in front of the convoy are very alert and I avoid speeds in excess of 1/3rd speed while approaching the convoy from in front.

This is all tactically sound but if I am restricted to maneuvering at 2 or 3 knots I must be positioned such that I won't have to chase the convoy for a good torpedo shot so I must develop a good estimate of the convoy's course so that I can position myself before them in a perfect attack position and thus remain silent and stealthy until the time comes for me to reveal my presence by torpedoing as many ships as possible.

I use basic trigonometry to estimate the perfect position for my submarine. As I run alongside the convoy I start my own plot of their course on paper. Historically (and in the game) convoys usually zigzagged at very precise times an pre-determined headings since such forward planning was necessary to keep the formation of a convoy containing merchant ships unused to station keeping. Usually the convoy had only 2 courses which lay on either side of a base course and in AOD I have yet to meet a convoy which has more than 2 courses in its zigzags.

At the beginning of the first zig after you are ready to plot take readings of the course, bearing, range and speed of the 4 ships at each corner of the convoy. I also begin developing a track on the central ship of the first row of the convoy since that is my favorite position to sneak into the convoy. It ensures easy access to the very center of the convoy when I choose to attack. Measure exactly how long the convoy maintains this course and then when they change course on the zag leg take the same readings for the same ships. Again measure the time until the convoy begins zigging again.

When you have this done you will be able to calculate exactly how far the convoy travels in each leg of the zig-zag and how long each leg takes with this information (and assuming the convoy keeps zig-zagging along the same courses and for the same amount of time).

On the piece of paper beside you accurately measure out your position relative to the convoy using a protractor and compass ( and since you have at least 4 bearings and distances to different ships in the convoy you will minimize any errors in working out your relative position) then map out the projected course of the convoy on the paper, then decide where on that course you wish to attack them.. pick your spot and plot a course directly for it. Note that using this method you can also choose a time of attack, say 0100 and figure out where on the future course the convoy will be and then just using your ruler and compass figure out the course and speed necessary to reach that point before the convoy.

While it is perfectly possible to place yourself near the convoys track this method allows you to incredibly precisely pick your attack point. If you see a particularly valuable target you can, using this method also plot a course to place you 4 or 500 yards from the future track of this one particular ship. Basically, using this method I have been able to place myself at a certain point, at a certain time and a certain distance from enemy ships, yesterday I decided I wished to launch torpedoes at 0300 from approximately 500 meters at a line of 3 troopships in the midst of a convoy. I calculated the necessary track for the troopships and then placed myself 500 meters from it on the correct heading and submerged deeply.

When 0300 came, I rose to periscope depth and let of my 3 torpedoes (commanding a Type IIC in 1940) at ranges of 600 to 460 meters and hit and sank all 3 troopships in the midst of the convoy. The strength of this method is that if used properly and with due care to minimize errors it allows you to forecast the course, pick a time and place to attack and even to pick the point such that you can be a set distance from a specific ship in the convoy. With such accuracy penetrating screens becomes easy and the only limitation on your kills is the number of torpedoes you carry.

When I reach my plotted position I submerge deeply to the maximum depth at which my engines running on 1/3rd power can keep up with water entering the boat (bilge pumps etc). If the escorts are particularly fearful I may go deeper and crank up to 2/3rds power but no higher. Obviously I continue circling so as to maintain station (no point picking the point carefully if you then cruise off it). An other option is to remain shallow and cut all engines and only dive deep if an escort is getting very close.

As you lie there submerged the enemy ships should be approaching. I usually aim for the center of the first row of ships (hence my taking a 5th reading of the center ship of the first row) since that gives me the greatest number of firing options--any direction I fire in I will probably hit something.

ATTACK: As the escorts are passed and the second row of ships comes into range I often come to periscope depth and at full stop (to minimize my wake) scan the second and first rows. I pick the biggest ships in these two rows and working from right to left or left to right (you choose) I begin loosing my torpedoes until all are expended. Then I instantly kick in my motors and dive as deeply as possible. I match speeds with the convoy and motor off to a portion of the convoy which is still packed with ships and use my depth and the noise of the merchant ships to mask any noises I make.

ESCAPE: Usually by carefully choosing a portion of the convoy far from where the sinkings took place and also not in the path of any in-charging escorts I can avoid notice. Once the escorts begin to withdraw and my tubes are reloaded I come to periscope depth, orient myself towards the oncoming merchants and again fire all remaining torpedoes. When all are expended, I dive deeply and motor directly out of the convoy towards the rear but away from the side on which the ships were sunk so that the search area does not include me. I find this often works for me and once I am a moderate distance away (since I attack usually at night) I can surface and run on the surface a safe distance away before returning home in safety.

If I am detected I slow to a crawl (2/3rd speed) to save battery power. The enemy has already detected me so there is no point running now. Save the running until they can't hear me anymore. Also I dive to the deepest I can go without taking in excess water. I would prefer to crawl at 1/3rd speed but the need to go very deep necessitates a higher speed so that my bilge pumps can work better. I like to stay at about 200 meters while under attack. I stay this deep because it takes some time for depth charges to fall through the water and this extreme depth gives me some extra time in which to change course, ring up extra speed and generally try to avoid the depth charges.

Once the depth charges have been avoided I will follow the escort from behind. Its sonar cannot work in an arc of approximately 60 degrees behind the ship. So even at flank speed I am invisible to the ship. Trailing along behind it I can leave the depth-charge point behind me and still remain undetected. After the ship has completed perhaps 1/3rd of its circle back to the depth charge point I go straight and level and lower speed slightly. The aim now is to move away from the escort's circles such that it won't detect me with its sonar upon its next circuit. Note that it is permissible (even advisable) to ring up flank speed while the escort has its stern towards you as it continues to circle. But as the escort's circle brings it heading towards you again reduce speed and stay deep. If you are successful in avoiding detection this time you should be safe and able to escape. If you are unsuccessful then you will have to re-attempt the whole procedure.


As an example of this I attacked a convoy containing some 40 merchants and 8 escorts in January 1940 with a Type IIC with only 4 torpedoes left (I'd already sunk 2 lone ships) And using exactly the tactics described above moved in and sank an 11,000 ton tanker, a 9,000 ton tanker and a 16,000 ton troop ship with my first 3 torpedoes. I then dived directly under an 18,000 ton troopship I had identified during my first attack and stayed there when the escorts came to investigate. When they left and I had reloaded I popped up to periscope depth, aimed and fired , dived deep and sped out of the convoy and managed to avoid detection completely.

With 4 torpedoes and at 100% realism I had just sunk 54,000 tons in 1 night which when added to the 17,000 tons from my first 2 sinkings gave me a respectable score.

NOTE that these tactics are even more devastating with a Type VII or IX and I fell it better to remain submerged during the whole attack since these tactics make very little demand on battery charge leaving plenty for evasion if necessary.

Hope this was a little helpful.

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1998 SUBSIM Review
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