Drawing on your experience...

[Seaveins]

Although I am on my (8th) patrol I would like to buy a round of biers in exchange for your advice on attacking convoys. It is the summer of '40 in a VIIB with an experienced crew. I, however, am not the best Kaleun and don't want to lose these guys due to my inexperience. I am not having success tracking or attacking convoys. To track them I consistently end up too close and end up getting chased (DC'd) away and lose the convoy. I have tried to position myself ahead of the convoy and hit the ships as they pass around me but seem to always pick the wrong place to periscope up. Ships are too close, too far away (for my skills and/or luck), or heading right for me so I need to crash dive. In any event, I am frustrated with my lack of success and this is the supposed to be the "happy time". If this continues, I am heading for a stagnant career, certain death, or worst case...a desk job retrieving coffee at BdU! S.O.S.

[UnderseaLcpl]

Hello Seaveins!

I hope this advice can help you but these are just my personal methods. Some of the cleverer Kaleuns probably have better methods.

1) Location, location, location; I always hunt convoys in places I'm bound to run into them, principally grids am52 and bf 15. There isn't much room for them to slip past me in bottlenecks like that. Just west of the Gibraltar Strait is another good locale but I seem to run into single ships much more often than convoys there.

2) Patrol your killzone of choice at periscope depth by nightfall, going deeper in the daylight to preclude aircraft from happening across you and bombing you to bits. It doesn't happen often but it can happen. Keep the scope down and ABSOLUTELY NO SCHNORKEL! I am convinced that the schnorkel is not made of metal, but some strange magnetic substance that attracts every plane, destroyer, and patrol boat for miles around.
You most likely won't have too much trouble with enemies locating you while patrolling until later in the war but the above are good S.O.P.'s to form habits around.

3) If you are at periscope depth, in addition to having a much greater detection radius, you can still get contact reports. This helps immensely.
Once a contact develops pick the first "merchant" bearing line and track it at 8x tc
until you can develop a general heading for it. Just use your pencil and plot the end of the line whenever it moves. Make sure you are zoomed in on the map to a fairly close level as the bearing lines at lower zoom levels tend to be off a bit. Take as many plots as you need to be confident that you know the convoy's general heading.

4) Pick an intercept point. I'm afraid this requires a little practice and some brainwork. First thing to account for is convoy speed. If you get a contact report this has already been solved for you but your hydros will only give you slow, medium or fast, as you know. Assume slow is 6kts, medium is 9 and fast is at least 12. I don't think I've ever seen a fast convoy.
Next, plot a rough intercept course at full or flank speed on the surface and query the N.O. for "time till course end". Next, use the convoy's speed and the compass tool to see how far the convoy will move in the time for you to reach your destination. I use a trial and error process until I get a "course end" that is an hour or two ahead of the convoy. Don't get much farther ahead than that because there is a good chance they will change course and then you're back to square one.

5) Haul a$$ to the intercept and dive to periscope depth. Put the e-motors on slow ahead. Try to gauge from the "fan" of bearing lines if the convoy is still making way towards you. Obviously, the fan will get wider if they are approaching you head on.
Eventually, you will develop an eye for the contact lines and can more or less assess the layout of the convoy just by looking at the bearing fan.
Pick a side to attack from and try to line yourself up with the outermost edge of that side of the convoy.
Using the compass, check the distance between yourself and the lead edge of the convoy periodically. When they are about 4000m away begin doing brief periscope checks. Use the nav map and the ship plots that will appear on it to draw lines along each column's tracks. This way, when you have the scope down or are deep during the attack you will still have a good idea of where the ships are.

6) Pick two adjacent columns to attack and nominate target ships. If there are no desireable targets on your side of the convoy it is usually best to let it pass and then run around in front of it again rather than trying to zip over to the other side before the lead escort gets too close. He will almost always detect you unless the sea is very rough.
Also, calculate the speed of the convoy precisely if you don't have it already. If you don't know how to do this I'm sure someone will be happy to explain it to you in this thread or there are several other threads on that topic.
When you have decided which ships to attack, position yourself in between the target tracks, put the scope down and wait. I personally don't go "all stop" I just go ahead slow and back slow to station-keep but feel free to stop the motors if you wish. If you're not already in silent running, toggle it now.

7) The key at this point is good, quick shooting. Since all my torpedo deflection calculations are done in my head I never have a problem with this, but if you must use that newfangled TDC contraption, set it up now. I personally don't really know how it works but I assume the solution for a 90AOB shot at a target with a known speed from about 500 yards is probably pretty easy.
You can peek with the scope for short intervals but keep it as low as possible. If even one ship sees that thing you'll blow the whole attack and their zig-zagging will make things harder for you. Plus, the escorts will be headed your way, naturally.

8) As you develop your skills you shouldn't have to do as much pen-and paper crap to intercept and successfully attack, but it still helps on occassion.

9) Once the attack is completed, dive underneath one of the convoy lanes (this is one reason why we drew those lines along their tracks )or pick an escape vector, go deep and stay quiet. Keep moving but only at ahead slow, that's the only speed that can fox their hydrophones. The escorts will have difficulty accquiring you or holding on to your contact as they try to avoid colliding with their merchantmen and each other. If you have BOLD, drop one every once in a while, but save at least five just in case a persistent escort manages to hang onto you. I won't discuss evasion tactics here but there is a lot of good information about this on the forums and some user websites. Try Brag's page, it's good.

10) Final word of caution. If you are compromised or in danger of being compromised it is best to just abandon the attack and try to run around again. If the convoy changes course, don't try to get into an attack position submerged or increase speed, you'll just get caught and blasted.

11) If you like, there are also some good threads on attacking escorts. Obviously, if they are underwater, you can do whatever you want with the convoy.

Whew! Sorry so long but I hope it helps a bit.
Happy Hunting!

[pensfan]

UnderseaLcpl,

Great response! I'm a newbie on my second patrol and find your info most useful. I hate to admit this but I did not even fire a torpedo on my first patrol.

Al

[predavolk]

That's a good summary Undersea. I would add a couple of things.

1- Don't worry about their arrival time to the intercept point. Get there yourself ASAP. Then turn towards the convoy and head towards it 1/3 ahead on the surface. If you have radar detection (later in the war), dive once you pick up a radar signal. If it's earlier in the war, go in with decks awash (depth 7M) and dive when you get a visual contact (preferably with your own eyes before your watch spots the ship). This helps solve the problem of convoys changing course as you are reducing the amount of time they have to make one.

2- If you have to chase a convoy from the side or stern, make sure you swing at least 15K away from its outer escorts. This is generally the outer range of their radar or vision. Radar can be a little farther, like 17-18K. So 20K is probably a safe bet. Make a course that looks like this "[" where you angle out, run parallel, then angle back in. All done Ahead Full or Flank on the surface.

3- Adjust all your torpedoes on the way in. This reduces last minute snags.

4- Do not let the front escort get within 1 km of you if possible. 500M is certain detection. You then have to run and gun, or dive and hide. Try to use the sonar contacts to determine what side of the convoy the front escort is leaning towards, then try to attack the opposite side. The front escort is really your biggest challenge in penetrating the convoy unnoticed.

5- BdU gives you the speed of the convoy in the convoy report, so if it's a reported convoy, you've got that work done for you.

Good luck hunting!

[UnderseaLcpl]

Thanks for filling in the gaps Predavolk. I guess I left some thing out while trying to keep that post from being unbearably long. I totally forgot about the radar detector!

[Laufen zum Ziel]

I Learn something every day from this forum.
Great response from forum members makes this
forum what it is.

[Seaveins]

As always, thank you for your responses. I will try a new approach tonight with the tools you have shared. Do any of you know when Allied radar became commonplace on escorts?

[UnderseaLcpl]

Originally Posted by Seaveins

As always, thank you for your responses. I will try a new approach tonight with the tools you have shared. Do any of you know when Allied radar became commonplace on escorts?

My approach is to assume they have it as early as Sep. 1940. Maybe they does and maybe they doesn't but caution never hurts.
This belief is derived from a destroyer I encountered in a storm in Sep. 1940. Maybe he just had REALLY good lookouts or a similarly talented hydrophone operator but as I was sneaking past him he suddenly veered in my direction. Luckily the bad weather ruined his ASDIC reception and I escaped unscathed by going deep and silent.

IRL march of 41 was the first detection by radar of a U-boat that resulted in a sinking. The boat happened to be U-99 under Otto Kretschmer. However, I am unsure as to how radar developments are modelled in-game and the allies indubitably had radar ship-mounted radar before this.

[Seaveins]

Now that I am armed with better tactics, I can't shake this storm off U-51. The rain and wind has been relentless for 6 days in the AM52 area (Sept/40) and I keep tracking this great convoy that has almost reached port. The only light on this patrol has been accidently running into (not literally) the H.M.T. Aquitania. All 45,557 tons in exchange for one torpedo! Other than that the crew has smelled and felt better. We have been burning fuel for weeks and still have 12 torps. Any credit for not letting them loose willy nilly?

If it's any consolation my U-1030 is in AM52 in September 44 and the storm is still going strong...

Good Hunting

[UnderseaLcpl]

Originally Posted by Seaveins

Now that I am armed with better tactics, I can't shake this storm off U-51. The rain and wind has been relentless for 6 days in the AM52 area (Sept/40) and I keep tracking this great convoy that has almost reached port. The only light on this patrol has been accidently running into (not literally) the H.M.T. Aquitania. All 45,557 tons in exchange for one torpedo! Other than that the crew has smelled and felt better. We have been burning fuel for weeks and still have 12 torps. Any credit for not letting them loose willy nilly?

You're not the only one.

[Sailor Steve]

Originally Posted by pensfan

UnderseaLcpl,

Great response! I'm a newbie on my second patrol and find your info most useful. I hate to admit this but I did not even fire a torpedo on my first patrol.

Al

WELCOME ABOARD!

[Kptlt. Neuerburg]

My experience has taught me that its not tracking the convoy thats the hard part. As most people will tell you its getting away from the escorts. I have devloped a tactic that is both effective and highly dangerous which is to approch a convoy and destract the escorts on one side of the convoy by running at a speed that they can hear. When they turn and start towards you go slient and deep FAST!! When the escorts are destracted move in and make your kill. Then go back down and make your escape. This does work well on the early convoys on '39 and '40. Another thing to try is to go and use a ship as a hat like in Down Periscope, it does seem rather silly but it does in fact work. I did use this very successfuly in sinking a RN Battleship that was in the middle of a convoy and eluded the escorts long enough to fire three torps into the ship at it keel depth. Try them some time and see how it works. And it helps to have an outside view to see whats in the convoy. Remember the bigger the better!!!

[UnderseaLcpl]

Originally Posted by Kptlt. Hellmut Neuerburg

My experience has taught me that its not tracking the convoy thats the hard part. As most people will tell you its getting away from the escorts. I have devloped a tactic that is both effective and highly dangerous which is to approch a convoy and destract the escorts on one side of the convoy by running at a speed that they can hear. When they turn and start towards you go slient and deep FAST!! When the escorts are destracted move in and make your kill. Then go back down and make your escape. This does work well on the early convoys on '39 and '40. Another thing to try is to go and use a ship as a hat like in Down Periscope, it does seem rather silly but it does in fact work. I did use this very successfuly in sinking a RN Battleship that was in the middle of a convoy and eluded the escorts long enough to fire three torps into the ship at it keel depth. Try them some time and see how it works. And it helps to have an outside view to see whats in the convoy. Remember the bigger the better!!!

Please elaborate on the "ship hat" technique. Every time I try it they can still ping me and they won't go away! I don't use the external camera for it but I do cheat and use the periscope to keep me under the ship. Ultimately I just end up wasting torpedoes to sink my assailants. What am I doing wrong?

[Kptlt. Neuerburg]

Ok I will say that the ship hat trick still works even if the DDs are still pinging you. Just concentrate on what ever ship it is your trying to sink. Sink it, dive and run like hell man!!