Let's talk tactics

[ppk]

I'm introducing this with the story of my last patrol. I'm hoping someone can point out my mistakes.

On my last patrol I encountered a HUGE convoy. Bigger than anything I had seen before, it had more whale factory ships and other fat targets than I had torpedoes for. It is the end of 1942 and the Allies are pissing me off with their shipboard radars. The convoy was moving pretty fast and time for the intercept was limited because I was just at the edge of the continental shelf in grid AM and I only had a few short hours before they were out of my reach (I don't go in shallow British controlled waters ... Since it's a DiD career the safety of the boat supersedes my greed for more tonnage...).

So essentially I was between them and the coastline in the early morning, which is good, but then I got the ''detecting radar signals'' message. I submerged, and when listening to the hydrophones I realized that they were changing course. I went back topside, and turned away from them at flank speed. Still out of visual range, I made the bet that my minimized cross section wouldn't give them a solid return. I began flanking them but was relentlessly attacked throughout the day by patrolling hurricanes and such. To make matters worse I had to recharge batteries at flank speed because I still had used up some juice to hunt a task force during the night. So about at that point I thought about backing off and letting them be but decided to press on. From the plot I had I determined the latest position at which I could engage the convoy and still duck in deep water to evade and headed there.

''Detecting radar signals''...
I decided to test the efficacy of their radars a little. Still making flank speed, batteries now full and I've spent the day flanking them. I'm not ahead yet, and it looks like I'm gonna have to shoot at extreme range and hope for the best. So I turned right into the convoy (again, minimized cross section) until the first ship was spotted. After ducking to periscope depth I took a look and concluded that their radars had not picked me up. Everyone was sailing straight, no escorts coming towards here. But I also noted that they were REALLY far.

The minimum speed I could make to my only possible firing position was 6 knots... And I wasn't too sure if that was safe but did it anyways. Eventually someone must have heard me because before I knew it I had three DD's swarming to my position. So alright, no big deal, I turned away and one of them wasn't zig-zagging... I sent him some stern tube goodness and he broke in half. I'm not going to describe the rest of the engagement because it turned in a messy knife fight but 15 minutes later the two other DDs were at the bottom and I had lost my starboard prop to an ash can. There were three TI's left in my bow tubes, which I shot at long range. One hit a small freighter and the other two missed.

What's the fastest speed that we can travel at without being detected at different ranges? I know at really close range you have to be silent but how close can you come before you need to slow down? From what just happened I get the feeling that they heard me when I was about 5 km from the corner DD. How do you guys cope with radar to still get in a good position? It was the main hurdle preventing me from getting close enough for good shots. It forced me to retreat further from the convoy when flanking and consumed the few precious minutes I had to complete the intercept. Even though I did sink four ships it was a failed attack. The biggies sailed away unharmed.

What would you have done in the same situation?

[meduza]

I would do pretty much like you did, except I would risk getting further ahead of the convoy, into the shallow waters (even though I also play DiD). Because of the shallow waters, I would fire from greater distance than usual, about 4km, to have more time for escape before the impacts.

As far as the detection ranges are concerned, you can be heard from some 5-6km early in the war, and about 9km late. If you click on the ship's mark on the map, you'll see the circles representing maximum detection range.
If you're dead stop, silent runing, you can still be heard from some 300-500m early, and 1000-2000m late in the war.

Early radar can detect you from 5-6 km.

That was mostly from my experience, and the figures may be off. If I'm wrong, someone please correct me.

[Laufen zum Ziel]

Sounds like you did very good on your own
without any advice.

[nikbear]

To be honest ppk,you did pretty much what most of us would have done,and any attack you can sail away from is a sucess,you survivedthats the problem with the wars progression and the allies advantages,getting into good positions for convoy attacks starts to get really hard,frustrating and alot of the time down to sheer luck...and most of the time ,as you observed,pointlessthere ability to detect you is so good that to have even an earthly's chance of sucess you really have to push yourself(and your crews) life expectancy to the limit,and I'm afraid for alot of the time for very little reward.I'm a big chicken Kaleun and I'm not prepared to take those chances so I get a big old TypeIX boot and go farther out to sea looking for single merchie's to sink,that way I might,MIGHT just make it to the end of the show!(He say's,stroking a rabbits foot,with crossed fingers,wearing a shamrock)

[ppk]

Haha alright then good to know I did the right thing.

Hopefully I'll make it to the end of the war ... Fingers crossed

After mid 1942 cautious is a must. I think career is too precious thing to let it be a test rabbit. If you really do DiD style. You can use single missions for that matter. And no you can't fool the radar - it really works! As for the noise underwater, try to make it as less as possible, escpecially in calm waters. Again, be prepared to let go the target if it's too far away in late war, rather than asking for lethal trouble in most cases. Smart cautiousness is not a shame, its just another way to survive longer.

[The Haint]

It's set late in the war and it starts you out being detected by Task Force's radar immediately. They waste no time coming down on top of you. I was still detected by their sonar at 200m depth.

[Jimbuna]

The potential rewards ar huge though....there is at least one Illustrious carrier out there

[Steeltrap]

The whole issue of sensor performance is a thorny one.

I believe passive detection by escorts is massively overplayed. To be effective, an escort needed to be travelling slowly in good sea conditions. They did do the 'sprint and drift' as part of doctrine, but even that relies on the sub making enough noise to be heard and then your operator hearing it.

Radar is a different issue. Early sets weren't that great, and a u-boat is a small target for a radar return. Late war radars could, in ideal conditions, detect a periscope out to about 2,000-2,500 yards.

As for sonar/asdic, the more advanced sets were effective to a maximum of 2,500 yards. From about Sept '43 it was common to encounter the sets that gave distance, bearing AND depth. They were linked to the depth-setting of dc without manual intervention. Ultimately, they could train and fire 'squid' and 'hedgehog' from the asdic 'hut'. At that point, a well-trained crew had around a 50% likelihood of inflicting damage/sinking the u-boat.

In summary:

- an escort travelling at convoy speed should have next to no chance of detecting you through passive means, in which case it really shouldn't matter how quickly you travel (the fact is the gear was overwhelmed by sea-state and speed of the escort such that it wouldn't hear any emissions from a sub). The presence of so many ships also provided massive interference, one reason why the most successful commanders got 'inside' the convoys. In short, I believe escorts should have no real chance of detecting you through passive means until such time as they are conducting a deliberate hunt without the body of the convoy being within several miles at least.

- early radars might detect you on the surface, but not outside around 6,000 - 8,000 yards. Even within that range, it would epend on sea-state and the aspect of the sub (i.e. bow on presents a very small potential return surface).

- later war radars should be effective out to a significant distance (as far as 15,000 yards?).

- asdic/sonar should never detect you outside 2,500 yards, and the earlier sets less than that. They should only provide accurate depth info from around Sept '43 onwards.

- depth charges should render passive/active detection unreliable, if not totally ineffective, for as much as 2 minutes after an attack.

- being spotted on the surface by lookouts should be notoriously difficult. There are countless examples of subs being on the surface at as little as 500-1,000 yards and never being seen, not even by escorts (from my experience, NYGM does a better job in this regard than GWX).

The real issue is working out how the sensors in SHIII work compared with this. In some respects it's better not to have in-depth knowledge of real WWII sensor performances as one is less likely to get frustrated by the simulation not mirroring known, real-world scenarios (one reason I was such a critic of SHIV was due to their failing so blatantly, and badly, in this respect)!!

Oh well - the ultimate test is what works in the sim, not what 'ought' to work!!

[kiwikapitan]

Interesting thread.

I use similar tactics to herr kaleun Schöneboom and most of the time it works although I always find the targeting period nerve-wracking. I played a late war single mission recently (the rendezvous with a small trawler) where you are up against a HUGE convoy with many escorts and I did manage to sink a medium tanker and a large freighter and thought I had escaped the destroyers and corvettes but I hadn't counted on the trailing HK group.

I left my bedroom briefly and when I returned I heard the terrifying sound of being pinged. I raised my periscope and was horrified to see a destroyer bearing down on me. I froze initially, contemplated a dodgy stern shot but then realized I was in mortal danger and tried to crash dive but got caught in a series of close explosions which tore the sub apart.

Stupid kaleun!