Historical Hunting Techniques

[BillCar]

Those of you who have read the U-Boat Commander's Handbook have doubtless noticed the recommendation of BdU to spend as little time possible underwater, and to always forgo hydrophones when it's possible to have your watch crew up on deck instead.

The longer range of the hydrophone makes me wonder why that is, exactly. Is it an issue of efficiency? Not wanting to have to dive and surface repeatedly throughout the day? I am also curious as to whether or not we know how often these U-Boat commanders followed this advice from the U-Boat Commander's Handbook.

Does anyone here happen to know what the most common methods for hunting were? I know that in Das Boot, they are also shown having the boat surfaced almost all of the time, only doing a hydrophone check once or twice in rough weather – but then, I don't take Das Boot as a perfectly historical document.

As for me, I personally enjoy having my ship on the surface as much as possible. I'll do a hydrophone check every few hours, but most of my contacts come from the watch officer shouting at me, or from intercepting a convoy after it has been radioed to me.

If we could get a discussion going in this thread about actual historical methods, as well as the preferred methods of forum members, I think it'd be pretty interesting. I found a couple of older threads on the subject of gamer preferences, but none that actually examined the most likely scenarios and techniques for actual Kaleuns. Hopefully our resident experts can weigh in, as I think it'd be very enlightening to discuss this fascinating topic!

Early war: 4 hours submerged in the morning OR evening. Which ever one keeps me from running into the blinding sun.
Example: 2 hours prior to sunrise til 2 hours after sunrise.
That covers The Daily Trim Dive, The Daily Routine (torpedo maintenance), and one hot meal for the crew.

In more dangerouse waters, and late war, I do this in both the morning and evening.
I go to 2 Knots, but don't set Silent Running, as my crew has work to do.
The Hydrophone guy does his own job, not me.
That's the extent of my hydrophone checks.
I prefer staying on the surface, especialy in transit to or from my patrol grid.

Naturaly, enemy controled coastal areas may require submerging for the entire day.

Those are my methods. If I can get away with it, I stay on the surface 20 hours per day, without interuption.

[Obltn Strand]

Historically uboats relied on vigilance of their watch crew and run more than 90% of time in surface. Coal fired ships produce(d) lot smoke which was visible for several miles. Perhaps these small squares on navigation map represent this?

[sergei]

Early War:
I stay on the surface as much as possible. Cris-crossing suspected convoy routes. I find enough contacts this way to expend all my torpedoes. Only dive to attack, or evade aircraft.

Late War:
Dunno. Never made it that far. Damn you GWX

[KL-alfman]

how much time is spent submerged or surfaced depends on:
1) what year of war
2) wheather situation
3) range of allied aircraft

when there is bad sight I stay submerged nearly all of the time and surface just shortly to charge the batteries. don't want to run into a hunter-killer-group within a range of 1,200m (as already happened to me).
I prefer the longer range of the hydrophone, too. in good wheather and marching to or from my patrol grid I sail surfaced. in the near of an allied air-base I run submerged most of the time, especially when sight is not good or it's cloudy.
don't know if this approach is historically appropriate but it helps keeping my crew and me alive.

[Panser]

Originally Posted by BillCar

Those of you who have read the U-Boat Commander's Handbook have doubtless noticed the recommendation of BdU to spend as little time possible underwater, and to always forgo hydrophones when it's possible to have your watch crew up on deck instead.

Firstly I will say that I haven't read this book, so anything I say is entirely my own opinion and/or logic, without any historical basis to back it up.

Spending as much time as possible surfaced is common sense from the perspectives of oxygen and batteries until the development of snorkels. If you're only surfacing long enough to refresh your air and charge your batteries, you could end up in a very bad situation if you're pushed back under with foul air and only a partial charge. Worse still would be if you reach the point of needing to surface and are prevented from doing so by armed merchants or warships that you happen across (or happen across you!)

The longer range of the hydrophone makes me wonder why that is, exactly. Is it an issue of efficiency?

Pretty much, yes. Although the hydrophone theoretically has a much greater effective range, the fundamental flaw is that you are relying on one man's ears for all of your external references. At least surfaced you have four or five pairs of eyes covering all angles at once. Given the use of binoculars also, in conditions of good visibility the effective range of eyeball mk.1 and binoculars is probably greater and more useful than a hydrophone. As Obltn Strand pointed out, smoke from coal-fired merchants would be visible for many many miles, even if the hull of the ship was well below the horizon. And there is one area where the hydrophone is utterly useless: Aircraft. If you're trundling along at any sort of shallow depth, especially at pericope depth, then chances are the first thing you would know about any "tired bees" or similar in the area would be massive flooding and sinking to your death.

Lastly there is range and crew comfort. Simply, a surfaced u-boat can cover a greater distance and patrol an area more effectively than a submerged one could. Remember that these were effectively surface boats that could dive, not like modern submarines that are designed to operate underwater for extended periods (or indefinitely in the case of nuclear boats, given sufficent food stores).

I don't for one minute think crew comfort was ever a consideration as u-boats were, by all accounts, pretty horrendous places to live at the best of times. Even so, the advent and use of snorkels because of the air threat must have caused a singularly unpleasant condition to live in and i'm sure the men were glad for the opportunity of a few minutes of fresh air and maybe a smoke!

[BillCar]

All good points, and I agree with the sentiment that having the boat on the surface for the vast majority of time is preferable (especially in the event of crossing paths with a ship of any kind with very low battery power – a merchant you can't attack, or a warship you can't evade).

I myself frequently detect smoke on the horizon with my binoculars, as that is how I keep track of my relative position to the enemy when flanking by day. However, I don't believe I've ever had my watch crew spot smoke – whenever I hear "Schiff gesichtet!" it's always already completely over the horizon, and about 15km away. I wonder if this is a byproduct of the GWX 16km environment or if I just have a really, really negligent watch crew.

In any case, I really wish that the watch crew spotting smoke was more effectively modeled – it'd be a big help!

[Leandros]

How the boat was run would normally depend on the tactical situation. First, there was always the stress to get to the assigned patrol area to hunt for a specific target or to join up with others in a watch line. That was the central strategy of Dønitz. The boats were to be controlled for joined efforts. During the transport stretch you didn't go under to listen for potential targets, but went as fast as you could - that is on the surface. Bad or good weather, it was expected that the U-boot lookouts would see the higher-profiled adversaries first. When radar was developed in any numbers the situation changed radically. While the boats got radar warning receivers the German development was always behind in time. For example, soon the development of British radar made the first German RWR's unusable as frequencies were changed radically. Still, the urge to make a patrol area in the best time, or catch up with a lost target by going surfaced, increased losses considerably in 1943. Much of this was due to the increased Allied air surveillance. Even in the dark with the combined radar and Leigh-light technique.

While on station, or cruising in an assigned patrol area, submerged operation would usually give better detection of approaching vessels. Particularly in bad weather. A balance of submerged/surfaced positioning would then cater for the longest endurance of crew. And I do think that point was considered. As the war proceeded more and more of the time was spent submerged - because they were forced under by the increased presence of the Allied forces. Not just because these were so many more than before but also because of their improved aids which made them so much more efficient.

As you might know U-boot operations in the Atlantic were practically suspended in May '43 due to the heavy losses inflicted by the increasingly effective naval hunting groups and Allied air surveillance. First then the "Electric" U-boats - XXI and XXIII - were developed in earnest. Even if these could have become operational in any numbers they wouldn't have solved the real problem - that of finding their targets. Only an improved cooperation and increased number of air surveillance units could have solved this. At that time of the war the resources simply weren't there.

But, that is another story.

Just thinking about "The Daily Routine" (Torpedo Maintenance).

The G7E torpedoes had to be pulled partialy out of the tubes, and serviced every day.
I would imagine this would have to be done submerged, and this was one of the reasons I chose for staying submerged 4 hours daily.

However, the G7A didn't share this drawback. I could probably do with much less time submerged early war.

(I consider the dives a nuisance, and often skip them, as they add much to the transit time.)

[BillCar]

I've been re-reading the U-Boat Commander's handbook this morning, and I am kind of amazed at how aggressive BdU was urging its submariners to be in 1943.

They want you to stay surfaced after torpedo impacts on convoys, in order to keep maneuvering and fire still more torpedos, only submerging if you are certain the enemy escorts are bearing down on you. I wonder how often THAT advice was followed. I wonder how many crews got killed trying to follow it...

[flag4]

Originally Posted by BillCar

I've been re-reading the U-Boat Commander's handbook this morning, and I am kind of amazed at how aggressive BdU was urging its submariners to be in 1943.

They want you to stay surfaced after torpedo impacts on convoys, in order to keep maneuvering and fire still more torpedos, only submerging if you are certain the enemy escorts are bearing down on you. I wonder how often THAT advice was followed. I wonder how many crews got killed trying to follow it...

...yes, it was begining to smack of Kamakasi missions, the BdU were getting desperate: Black May 1943, they got nailed with something like 41, (25% 0f operational u-boats) boats destroyed in one month + younger and younger crews - less experience - less training, it was cut back drastically. for example a 6 month course was slashed to 2-3 months. most of the experienced captains were dead or landed. i think march 1943 was one of their highest ship sinking tallies....then came May and it was all over, really, bar the dying. if you have'nt already, try reading BLACK MAY by Michael Gannon. you can pick one up from amazon - thru Subsim - for anything from 3 - 20p.