[Bosje]

Before I continue, some clarification may be in order. Steamwake, I tried to explain that there are records of gunfights with escorts but only as a last desperate measure after the boat was forced to the surface. The game allows it, as it should allow it, but the player should not attempt it except as a last measure in a hopeless situation. Many mods will support this behaviour (you'll die) while the stock game does not (you may survive), the point of this thread is to provide thoughts on historic happenings as my sources describe them, compared to various approaches to the game. From my sources it seems that the escorts DID pound the subs with the main guns but only AFTER it was forced to the surface, to finish them off.

I am writing this because I myself had many many questions as I started to play both SH3 and SH4 on higher 'realism'. I was blown away by the level of immersion which I got from playing with supermods on 100% (90% ext.cam.) and I found myself wanting to know just exactly how things happened for real, and how I could implement that knowledge in my gameplay to enhance the experience. Basically this thread attempts to summarize the many lessons I learned and am still learning.


This may turn into a longwinded manual but I hope it doesn't, lol. Carrying on:


Submarine of submersible torpedo boat? Surface operations.


Most of you will be familiar with the notion that these WWII subs are nothing like the modern day nuclear hunter-killers and boomers, not even anything like the modern day diesel-electric subs although they work in much the same way. Your basic method of propulsion is the diesel engine and your usual condition is 'surfaced'. Free after the German Uboat handbook: The boat is designed to operate on the surface, being a fast and highly maneuverable torpedo attack boat. During daylight attacks and for purposes of remaining undetected and evading the enemy, the boat has the capability to fully submerge. It should be noted that, while submerged, your boat is restricted in it's ability to move and to detect the enemy.


It is that last sentence that struck me, when I read that handbook. The SH series has always invited me to dive and do a hydrophone check to see if any ships had entered my area of operations. Any data on the technology insists on ranges of up to 20 or even 30 kilometers (throw me a bone on the nautical miles). But from what I'm reading they considered the watch crew's eyes a much more important sensor than any bit of kit on the boat. There you have it and it is actually confirmed by 'Das Boot', the official Kriegsmarine Manual and some books on Dutch submarine warfare in my possession. They relied on their lookouts to spot the enemy and even when they spent the day submerged for fear of enemy attack, there was a watch on the periscope to look out for smoke on the horizon (and aircraft). In 'Das Boot' they only dive to listen for contacts when the weather is so bad that nothing can be expected to be seen. The translation goes something like: 'In this [crappy] weather we can hear more down here than we can see up there.' On US fleet boats you have the benefit or SD radar (aircraft detection) and if you stick your conning tower up a bit, even SJ radar (surface contact detection) to help you with getting contacts, but all the same, the submarine was mainly a surface vessel. What to do with this bit of information? Well, it seems that the 'crappy sonar guy' is in fact quite true to history. Anyone who does not do his own manual hydrophone checks is rather 'realistic'.

But it's still a sub, yeah? No worries, you are indeed in command of a sub. A typical procedure was to spot a ship or group of ships (convoy), get an initial idea on their speed and course and then outflank the contact on the surface. After gaining an edge on the target by setting up ahead of it, doctrine stated that you submerged to close in for the kill. During daylight this is common sense but even during the night, this was the standard procedure. Accounts from early operations mention a sense of 'great daring and cool-headed thinking' on the part of those U-boat commanders who ignored the rules and went in for the kill by attacking on the surface under the cover of darkness. Later, this became the standard but it was 'invented' by the early aces. Whatever else can be said about your boat, it is a very small thing indeed, even if it is a comparatively huge US fleet boat, and a lazy lookout is quite unlikely to spot it. Another interesting observation is that the target was looked at from low angles, against the background of the horizon and the night sky, while the sub was looked at from the much higher positions on a tanker or freighter, as such blending in with the murky darkness (and ever shifting shapes of the waves) of the sea itself. At this stage I personally feel unhappy with the stock game and most mods which tend to take away the ability to call 'smoke on the horizon'. I've been confronted with merchants on evasive maneuvers long before my watch crew actually yelled 'ship spotted' but that is just a personal gripe. The more important thing is: how do we deal with surface operations?


Range: your boat has no range on electric propulsion. Even if the batteries support a speed of 1 or 2 knots for a day, it doesn't get you anywhere. You cover your ground on the surface and you keep a sharp lookout. Diving is something you do several times a day. At least once. This is the 'trim dive' and it serves to check on the boat's submerged handling and depth changing/keeping. (Technical information on how submarines actually worked is extremely interesting and I learned a fair bit during the past months but I know that many people out here will be able to explain it much better than I possibly could.) Either way, while you are down there it does not hurt to do a hydrophone check, of course. Getting anywhere at all is still done on the surface, with your diesels. And you dive on contact with surface ships and aircraft, determine whether you are going to intercept or not and you move on.


Each his own, of course, and this applies to the real deal as well: Kretschmer (greatest German ace) had a standing order on his boat that the officer of the watch was NOT allowed to initiate a crash dive upon visual sighting of a ship, especially at night. Kretschmer, then, went against the rules by realizing that his boat was unlikely to be spotted, even by a warship, at the time when his watch crew spotted that (war)ship. He tended to get more information on his target while on the surface and he usually went through the entire engagement without ever diving. Only if he was found out, as proven by a destroyer's bow charging straight at him, did they crash down into the deep. In fact, there is an account which describes his capture in the spring of 1941. It says that his watch officer made the mistake of crash diving on sighting a ship, before waking up the commander. The destroyer heard the noise made by the diving boat and before anything could be done, Kretschmer found himself in a boat wrecked by depthcharges, blew ballast and abandoned ship.

So for a realistic approach to gameplay there are many options: spend most of your time on the surface if you want, or spend any daylight hours submerged for safety. Attack with bravado from the surface, at night, or do all your sinkings from periscope depth. Run with decks awash to lessen your profile or rely on hydrophones to keep an ear on situational awareness. Surface operations give you range and good eyes (depending on the game setup) and you can go looking for targets. Submerged running will keep you safe but you'll have to wait for the targets to come to you. Again, radar tends to unbalance this later in the war and the commanders had to re-invent their tactics. This is also where you find a real difference between German and US operations. It seems that eyes were considered the primary sensor on the boat, but if hydrophone checks get you your beloved targets then by all means go for it. This is where things get interesting, referring to the fact that realism is in the mind of the beholder:


Even if the real guys did not get those lone merchants by hydrophone checks, it feels like a very professional and 'ace' thing to do in the game. Killing those ships after hunting them down from that initial far-away whisper on the hydrophone is one of the main perks of the game (in my opinion). Who cares that I don't really have any accounts of that happening historically? (Even I find it hard to believe, if anyone HAS got numerous accounts of subs hunting mainly by hydrophone, please share.)


Pull the plug! Submerged operations.


'Pulling the plug' is a lovely bit of vernacular, mainly from the US subs, I believe. It means to dive the boat. Diving quite literally involved pulling the plug on the main ballast tanks: big containers on the outside of the pressure hull which had vents on the top- and down sides. When the boat was surfaced, these tanks contained air. When all vents were opened, water was allowed to flow into the tanks from below as the air was expelled on the top. Basic physics tell us that this decreased buoyancy and it caused the boat to sink (in a controllable fashion). Inside the boat are stored reserves of compressed air. If you close the top valves but keep the low valves open and then force this compressed air into the ballast tanks, this will force (some of) that water out again. That will increase buoyancy and the boat goes up. By messing around with the buoyancy you can make the boat go up and down a bit and that is how you reach your desired depth. From there, the depth keeping is mainly handled by the diveplanes which work much the same way as ailerons on aircraft wings, water flowing past the diveplanes will make the planes have an effect on the boat's angle, allowing you to propel yourself upwards or downwards or to level out and maintain your depth. Steep diving (crash diving) means you allow the tanks to fill completely with water while moving at top speed in a downward angle. That will make the needle on the depthgauge shoot down quite rapidly. Blowing for surface means the opposite: Forcing all water out of the tanks with compressed air while moving at full speed on an upward angle, causing the boat to pop up to the surface like a cork. If you run out of compressed air, you are in trouble. If you run out of submerged propulsion, you are in trouble. If you run out of both, you are lost. (Correct me if I'm wrong about any of the above here, please.)


The game does not model this to my own satisfaction. You can spend all day submerged, changing depth casually, you can sit still at 85,5 meters depth all day without moving an inch, etc etc etc. That is not how it worked but hey, let's work with what we've got. For purposes of immersion you should always maintain some speed while submerged, to cause the diveplanes to have an effect. One knot does the trick without causing you to make too much noise or to run out of juice any time soon. 'Surface the boat' would historically involve using some of that compressed air to empty the tanks which is not featured in the game. (You can spend all day at any depth at 0 knots, order the boat to surface and it will zoom up there without any trouble, compressed air still at 100%. This could only have happened if the crew were manually pumping all that water out of the tanks.) Ah well, I just order a 'blow ballast' when I want to surface.


Free from the 1950s US submarine manual: When the boat does not respond during a dive and keeps on going down there are several steps that can be taken to arrest that seemingly uncontrollable dive. In order of severity:
-Cut the engines. This will cause the boat to stop propelling itself down while the boat is at a downward angle and should slow or completely halt the descent. If it fails, the next measure is to:
-Order a full speed reverse. If the boat is still at a downward angle, this will cause the boat to pull itself back up, quite literally. If this, too, fails:
-Blow all ballast, use compressed air to drastically increase buoyancy.


This actually worked in SH3 (at least it worked in GWX 2.1) and I fail to understand why SH4 does not feature such basic principles on submerged operations, but either way I hope this gives you some idea on how the boats actually got out and about in the cellar. The hulls were built to maintain a constant pressure (equal to that on the surface) for the crew and at depth, this means that the sea is exercising an incredible pressure on the hull. The boats were built quite well and could withstand quite a lot but one should always be aware of the dangers of going deep. (The yard guarantees 90 meters but we can also go deeper.) Many Skippers/Kaleuns have gone to great depths in order to evade depthcharge attacks, both for real and in the game. Personally I find this aspect of the game among the most interesting and appealing features. There is nothing like it. The hunter hunted, cat and mouse, a battle of wits, 'Jetzt wird es psychologisch, meine Herren', you spend several hours in real time, inside the control room, listening to the destroyers above you and trying to stay alive, trying to stay one step ahead of them. Brilliant. But I'm drifting a bit now, let us get back to basic operations:


After having lived through a depthcharge attack, or after diving away from that air attack, or after diving for any other reason, sooner or later you will surface again. Oxygen runs out after about 40 hours on most boats, batteries run flat and you're not getting anywhere while you're down there. So you surface. If you want to approach this realistically, here is how they would do it (from the German handbook, also featured in 'Das Boot', after the convoy attack):
Hydrophone check at shallow depth, listen all around you to make sure there are no screws churning around anywhere near you. Then proceed to periscope depth, do a quick scan around without zoom, to make sure you are not being ambushed by a destroyer, sitting there 100 meters off your stern, engines stopped. (I never actually witnessed such a thing but I'm always thinking how cool it would be to actually find your periscope view completely filled by a lurking destroyer, lol.) Then, do a more careful scan of the horizon all around you by zooming in and slowly making a complete turn with the periscope. Then surface, the commander goes out onto the bridge alone or with his first officer (strikes me as odd to risk both senior officers, but anyway) and make sure there is really actually nothing at all anywhere around you. Then call the 'all clear' and proceed to surface operations.