Snorkel detection by airborne radar

[Marcello]

My experience with patrolling in 1944 is that at least until mast mounted RWR will become available I am forced to keep the stealth meter and use it as an ersatz RWR, otherwise getting bombed by aircrafts is pretty much guaranteed even with a very conservative snorting regime (one ten minutes run in daylight to renew oxygen supply and 60-120 minutes at night to recharge the batteries, in one or two runs and always at slow speed).
From what I understand snorkel was considered a life saver (though far from being a sure thing detection by visual or radar was possible) but running surfaced with sail mounted RWR and a good watch crew seems a competitive alternative in the game.
The impression I get is that there are perhaps less aircrafts in the air looking for subs than in real life but with better snorkel spotting capabilities (which might be a reasonable game compromise, after all the number of ASW assets on patrol at any given moment must have been huge at such late date).Is this just perception?
I am running GWX 3.0, Commander and Hsie patch. I am in admittedly hot areas, AM51 or AM52.

[Sailor Steve]

The impression I get is that there are perhaps less aircrafts in the air looking for subs than in real life but with better snorkel spotting capabilities (which might be a reasonable game compromise, after all the number of ASW assets on patrol at any given moment must have been huge at such late date).
I think the game, even supermodded, still has many more aircraft than real life. It's a very big ocean. Part of the problem is that radar isn't essential to spot a schnorkel. On a clear day a submarine at periscope or schnorkel depth is clearly visible from the air.

[Randomizer]

My experience with patrolling in 1944 is that at least until mast mounted RWR will become available I am forced to keep the stealth meter and use it as an ersatz RWR, otherwise getting bombed by aircrafts is pretty much guaranteed even with a very conservative snorting regime (one ten minutes run in daylight to renew oxygen supply and 60-120 minutes at night to recharge the batteries, in one or two runs and always at slow speed).
From what I understand snorkel was considered a life saver (though far from being a sure thing detection by visual or radar was possible) but running surfaced with sail mounted RWR and a good watch crew seems a competitive alternative in the game.
The impression I get is that there are perhaps less aircrafts in the air looking for subs than in real life but with better snorkel spotting capabilities (which might be a reasonable game compromise, after all the number of ASW assets on patrol at any given moment must have been huge at such late date).Is this just perception?
I am running GWX 3.0, Commander and Hsie patch. I am in admittedly hot areas, AM51 or AM52.
Snorkelling in the GWX world is very doable, it just takes patience rather than the stealth meter. Also there are non-radar equipped aircraft (Mosquitoes, Beaufighters, Avengers and Martlets) that can kill you and will not trigger an RWR warning.

To survive in the SH3 snorkel world:

Turn Map Contacts ON.

Snorkel only from the Navigation Map screen zoomed to the 2500 metre scale (one square = 500 metres).

At least one periscope must be raised at all times when snorkelling. It does not appear to matter which periscope although generally the Sky (Observation) scope was manned by a lookout at all times. Having both scopes raised offers no advantage but does increase the likelihood of having both destroyed. Then you're in trouble.

No more TC than x8. On clear days or after you get fitted with the mast-mounted RWR going to x16 is possible but dangerous. Snorkelling is an exercise in patience.

Watch the map display closely. Aircraft will appear on the map as moving triangles and even a x8 they are moving Very Fast. If you spot one, set TC to x1, get the mast and periscope down immediately, crash dive and make a radical turn towards the incoming plane if practical. This often results in the depth charges landing safely behind you but is the worst target aspect if the plane is equipped with Stiebler's homing torpedo.

If using Steibler's FIDO Mod, you become very vulnerable should the attacker drop one since you're making lots of noise and you generally will not have the luxury of identifying the type of aircraft. If you hear a splash but no explosion, start thinking FIDO, switch to Silent Running and reverse course to put your boat between the torpedo and your screws. If your're still alive in 10-minutes, resume normal operations.

Once attacked by aircraft, clear the datum since GWX may spawn attack groups from nearby ports that can come out and investigate. If you have no hydrophone contacts in 4-6 hours, it should be safe to snorkel again.

Many SH3 users have issues with corrupted games that were saved while submerged but almost all of my careers are late-war, saved while submerged and I do not recall having any bad saves or lost careers since implementing the protocols below.

When saving in SH3 while submerged:

TC x1 or pause before saving;

Never save at periscope depth, when snorkelling or with a periscope up;

Never save in contact with the enemy. Allow 1-2 hours of game time to pass before saving after an air contact;

Never save within 50-km of any port (I use the compass tools to draw 50-km circles around all the ports in my area of operations s I know where not to save);

Always save in the Control Room screen (I do not why or even if this is relevant but since I started consciously doing so I have never lost a save. It may just be a placebo though...);

Always wait at least 30-seconds to 1-minute after making course or speed alterations and running any TC > x1 before saving; and

Never overwrite a previous save, each save should be unique.

Have fun snorkelling in SH3 and Good Hunting.

[Marcello]

Thanks for the tips.
Generally I have always left the observation persiscope up. In some cases I tried to run the periscope watch by myself but actually spotting aircrafts before it is too late seems to be pretty hard (as no doubt was the case IRL) and it gets pretty tedious, even for the short daylight snorting run (lookouts were changed often IRL). I usually keep TC at 16 or less when running snorkel and looking at the map but I seldom zoomed real close.

[U1260]

Thanks for the tips Randomizer, I've been wanting to do a late war career but the issue of saving games submerged held me back. In fact when I first got the game I had saved some games submerged and had no problems, but reading here in the forum that many did I stopped doing it. Most likely I was doing what you recommended without knowing it.

[Randomizer]

A couple of unsolicited comments on snorkel techniques in GWX 3 follow.

There are a number of schools of thoughts regarding when to snorkel. Boats working the vicinity of the British Isles are always under threat and need to use extreme care when snorkelling but if you're careful, the main threat in the patrol area ceases to be aircraft but becomes surface ships and mines, the former probably summoned by aircraft. This is actually pretty accurate historically and may very well be something of a tribute to the GWX Team in getting the historical balance correct.

A snorkel patrol is essentially conducted in two phases, the transit to and from the patrol area and the patrol itself. There does not appear to be any hard and fast snorkel doctrine and Commanders seem to have been pretty much left on their own.

When transiting submerged you basically have two choices, snorkel consistently in the absence of any threats or proceeding fully submerged, snorkelling one or more times per day to recharge and air out the boat. Using the former you should be able to cover 150-200 km per 24-hours but running at 3-knots and snorkelling only twice per day reduces this to 70-90 km in 24-hours. With the distance from Bergen to the North Channel some 1400 km this means that once you decide to proceed submerged it may take a long time to reach station. Snorkel patrols were generally less than 50-days and a Type VII might have a ration endurance of perhaps 55-60 days. I plan 50-day patrols with a 10% (five-day) fudge factor.

Once on station, you can snorkel when required whenever it is safe to do so. Patrolling at 1-2 knots preserves your battery but airing the boat once or better yet twice a day is a good idea. Before you get your mast-mounted RWR in September or October, daytime provides the best time since you can see aircraft coming. If using H.Sie's hydrophone fix, you will not hear surface contacts so the historical technique of shutting down the diesels every now and then and listening is a good option. Otherwise your hydrophone operator will advise when a ship is detected and drop your TC to x1. Even with Map Contacts ON an aircraft will not drop your TC and you have to do so manually. Not sure how this works for those using the stealth meter.

I generally start thinking about battery charges when the box gets down to 90% but this is a captaincy decision and there's no "right" answer.

I spend most time when not snorkelling at about 25-metres, at this depth the crews can use the heads and Cookie can dump the gash down the BOLD tube.

Often you will detect contacts but the geometry will be wrong for an interception. My loadout generally consists of and Gnat or Falke, a G7E III Electric and two FaT's in Tubes I-IV and a Falk/Gnat in Tube V with an electric reload. Reloads are usually 2 x FaT electric, 2 x Fat air and 2 x G7E III forward and one aft. Launching a pair of Fat's into a convoy from outside the screen is sometimes effective and done with minimal risk. Save the air torpedoes for night operations, convoys may have air cover and I would swear that the planes in GWX can see the torpedo wake.

Boring in at speed makes noise and drains your battery so weigh the risks vs benefits. Having only hydrophones and occasional short looks through the periscope often means that you may lack the big picture and even with Map Contacts ON, hunting in 1944-45 is a challenge.

If you're careful and reasonably conservative in pursuing contacts your biggest fear should be mines, a threat that the GWX Team was not shy in deploying around British waters. If you use the external camera, you can see and avoid them. I don't and so have had several promising late-war careers terminated in a minefield.

What did the Real Skippers do?

Much of what data out there is contradictory which might indicate that it was left to the individual commanders, as noted above. One of the snorkel pioneers was KL Karl-Heinz Marbach of U-953. In Harald Busch's U-Boats at War he discusses his snorkelling experiences and tricks and I have pretty much adapted these in SH3 and they are explained above in game terms.

Herbert Warner in Iron Coffins writes as if he invented many of the U-Boot Waffe's snorkel techniques but given that he inherited U-953 from KL Marbach in August and probably the best snorkel-trained crew on the Atlantic at that time; like many aspects of Werner's book, this seems unlikely.

Probably the most successful snorkel boat commander was KL Hartmut Graf von Matuschska in U-482. On his first patrol he sank four merchants and an escort for 32,621 GRT. All the merchants were in convoys when sunk, an incredible feat in August and September 1944. U-482 was at sea for 42-days and spent some 37-days submerged. KL Matuschka was killed on his second patrol when U-482 was sunk by aircraft in the Shetland-Faroes gap.

KL Graf von Matuschka (http://www.uboat.net/men/commanders/796.html)

KL Marbach (http://www.uboat.net/men/marbach.htm)

Good Hunting

[Marcello]

Generally my experience is that aircrafts are still the greatest threat but it should be noted that I am running in a XXI and I am only attacking merchants sailing alone or in pairs in a relatively busy area. I am not actively pursuing convoys yet and steer clear of warships. I make sure I still have 75/80% battery charge even after I have put some distance from the sinking ships and I seldom use bottled oxygen, so I have plenty of both in case I get chased by surface ASW assets. So far it has happened only once and shaking them off has been relatively straightforward, though i must say watching Hedgehog in action is scary.

[Albrecht Von Hesse]

I'm not sure why this works, but the technique I use seems effective.

There are only two times I use the schnorchel: 1) to refresh the air (which is quick), and, 2) to recharge the batteries (definetely not quick!). And in both cases I do not move at all. I carefully trim until any wave action ocassionally closes off the schnorchel valve and then I just wait.

So far I've never been attacked doing it this way.

I have a quick question, however: I have map contacts off. Does having the beobachtungsperiskops raised actually permit my AI personell to detect aircraft?