Type VIIB U-45:Combined Surfaced/Submerged Attacks at Daylight

Hello all Kriegsmarine Captains

I am going new campaign with a new Type VIIB U-45 boat now,and,in order to get best tonnage during each patrol,I do practice somewhat I intend to call "combined surfaced/sumberged attacks".

You see,most favourable conditions for making an ideal attack on the convoy usually occur when the weather is fine and there is a rather long visibility at calm sea.But,it proves very difficult to approach a convoy in those conditions as you definately have to submerge and chase the convoy submerged.

Seems I have found an answer to the sophisticated destroyer behaviour in Silent Hunter III.Destroyers AI has been mainly programmed to protect a convoy,not to let U-Boats reach a favourable attack positions,rather then attacking an U-Boat itself.

So,if you approach a convoy surfaced at full speed (let's say 19-20 knots in Type VIIB with GW Kapselgeblasse engine upgrade),avantgarde or tail destroyer spots you and starts chasing.Turn away a several degrees from the original convoy course.

Convoy starts moving away at slow pace,destroyer chases you still.

Here is a break point.Destroyer considers himself being "too far" from convoy and leaving it unprotected,turns around and accelerates to approximately 35 knots back towards the convoy.

The distance between you and destroyer is growing faster than the distance between you and convoy! Destroyer himself goes into unfavourable convoy guarding position according your U-Boat position.

Now you can chase a convoy surfaced at full speed and start maneuvering in order to shorten attack distance as much as you can and to get favourable Gyro angles for the first torpedo salvo.

When you get to this suitable for attack position you must immediately submerge to periscope depth and launch a first 4 torpedoes salvo into most valuable targets (for myself they are C3 Cargo ships and T3 tankers generally).

After a first salvo start submerging to as deep as you can at "Secure from silent mode" reloading while submerging.At the depth of approximately 200 meters start maneuvering again towards a convoy on sonar contacts in order to get favourable attack positions for the second attack.At the same time destroyers will be dropping depth charges far above you.

When you approximately 1500 - 2000 metres to convoy start surfacing at "Silent" mode,I would also recommend to pump air into Air/Water Tanks (Chief Engineer Command) to surface faster to periscope depth.But not forget to give a "Periscope Depth" command 50 - 30 metres leaving to surface,unless you are willing to jump into surface straight into deadly destroyers fire.

Repeat an torpedo salvo at the remaining valuable convoy targets turn on "Full Forward" at your engines and submerge again down to 200 metres.Leave the attack area.

This tactics usually allow to sink 5 - 6 large cargo ships and get a patrol tonnage of approximately 35000 - 40000 in a short time.So you do really spare on patrol duration and have possibilities to intercept more convoys and get bigger total tonnage during campaign in general.

I am in June 1940 now with fully upgraded Type VIIB U-45 (KDB,GW Kapselgeblasse,AFA MAK 800 Batteries) and have a total tonnage of about 230 000 tonns.

Those tactics are still working,I don't know whether they will work in later war when even more advanced destoyers and aircraft escorts will be available.

Anyway,please post your comments regarding this tactics,whether you use it or not,and what are the perspectives to use it in later war.

I will be very glad to read your comments and advices.

Good Hunting to all Kriegsmarine Aces of the Deep We will Win

[TarJak]

Interesting theory. Are you playing with GWX or another mod or just stock SHIII?

Can't say I've tried this with GWX and I'd be surprised if it worked using that mod. The AI of the escorts has been modified quite a bit and they are usually faster than you with longer range guns so I think this approach method would be very risky.

I'll give it a go in GWX and see what happens and report back.

[GoldenRivet]

TarJak this is Bdu...

Report position and status... we have been trying to contact you for several days now and we are growing quite concerned with the situation regarding your lack of communication with headquarters. Please respond as soon as possible. be aware that failure to communicate with BdU via enciphered enigma message before 1200 GMT tomorrow will result in you and your crew being placed into MIA status.

BdU radioman turns and looks at Admiral Doenitz... "sir, what was this boats last known intentions?"

Admiral "I ordered him to patrol BF12... he agreed but he kept going on and on about this new 'awesome theoretical strategy' he wanted to try... it sounded insane to me but he wouldnt listen."

BdU radioman: "Whay theoretical strategy might that be?"

Admiral: "Here it is... have a read" (hands radioman Genghis Khan's subsim posting)

BdU radioman: reads the posting "Riiight... do you think that perhaps we should skip further attempts to call Capt. TarJak, pass completely by the whole MIA paperwork issues and just call him killed in action then?"

admiral: (sigh) "Yeah... yeah i guess your right."

[TarJak]

I'm back! GR is pretty much right. My test Kaleun is now KIA with no hpe of me trying that one again. GWX DD's are NOT, I repeat NOT interested in defending the convoy that much at all and they will attack and kill you if you attempt to appraoch them on the surface.

Please take the above advice with the grain of salt it deserves unless you are playing vanilla SHIII or another game entirely.

Hello TarJack,

I am running stock SH III version 1.4 with U-Boat:Battle in the Mediterranean Add-on.

Destroyers are extremely fast,but this is not the main point.Their AI seems to have "distance from convoy" values,they cannot exceed.If they start chasing you and get away themselves from the convoy initially after some time (usually 5 - 7 minutes) of pursuit they turn back towards the convoy at twice higher speed.

Example:they chase you (as I observed at 14 -17 knots for Type "M" Destroyer) and when they are too far away from convoy initially they turn back and return to convoy at huge 35 knots speed.As a result of this speed difference they may overtake the whole convoy (if you are approaching from the tail of convoy) and open something like a surface "corridor" for your attack positions.I mean you can arrive to attack position faster with lower speed surfaced,then destoyer with his really awesome speed.

A little bit history.Type II,VII,IX boats are not suitable for chasing or attacking convoys submerged only.During real naval war of WWII they used to sprint to attack positions surfaced and attack/evade submerged.

This was the original reason of Type XXI creation.Quote from Wikipedia:

"The streamlined hull design allowed the XXI to travel faster submerged than surfaced. The ability to outrun many surface ships while submerged, combined with improved dive times, made them much harder to chase and destroy. It also gave the boat a 'sprint ability' when positioning the boat for an attack. Older boats had to surface in order to sprint into position. This often gave the boat away, especially after aircraft became available for convoy escort."

Source: http://en.wikipedia.org/wiki/Type_XXI

Moreover,have you ever heard why was PQ-17 convoy massacred?The reason of that was an order from British Royal Navy Admiralty to WITHDRAW DESTROYERS AND ESCORTS FROM CONVOY.Trial proceedings were made 15 years after the tragedy happened.

"First Sea Lord Sir Dudley Pound, after agonising for several hours, eventually made the fateful decision to scatter the convoy, reasoning that Tirpitz, with its high speed and 15 inch (380mm) guns, would be capable of inflicting massive losses on the closely bunched merchant ships."

Source:http://en.wikipedia.org/wiki/PQ-17

Naval wars theory states,that merchant convoy ships are never left without escorts.So guys,there is really something wrong in GWX's destroyers AI behaviour

[Brag]

In GWX and in the SHIII stock game I've played, surface attacks are suicidal. I wonder at what realistic settings for damage GK is playing,:hmm:

[TarJak]

I doubt that it is a fault in the GWX AI for DD's because they come at you at 20+ kts if you approach them on the surface rather than plodding along at 14-17kts which I think would be less reaslistic tahn having them race towards you as fast as they can and shooting you up.

Historically, if a u-boat was spotted on the surface the escorts would engage at speed and try to catch them before they could submerge which was the best defence for them, unless they could outrun a slow escort such as a corvette. Most DD's, DE's and Frigates were capable of more than 20kts with some later war models able to make 35-38kts.

Their job was to force the attacking boats away from the convoy and to get them to submerge where their speed and manouverability was significantly impaired.

Let's just say your tactic won't work in GWX and leave it at that eh?