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Axis & Allies Europe 1940» Forums » Variants

Subject: Submarine destroyer interaction rss

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Justin Royek
United States
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Dear BGG and AA community of gamers,

I have decided to make a variant pertaining to destroyer-submarine interactions, that would in my opinion better reflect submarine warfare in World War II as seen in the Axis & Allies game.

The current rules say that having a destroyer present negates a submarine's first-shot stealth attack.
This is unrealistic because many submarine captains could sneak up undetected from enemy destroyers guarding a convoy because of a method called "silent running"

Silent running is a method where submarines run as quietly as possible to avoid detection by enemy destroyers. Submarines often used this is the North Atlantic to avoid being detected. Most of the time, a destroyer did not know a submarine was there until a ship in the convoy was hit and/or sinking, then something was going on for sure.

But the game does not allow for submarines to utilize their silent running capabilities when dealing with enemy ships with a destroyer was present, when World War II submarine skippers were able to sneak up into a convoy even though a destroyer was present because the sensors on the destroyer cannot pick it up because the sub is silent.

For example, an account by a US submariner in World War II.

It happened on the submarine USS Puffer when it was rigged to "run silent, run deep" to avoid detection by a Japanese destroyer. Everything was shut off -- air conditioning, refrigeration and fans. "Anything that would make noise and betray us to the enemy was shut off," said the Mount Kisco, N.Y., native. To maintain silence, the crew stood in water a few inches deep from condensation, walked around in stocking feet and ate with their hands.

The rule that says that a submarine cannot submerge with a destroyer present is foolhardy because any sane submariner would submerge their boat when a destroyer is attacking them to prevent their boat from being blown to bits. This rule goes against common sense in relation to submarine warfare and allows you to be blown to bits by a destroyer. This is like a rule that says that you cannot go prone on a battlefield because a sniper is present or something like. It's absolutely ridiculous that your submarine cannot submerge when a destroyer is present!

This goes against one of the fundamental elements of submarine warfare. To submerge when under attack by an enemy destroyer. To take him on the surface is suicide because you'll get rammed and or blown to bits.

Another rule that submarines cannot fire at air units is also inaccurate because submarines of the period traveled mostly on the surface as their batteries did not allow them to travel for long periods of time underwater. These are not nuclear submarines we are dealing with in this game that aren't equipped with AA guns.

Submarines shot down air units attacking them during the war. For example, a submarine at Pearl Harbor shot down a Japanese Zero during the surprise attack on Pearl Harbor.

My new rule will allow destroyers to roll after a submarine fires it's first shot attack.

Submarines and destroyers will fire first before all other naval units will do so.
The attacker or defender must fire their submarine's first shot attack first. Then any attacking or defending destroyers roll.

The defender has 2 destroyers, one rolls a "2" a hit, the other a "3" a miss.

The attacker's submarine's 5 submarines fire like this. 3 submarines roll a "2" a "1" and a "3" 2 hits and 1 miss and the other two roll a "4" a miss and a "1" a hit. Any hits incurred from a first-shot attack by a submarine and a destroyer's depth charge rolls are sunk also.

Destroyers often left their convoys to attack submarines that were sighted after sinking a ship in the convoy. The other submarines in the pack were able to sneak past these destroyers because the enemy destroyers were distracted with the other submarines in the pack, which enabled other submarines to attack other ships in the convoy and sink them, which caused losses among ships in the convoy. The British had few destroyers early in the war to counteract U-boats.

Destroyers were not designed to defend against enemy submarines, they were designed mostly as fleet escort ships or to hunt down enemy torpedo boats. The name destroyer comes from the designation of the ship's role as a torpedo-boat destroyer. Destroyers were usually not designed to take on subs. However a new class of ship was called a destroyer escort or DE as it was known. These were ships designed to take on enemy submarines.

They had sub hunters like corvettes, not the car though. They had hunter-killer groups that were composed of destroyers and carriers. The destroyers had sonar to hunt enemy subs. Sonar did not always detect a submarine because the submarine's were

The rule that a destroyer always detects a submarine, is therefore unrealistic because it goes against the real capabilities of sonar systems, which can only detect a submarine if it makes any noise.

I will also allow submarines to move into a sea zone occupied by a destroyer during non-combat phase because no combat is going on and submarines are using their silent running capabilities to inhabit sea zones inhabited by destroyers. Submarines were often able to move into sea zones inhabited by destroyers because of their stealthy silent-running capabilities and the minimizing of noise made by the boat.

You'd have to pretty suicidal to not submerge when a destroyer is attacking you.

Destroyers usually didn't attack submarines until a ship in the convoy or task force was hit and or sinking. Submarines could conduct sneak attacks against enemy destroyers.

Submarines could always sneak into a sea zone undetected if a destroyer was present because of silent running, which enabled them to be undetected. This makes more sense in the game to equip submarines with silent running capabilities.

I am going to make it so that a submarine's first shot strike is not negated by a destroyer and submarines can transit through sea zones inhabited by enemy destroyers to another hostile sea zone. When doing this, a submarine does not have to stop and conduct combat with a hostile destroyer in a hostile sea zone.

If a sub goes through a sea zone with a destroyer, just like an air unit goes through a hostile territory with an AA gun in it, a destroyer will roll a die roll for the destroyer. The die roll is a standard "2" or less for a standard destroyer's die roll. This is to simulate destroyer attacks on subs.

In World War II, German U-boats were able to travel through the Straits of Gibraltar into the Mediterranean, through sea zones inhabited by British destroyers. The cunning tactics of the German U-boat skippers (Herr Kaleuns as they were known) and silent running, enabled them to sneak past the ships guarding the Straits into the Mediterranean to submarine bases at La Spezia to assist their Italian brothers in arms in the Mediterranean and sink British shipping there.

The idea that subs have cannot go through a sea zone inhabited by a hostile destroyer goes against the historical realities of naval submarine warfare. Submarines were often able to sneak in undetected. A submarine can choose whether or not to do combat in a sea zone with a hostile destroyer.

Air units can attack submarines with a destroyer present. Air units routinely attacked submarines without a destroyer present at night because they had radar. The radar enabled them to see in the dark. Another thing I will add is that air units can attack submarines without a destroyer present if their nation has radar capability technology.

I am going to allow air units to attack without a destroyer present because submarines mostly traveled on the surface at this time. The rule saying that an air unit cannot attack a sub without a destroyer present makes it seem like submarines of the World War II period travel underwater all the time. This makes submarines like the nuclear submarines of today that travel purely underwater, which is unrealistic as submarines mostly traveled on the surface because of their limited underwater endurance as their electric batteries did not permit them to stay under for a long time.

Air units frequently attacked submarines without a destroyer present. Especially long range aircraft, like the Short Sunderland flying boat or the PBY Catalina, which often detected submarines traveling on the surface because a guy in the airplane had a pair of binoculars during long hours of sub patrols of boring mundane work. When a periscope was spotted or a surfaced submarine, they would go into attack. It didn't matter if a destroyer was present or not. Air units will coordinate with destroyers when attacking submarines though. The destroyer's roll will be enhanced. When air units attack with a destroyer present, their capabilities will be enhanced like a tank enhances a tactical bomber's attack roll to a "4" or less.

Many navies had dedicated anti-submarine warfare (ASW) aircraft dedicated to hunting enemy submarines. They often attacked without a destroyer present because the submarines they often spotted, attacked, and sank often traveled on the surface to charge their batteries or were cruising on the surface. Submarines in World War II cruised on the surface.

Many U-boats were sunk by patrol aircraft out at sea.

Hudsons began to receive ASV radar in early 1940, and were assigned specifically to antisubmarine duty beginning in August of 1940 from Aldergrove, Northern Ireland. In March, 1941 No. 269 Squadron began operations from Iceland. One of the Hudson's first successes against U-boats was on August 27, 1941, when an Iceland-based Hudson bombed and damaged U-570 and, after repeated strafing passes, observed the U-boat crew to surrender. The Hudson circled the U-boat and called additional aircraft and ships to the scene. U-570 was indeed captured intact, although the crew had thrown the Enigma machine and codebooks overboard. Hudsons went on to achieve two dozen additional successes against U-boats. An Africa-based RAF Hudson of No. 608 Squadron was the first aircraft to sink a U-boat with rockets.

Sunk without a destroyer present.

I will make a new rule that says that when attacking a submarine with air units, the destroyer's attack role will be boosted by a "3" or less because the destroyer's capabilities are being boosted by the use of aircraft attacking the submarine. Air units no longer need to have a destroyer present to attack submarines.

Destroyers did not always detect enemy submarines. The idea that a destroyer magically detects a submarine goes against the realities of naval warfare.

Submarine detection by destroyers was a hit or miss affair as spotting with sonar was not always precise because subs could use tricks like putting on some noise for example to "give away" their position and then disappear, which would give destroyers the false impression that a submarine was there, when in fact it wasn't and the submarine had evaded detection.

Sonar was primitive back then and could only estimate the depth of a submarine, not give its exact depth and it could only get so close. Depth charges were often set to an estimated depth and often exploded at an estimated depth based on earlier readings and estimations and exploded at a pre-determined depth, which enabled them to escape because they could hear the depth charge explosion and dive deeper and a destroyer's screw noise or propeller noise often obscured sonar readings because the screws created noise that often hid the submarine contact. The screws of the destroyer often obscured contacts.

Many aircraft were shot down by enemy submarines during the war. Submarines did indeed fire back at air units. The Germans even had an order that said that U-boats had to shoot back at aircraft.

In return the U-boats shot down at least 28 aircraft (with many more severely damaged). This is important since many works on the subject give the impression that the RAF victory over the bay in 1943 had been almost free.

U-155 14 Jun 1943 Aircraft attack, aircraft shot down:
Polish Mosquito HJ648 (307 Sqdn RAF/B, pilot S/L S. Szablowski)

At 09.29 hours, four Mosquito aircraft (3 from 307 Polish Sqdn RAF and 1 from 410 Sqdn RCAF) attacked a group of 5 outbound boats (U-68, U-155, U-159, U-415 and U-634) in the Bay of Biscay. The leading Mosquito first strafed U-68 and then U-155, but its port engine stopped after being hit by AA fire and the aircraft was forced to make a belly landing back at the base in Predannack. A second Mosquito, piloted by F/O J. Pelka, attacked too but its guns did not fire and the remaining aircraft did not attack due to the intense AA fire.

Many aircraft were shot down by submarines during World War II. The idea that submarines cannot fire at air units is completely wrong and ridiculous because subs had AA guns to shoot back at aircraft and often did shoot down and fire at air units.

An example of how a U-boat slipped through the screen of destroyers and sank the carrier, USS Block Island.

On 29 May 1944, U-549 slipped undetected through the screen of the hunter-killer group TG 21.11, formed around the USS Block Island (CVE 21) and fired at 20.13 hours three T-3 torpedoes on the carrier, one or two of them struck and caused her to sink northeast of Canary Islands.

U-boats slipped through destroyers undetected. Destroyers usually responded when a ship was hit or a torpedo was fired from a submarine, detected by the ship's sonar.

I am going to make it so that only a destroyer can fire after a submarine does its first-shot attack.
No other naval units, other than a destroyer, may fire back at a submarine after its first-shot attack.
Destroyers can still be selected as casualties after a submarine's first shot attack. After they are hit and after they've rolled, they are sunk and removed from play, along with any other vessels hit during a sub's first shot attack.

Audacity's fighters sighted a submarine, 22 miles from the convoy, which is beyond the range of destroyers. The Martlets or Wildcat fighters attacked the submarine with a destroyer present, but the presence of the destroyer did not cause affect the air units ability to prosecute the submarine, nor did the air units have to attack with a destroyer present, even though they did.

My new rule allows for air units to attack submarines regardless of whether or not a destroyer is present. Air units can still attack submarines with a destroyer present.
U-131 fires back, an example of a submarine firing at air units, and shoots down one of the attacking aircraft.

A submarine can still submerge if a destroyer attacks with air units present. I will add that too.

Admiral Doenitz wrote.

"The worst feature was the present of the aircraft carrier. Small fast, maneuverable aircraft circled the convoy continuously, so that when it was sighted, it forced the boats were forced to submerge or withdraw. The presence of enemy aircraft also prevented any protracted shadowing or homing procedures by German aircraft. The sinking of the aircraft carrier is therefore of particular importance not only in this case, but in every future convoy action."

Any carrier aircraft present with a carrier also attack the submarine after its first shot attack.

It goes like this. Submarine fires its first shot attack, then any destroyers that the attacker or defender possesses along with any carrier aircraft attack the submarine. Any ships hit by the submarine are removed from play and any subs hit by the destroyers are also removed from play.

Then all other ships roll their die rolls as if it were normal combat.
Phases go like this.

1. Attacking/defending submarines fire first (first-shot attacks). Any of the attacker's or defender's destroyers or air units roll next after the submarine conducts its first-shot. Any casualties incurred from these moves are removed from play. Air units may be selected as casualties, as the submarine can shoot back at air units and is using its AA guns to protect itself from aerial attack.

Ships other than destroyers may be selected as casualties. Any ships or air units hit are removed from play.

2. All other naval units that survived the first-shot attacks or depth charge attacks on the submarines roll as if it were regular combat.

3. Repeat as necessary until A. the submarine submerges or withdraws or B. the attacker's units are all destroyed or C. The defender's units are all destroyed or D. Both attacking and defending units are destroyed at the same time.

Tactical bomber's attack roll is boosted to a 4 or less when a submarine is present to simulate the use of Focke Wulf Fw 200 Condor aircraft that attacked convoys or ships with U-boats present. Condor maritime patrol aircraft attacked convoys with U-boats present and were such that CAM ships and were a significant threat to convoys that the Royal Navy had to deploy carrier airplanes to stop Condor attacks on convoys. The Condors were a threat to convoys early in the war. Tactical bombers are boosted by a submarine now.
This only applies for the attacker. Tactical bombers are not boosted on defense.

A destroyer's roll is not boosted on defense either. If the defender has a carrier and aircraft and the defender has a destroyer, then the destroyer's die roll is not boosted to a 3 or less. It is just defending the convoy and or task force anyway.

The destroyer is doing its convoy protection or escort roll. This special technique of the destroyer shall be called a "fleet defense" roll. This fleet defense option is only exercised after a submarine has fired its first-shot attack and incurred any casualties.

In most cases during a convoy attack with destroyers escorting it, the submarine fired first and its stealth capability was not negated, in fact boosted by the fact that the submarine was able to sneak in undetected to the convoy or fleet in question and sink some ships. The submarine's stealth attack is actually being boosted and/or used to good effect when a destroyer is present. When a submarine attacks ships with a destroyer present, it uses it stealth attacks anyway.

So, the idea that a submarine's stealth attack can't be used with a destroyer present goes against the very role and the very way that submarines work in real-life tactics. Destroyer-submarine interaction does not work the way it is presented in the game. Submarines use their stealth attack when destroyers are present, it doesn't matter if they are because whether or not they are there is irrelevant, to achieve maximum surprise.

A submarine uses its stealth first-shot attack when a destroyer is present in that sea zone to prevent it from being detected and/or blown to bits by the destroyer. The roll afterwards simulates a depth charge attack by destroyers in response to a submarine attack, which is more realistic based on the actual accounts of submariners that attacked convoys during the war and the actual capabilities of a destroyer's sonar systems.

So, I changed it to better reflect actual real-life capabilities of ASW Anti-Submarine Warfare tactics.

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