Small Test of Anti Raider Warfare in 9U17

[kennonlightfoot]

I say it is a small test because to keep things simple I used the 9 months between 9/1/39 and 5/24/40 to see how the anti sub and anti surface raider warfare would play out. Only UK ships based in England were used to attack surface raiders usually in the configuration of four surface fleets attacking then the two CV based fleets for a total of six attacks each turn. This should yield conservative numbers since both sides had to go back to port periodically. For the sub warfare end, the German starts with only 2 and eventually has 4 units in the Atlantic. The average is about 3.3 subs over the time period. Since it is 39/40 the advancements have no effect. For the period covering 9 months (20 turns) the results were:

3 Surface battles resulting in Germans losing 2 CA's and 2 DD's
90 Merchants sunk.
8 Escorts sunk.
7 Sub hits (no sinkings)

Considering the Axis player can put 8-10 Sub units into play by end of 40 if they want too, extrapolating this out means:

If there is no shift in Merchant kills due to advancements, the German will be killing about 1.4 Merchants per turn per Sub unit.
That works out to some 300+ Merchants per year in later years. It also means the UK would have to build a Merchant groups (10) every turn at the cost of 100 pp just to replaces losses.

The number of escorts sunk surprised me. While not as bad as Merchant it means something else that has to be continuously replace just to keep up. Since it takes 7 months to build one, they see significant losses during 39/40 before they even have a chance to recover. This probably is the reason for doing so little damage to the subs. That means the UK player has to start building at the rate of one escort every month just to keep enough coming online to replace losses. In 39/40 they probably need to build per turn just to get enough in play by the time France falls to cover the convoy routes.

The German Sub loses were minimal. Hopefully this goes up but the only thing they have to really worry about is a Unit kill. But the Subs are relatively cheap compared to the damage they do. It is going to be harder to determine is how 1943 Subs verses 1943 Convoy Escorts will work out. But if Escort advance doesn't significantly out power sub advancement, the UK is going to have a hard time.

Surface Raider wise things look a bit more balanced. While they didn't get hit often, when they do it can be substantial. This may be enough to reduce Axis surface raiding to opportunistic. Being done only when they suspect the UK has sent to many ships away.

Since I had both subs and surface raiders out, the numbers are going to be a little high for the Sub estimate. But in 39 the Surface Raiders are missing the Bismarck and received early damage putting in back in port about half the time.

Since CV's no longer can attack Subs, the UK player is still got a serious problem in 39/40 especially considering the escort kills. By May 40 the UK only had 8 Escort still in play. When you consider UK production is only around 150 per turn in 39/40, just producing enough Escorts and Merchants to replace losses will almost require their entire production capacity. They can delay a little while since they start with an excess of Merchants and receive some as Minor Countries are overrun. But the Escort situation can't be put off.

[kennonlightfoot]

Looking at the sub warfare in the current AAR's, they seem to be confirming an imbalance between subs vs escorts. While German U-Boats occasionally attacked the escort they didn't do it as a deliberate strategy. Most escorts were much to fast and small to be hit. A search for losses to escorts turns up nothing so it probably was not a significant factor in the BoA

But it looks like the most important thing in the BoA was technology. AS warfare had major improvements over time that the subs couldn't match. In the first year of the war the U-Boats had lousy torpedoes and very short submerge times. Allied radar played hell with them as a result when it became widely available. That combined with airpower forced the U-Boats to have to stop hunting in the easier to reach areas around England. Until the long range U-Boats came on line and development of snorkels so they could avoid radar the U-Boat was checked. From 42 on the technology advancements favored the allies because AT tech was easier to come up with and implement than major advancements to the subs.

[ago1000]

You make a lot of good points here. ARe you running your test in the 1939 scenario or creating your own in the editor?

Here is a site that might interest you.

Uboats sunk by month: https://uboat.net/fates/losses/chart.htm

Allied Shipping Sunk by month: https://uboat.net/allies/merchants/losses_year.html

Really puts the BoA in perspective.

[kennonlightfoot]

You make a lot of good points here. ARe you running your test in the 1939 scenario or creating your own in the editor?

I used the 1939 scenario in 9U17. I just didn't do anything to change the balance of subs vs Escorts other than build one U-Boat so it would be available in Jan 40. Since I ran it for only 9 months their is nothing the UK can do to change the situation. It takes that long to build a Merchant or Escort. Using 39 just eliminated the effect of all the possible decisions that both sides can make to change the balance in the Atlantic.

I haven't figured a way to test how Advancements will effect the outcome in the BoA. If Escort technology doesn't give the British a significant edge over U-Boats once it advances to 41/42 levels, I don't see how the British can win the BoA. U-Boats are killing the Escorts at the rate of 1 strength point of U-Boat to 1 Escort killed. If that kill ratio stays into 1941 when the Germans can easily field 10 U-Boat fleets, the UK will have to be building 1-2 Escorts plus a Merchant fleet every turn just to maintain their forces. I doubt they can do that and maintain any other operations. The other effect of this is there will be no way to send support (PP) to Russia in 41/42.

[ago1000]

I've been running some tests too.
I've been running 9U17 also, Europe 1939 scenario modified. I run 3 groups of 3 subs. The first tests were with 0 escorts and 0 subhunters.
My results were as follows:
MMs Sunk
0 - 5%, 1 - 15%, 2 - 20%, 3 - 20%, 4- 20%, 5 - 15%, 6 - 4%, note: 7 or 8 showed up 1 with 100 attacks so 1%
I was going to run a second set of tests but was thrown a curve ball finding out that escorts may not reduce the effect of a sub attack. The tech convoy escorts should make escorts and subhunters more effective. From what I can see, the escorts and subhunters with the higher tech inflicts more damage on the subs, the end result is a drop in the MMs sunk by virtue of less subs.
I'm waiting to see how Alvaro answers a couple of questions of mine. This will help explain, hopefully what's happening.

[kennonlightfoot]

I started another test which is still in progress but has a flaw.
I used the 1941 9U17 scenario for this. What is different about this situation is both sides have their Escorts and Subs at 1941 level at start. In the 1939 scenario the UK starts at 1939 level and the Gr at 1940. Which means the Escorts will always be behind by one level or more ( because of restrictions of number of points based on year they will always lag little bit more on average).

I haven't done but two months at full strength on each side but the numbers are interesting:
8/17/41 kills: 7 Merchants, 0 Escorts, 2 Subs
8/31/41 kills: 5 Merchants, 1 Escort, 0 Subs
9/14/41 kills: 5 Merchants, 2 Escorts, 4 Subs
9/28/41 kills: 3 Merchants, 0 Escorts, 4 Subs

Sub losses are heavy when both sides at same Advancement level.
UK Escorts at 41 are Anti-Sub 1 and Defensive 2
Gr Subs at 41 are Surface 1 and Defensive 2

In 39 the numbers are UK 0 and 0 against Gr 1 and 1.
That means in 1940 the UK will be 1 and 1 against Gr 1 and 2.

I am going to run the 41 Scenario a bit long then see if I can get a better check on 39 start when it goes into 40 and 41 to see how the lag in advancement effects things. In other words, test whether the UK can ever catch up enough to not have their Merchant fleet wiped out.

[ago1000]

Sounds good.
I ran some more tests at the other extreme. The amount of escorts sunk with the higher tech drops dramatically. I would need to run another 150 more to see the numbers iron out with better averages. Will need a couple more days.

This is 45 Tech with 10 escorts in the convoy all the time and 50 attacks with full strength group of 3 subs. My results are below. Note I didn't calculate time for replacements. The subs themselves that were not at full strength were brought to a port until they were once again at full strength. It's funny, I started off with 12 groups of 3 by the end, I only had 5 groups of 3 that were completely undamaged. So it would seem that the higher tech reduces the escorts being damaged and increases the sub damage. I don't think I can conclude that there is a difference in MMs losses with the increase of escorts at this time.



Forgot to title the 0 1 2 ...8 row as strength loss in a turn. So at column 2 subs took 2 hits 19 times out of 50 attacks.

[ComadrejaKorp]

These are the mirror game numbers in progress until May 9th.

[ComadrejaKorp]

Axis attacking with 2 groups of 3 SS, it seems that up to this date the amount to invest from UK in BoA is correct.
As of this date, the results began to change a lot in favor of Axis, I have the impression that what has the greatest impact on the results are the levels of technology.

[AlvaroSousa]

A few things to consider.

#1 Sub groups are not 100% at sea 100% of the time.
#2 Raiders should be reduced now with pursuit rules
#3 The only way generated more variance, the new way flattens the curve
#4 The more the Germans invest in subs they less they have vs Russia
#5 The numbers aren't flat as before the Allies can fill all lanes the Germans can do all sorts of deceptive moves hitting other convoys that are unprotected
#6 As per #5 it also means there is time lost on moving subs.

In other words there are a lot of variables.

One game my opponent failed to build escorts or tech. In 1942 I crippled the UK and he was actually short on oil. He sill won the game because I didn't have enough vs Russia

[kennonlightfoot]

In my test nothing was done to try to evade in any way. I just put 20 Escorts into S. Atlantic. All German sub activity was in S. Atlantic. The German attempted to keep full strength only Sub units in the convoy route. Any Sub unit that took damage was immediately withdrawn for repairs. No Surface raiders were used. No other activity took place other than BoA.

I continued the test for two more months (Oct and Nov 41).
Kills were for those two months: 8 Merchants, 0 Escorts. 15 Subs

The totals for 4 months: 28 Merchants, 3 Escorts, 23 Subs

I will probably stop the test here since there an obvious trend. The Germans lose the BoA if the UK has the same Advancement level as the German U-Boats. Since this isn't the case, I will have to makeup a test based on 1939 scenario start.

Observations on the test:
With the Advancement levels equal the Escorts could easily handle the U-Boats even once they had large number of units (9 toward end).
To avoid unit losses I withdrew any U-Boat unit that took hits. This reduced the effective deployment to only 4 full strength units each turn.
The UK had to build 3 Merchant units and 3 Escort Units to make up for losses. While taking time it was below the cost to the Germans to repair 23 Sub hits.
It looked like the U-Boats were more effective (took less hits and killed more Merchants) when deployed in stacks of 3, but I did not specifically try to test that. I deployed from the same port as soon as a Unit got back to full strength. If more than one did then they moved as a stack. Usually the ratio in convoy lanes was one stack of two and two individual raiders.

Some of the assumptions wouldn't necessarially apply to a 39 based scenario since the 41 scenario starts with the UK having more than enough Merchants and Escorts to cover losses and multiple convoy lanes. I doubt these 41 results would have been effected much by the Germans trying to avoid defended convoy routes that much. Moving around a lot also reduces the chance of sinking Merchants.

The problem in testing the 39 scenario with unequal Advancement levels is both sides have other demands on Production. The German has to produce enough Subs to kill enough Merchants to cut supplies to Russia. That is where they get their pay off for commitment to the BoA. The UK has to guess at how many Merchants and Escorts they need to produce to make up losses considering the long time period between starting and getting. They also have many demands on production during the first year of the war just to survive. In 39 their Escort fleet takes a beating that they don't have a counter too. I assume if they go to close to zero the Germans will suffer no sub losses. I don't know if having no excorts affect the number of Merchants lost each turn.

[ago1000]

I don't often play as Allies and I wanted to see from their point of view what strategies they should employ.

From my test I would agree with the above comments, that the research of "Convoy Escorts" greatly reduces the sub threat for the allies over time. I am watching the mirror match of ComadreKorp vs MagicMissile and I am interested to see if and when there will be a trend downwards in losses of MMs and escorts.(Maybe 43-44ish) I'm assuming of course in both games, that the Allies have invested in Convoy escort tech to the max.
My test show that with the 45 tech, that the losses of sub to escorts is 10:1. Remembering too that these tests are done in isolation and are extreme results.

I'm not sure if this would be considered gamey, another strategy would to also try to overload your escorts in one of the convoy lanes. The 10+ escorts seem to be better at hitting subs then splitting them up. Add to the escorts the Sub Hunters and BoA just got spicier.[X(]

Forgot to mention, I haven't tested yet to see if 6 escorts + 4% from subhunters gives same results as having 10 escorts

[ComadrejaKorp]

Fantastic research work!
I give you dates that I have obtained technological advances with the UK and Germany, in case it helps you in your research.
I think it only serves to see the average time it takes to achieve them, and that if both sides maximize their research they usually go hand in hand.
The variables were many and I did not take note of how many ss attacked or sank to be able to relate it.
The numbers so far have been similar but I, as Axis, attacked with more subs and as Ally defended with fewer escorts, which seems to give the same result.
Now with the Italian fleet patrolling the Atlantic it will be very difficult to keep comparing both games.

[kennonlightfoot]

Started another test using 1939 Scenario Beta 9U17

The Germans start with level 40 Attack Subs compared to UK with level 39 Convoy Advancement. The bad part of this is the Germans will always be one level ahead and over time will usually gain a larger overlap of when they are two levels ahead. It is hard to determine how this effects combat. We know for subs that this means for the Germans during the first year their subs have Surface 5 and Defense 7. In the second year of the war it will jump to Defense 8. For the UK we don't have absolute numbers just their level jumps. In the second year their they go up to 1 Anti-sub and 1 Defense. When they get their 41 level the defense will increase to 2 but no change in Anti-sub ability.

To eliminate all external effects on the Battle of the Atlantic (BoA) the only ground actions will be for the Germans to take various countries that will add ships to the battle at approximately the typical times these things happen. Poland in Sept, Denmark in Sept, Netherland in Mar, Belgium in May, France in Jul, and Vichy France in Aug. Advancements for Convoy and Subs will be kept at maximum points. No surface ships will be used, sub/escort warfare only. All action will be on the S. Atlantic lane. No air power used at all. No other production will occur other than what is allocated to subs, merchants and escorts.

Production: Germans are limited by shipyards so they will produce a new sub whenever shipyards are available. The UK/Canada production will give priority to Escorts. Since this game essentially has unlimited production points available, the UK will produce one new Escort every month until they have at least 30 in operation (an assumption as to how many would be needed to give good coverage to the the convoy lanes). Since the UK starts with 231 merchant available they will only produce new merchants when that number drops below 230. After that they will produce merchants at a rate to compensate for losses. They may be shipyard limited though.

The UK won't be using any tactics. They will keep all there escorts assigned to S. Atlantic until they lose them.
The German's will use the following: They will withdraw any U-Boat unit that takes damage (to avoid ever losing a unit). They will try to maintain stacks of 3 units in the S. Atlantic convoy lane (this seems to be the most effective).

I start in 39 just to see how it plays out in this early period but in a real game this probably wouldn't happen to the extent it does in this test. How much would occur depends on how the new Bonus rules for DD groups work. You may not want to expose the subs to French DD's. Also, preliminary results indicate these early subs aren't in sufficient numbers to be that effective.

The UK will get the benefit of Allied defeats in this first year.
Sept 39 the fall of Denmark provides 11 Merchants and 1 Escort.
Mar 40 the fall of Netherlands provides 30 Merchants and 3 Escorts.
May 40 the fall of Belgium provides 4 Merchants.

Now for the testing!!

[ComadrejaKorp]

Remember to upgrade SS, one starts with Tech 39.
Eager to see your results, thanks for sharing.

[kennonlightfoot]

1939 was a curious year. Covering four months in which the Germans had only 2 subs to use for the first two months, then 3. They did terrible.

UK losses: 11 Merchants and 0 Escorts
Gr losses: 8 Sub factors.

Cost to the UK was actually nothing since they still had over 230 Merchants but if they chose to replace it would be just 100 PP. For the German if I am using the right calculation that would be 8 x 33 = 264.

First six months of 1940 (before France falls and Germany has access to the Atlantic ports).

Things went a lot worse for the UK. I assume this was due to the Germans being able to keep more stacks in play as their number of sub units increased from 4 to 6 and averaged about 5 during this time.

UK lost 42 Merchants and 5 Escorts.
Gr losses were 14 sub factors.

For the UK this represents about 620 production points (I didn't try to include production lost from losing ships carrying it).
For the Germans this was 462 PP.

The Germans aren't doing great but they aren't doing as bad as 39 where they were almost losing a sub for every Merchant. But if they are going to win the BoA they have to have a better kill ratio than that. But I expect that to happen because it wasn't until they had 6 sub units in play that they were able to consistently keep two stack, one of three and one of two subs, in the convoy lanes every turn.

Also at toward then end of this six months we see the German Attack Subs advance to 41 on 5/10 and the UK Escorts advance to 40 on 6/21.

The UK shipping is in good shape with 224 Merchants at the end of June. However, the Escort production is lagging. They are down to 15 Escorts (that includes French) with 9 Escorts on the reinforcement track. I strongly suspect the UK needs to maximize Escort production much earlier in 39 to be able to handle what is coming. Since I restricted combat to S. Atlantic we won't see this in this test unless the UK Escorts start taking heavy casualties.

[ComadrejaKorp]

Curious result, it seemed that it would be the opposite.
Naval subfactors repair costs 25% of the original cost.
1 subfactor SS tech 39 = 6 pp
1 SS tech 40 subfactor = 6.6 pp (I think it rounds up and still costs 6 to repair)

[ago1000]

I also caught up on some reading of old forum questions:

Phase 1) subs attack first and escorts do not have an impact on the results.
Phase 2) escorts attack subs (10+ seems to be the ticket)

The decline of sinking of MMs occurs as escorts damage more and more subs.

It was an interesting read especially some of the strategies others suggested(older versions) was to hold back the escorts until they got their tech level up. So the addition of sub hunters may in fact help escorts now to create more damage in the second attack phase. Harrybanana brought it to my attention that the number of escorts does not impact the amount of MMs sunk.

https://www.matrixgames.com/forums/tm.a ... ey=escorts

@ComadrjaKorp
(6.6 = 6) I think it truncates the result. Most calculation I found drop the decimal at the end.
I'm not sure that I understand how you are calculating the 6 PP or what you mean? Sorry. Did you mean:
25% of 120(original cost) = 30 PP
upgrades are 10% of original cost so each upgrade is 12 PP

@kennonlightfoot
Re: 1939 poor show.
Could be some bad luck too. There is a lot of randomness.

Experience has shown that groups of 3 subs have better luck in the long run than 2 or 1. Like most, not exactly sure if calculations are one lump sum when grouped or each group still attacks the MMs separately.

My assumption is separate attacks and mathematically it looks something like this:
Let's assume subs have a 1 in 10 chance of hitting an MM, then it follows it has a 9 in 10 chance of missing.
Therefore a group of 1 sub has 90% chance of missing completely on it's attack. (ie: absolutely no hits)
a group of 2 subs has an 81% chance of missing completely
and a group of 3 subs has a 73% chance of missing completely.

This is great everyone. Thanks. My understanding of the sub system has greatly improved. Now I need to sit down and try some strategies.

In the past, did subs need one OP point to attack a convoy lane? This doesn't seem to be the case for subs or sub hunters any longer. Also I noticed that on turn 1, the Axis get a free sub attack before Allies can place escorts in their lanes. Just wondering if this is new?

[MagicMissile]

Yes I am pretty sure you get an attack now even after spending 2 op. And as I understand it the attack comes immediately at the start of the allied turn so there is no time to place escorts. Possibly that should be changed someway.

I also noted in my game with ComadrejaKorp that if you close a convoy line and remove all the escorts from the closed line then when you want to open it again you cant deploy any escorts as the route is not active. So in the Axis turn if the axis player doesnt sleep he will get free attacks on the reopened line.

[malkarma]

ORIGINAL: ago1000

@ComadrjaKorp
(6.6 = 6) I think it truncates the result. Most calculation I found drop the decimal at the end.
I'm not sure that I understand how you are calculating the 6 PP or what you mean? Sorry. Did you mean:
25% of 120(original cost) = 30 PP
upgrades are 10% of original cost so each upgrade is 12 PP

120 is the cost for a brand new submarine with 5 streght points. So each sub point= 24PP
Since repair is 25% of initial cost, a sub strenght point(24 PP) will be 24*.25= 6PP