Convoy Attack Bug?

[kklemmick]

I'd noticed this a while back and wasn't sure if it was a bug or an intentional design decision, but subs can attack twice on the North Atlantic convoy route if resources are being shipped to multiple targets. I've not really played with it much, but I do know a lot of players ship oil back to Canada in order to utilize the Canadian DD, which allows the Germans to get two attacks on UK convoys which can completely throw off the Battle of the Atlantic.

I mention this now because in my game with ncc1701e I'm getting two attacks with each group and I don't think he realizes this can be avoided by eliminating these additional convoy routes. Note the report below (from a trial hotseat game BTW, not my game with ncc1701e) where the same sub group attacks both a UK Convoy route and a Canadian one:

Convoy.png (63.6 KiB) Viewed 716 times

I believe this also happens when shipping to the USSR, and so in some cases you can get 3 attacks per group on a given convoy route (I've not verified this, but I recall seeing this before).

This makes no sense to me where a group gets only one attack against a route shipping 100 resources, but gets another full attack against a route shipping something like 1 oil. This is why it seems like a bug to me.

I also feel like the randomness of these attacks is just way over the top. I've been destroyed sometimes even with full escorts and sub hunters, while other times I've seem the Germans take a beating with nothing there. It really feels like you have no control over the situation.

For WP2, I'd suggest increasing the effectiveness of the attacks based on the number of resources being shipped, and adding these resources together for all routes before doing the rolls. Personally, I'd also like to see less randomness, but that's of course a matter of opinion.

What do others here think?

[Nirosi]

Hi,

Yes it ca happen to all lanes, it is one attack per convoy (country to country). So up to three in the Arctic (US to USSR, UK to USSR and USSR to USSR when they need to use the sea for the Persian oil). My guess is that NCC1701e probably knows about it as it has been playing for a while. If not, he knows now however

Shipping oil to Canada can be useful but not that much since a country will stop exporting oil if it falls to zero oil to replenish its pool. So Canada never stays more than a month with no oil.

I like you proposition for WP2 as it makes it easier and streamlines the rules. But for WP, right now I find that the BOA seems very well balanced for two players that are taking it seriously, even with the double attacks (it has become part of the balance now).

It is true that the results can be very random, but for me (simply a personal preference), I like it actually. Extremes do happen in war quite often. And for the BOA, there were months in the real war when u-boats could barely find any enemy ship (11 in April 1940) and then other months when they almost sank a whole convoy with 12 ships in a single day (PQ-17)!

[canuckgamer]

A friend of mine who is playing the Axis tells me that he has moved subs 46 hexes and they still get two convoy attacks. This means they are not under the same rules as other naval units where if you even move one hex you can only make one attack or if you move 25 hexes you cannot make an attack. I think this should be changed so subs are the same other naval units.

In regards to variance in attacks on convoys we too have experienced wild swings. I would be very interested in seeing the CRT for subs attacking convoys and escorts attacking subs.

[Nirosi]

If you "double move" with subs, they will not attack as well (they "usually" sink between 0 and 2 MM in that case). Moving once (24 hexes IIRCl maybe 23?) or not moving at all does not however seems to make a difference.

Not allowing subs to raid after moving their full move will again unbalance the BOA (way in favor of the UK). And it took many patches to finally have something that feels right. It seems to me that what is important is the forest not the tree. In other word, over the course of a game, are the actual mechanics leading to a realistic result and to a competitive BOA? I honestly think it does despite the wild swing in results and the double convoy attacks. It is strange to say, but sometimes by wanting too much a realistic tree, the forest can become "wrong".

PS: Lets also not forget that surface ships (including CVs) can move 48 hexes and still attack (pursuit attack) but not that well either.

[kklemmick]

I am all for seeing the forest for the trees, and I don't think the current balance is way off overall; I DO think however, calling out that at present subs get one attack per destination country (not per convoy, because you can see a lot of different convoys going to the UK, but still only one attack) is how it works, so that players can make decisions on whether that convoy is worth it or not. At present it's not clear how that works without some experimentation. Secondly, this is a strategy game, not a simulation, so making the choices players make MATTER is really critical in order for it to be fun. This is why I think the randomness and the feeling that the UK's choices don't matter are a problem.

For shits and giggles I set up two different Head to Head games where I did nothing but the sub war. One I did absolutely NOTHING with the UK, not even sending out escorts, the other I had 10% sub hunters and max escorts the whole time. In both cases Germany maxed their sub production. In the case the UK defended, they used fleet oilers to get 100% coverage over all turns. Germans made no attempt to evade the sub hunters, so this is absolutely the best effort the UK could make.

Here are the total statistics:

No escorts, no sub hunters, starting 1939 through Jan 1941:
173 merchant marine losses, 0 escort losses, 0 sub losses

Full escorts, full sub hunters, same period:
173 merchant marine losses, 20 escort losses, 43 sub losses

So that means, the UK actually lost MORE by making an effort, although did manage to cause about 1.5x those losses to the Germans, which would be considered a win - but keep in mind this is absolutely the BEST outcome you can expect, taking into account the randomness in the game of course.

So to me as a UK player this really feels like my effort is pointless. And yes, I realize with 2 data points this doesn't prove much. I'm guessing the UK player got pretty lucky in the no-escort case.

I think this could be improved with no gameplay changes at all, if there was more transparency in the reports, such as:
"The 10 escorts on the North Atlantic route prevented 3 merchant marine losses and cause 1 sub loss. The 10 sub hunters caused 3 sub losses."

That would show the player exactly what the results of their escorts and hunters were doing, and could allow them to decide whether those hunters were worth the oil or not, for example. This kind of information can make the game FEEL much different without tweaking the balance at all.

[Nirosi]

Hum.. I agree that if those numbers are representative there is a problem. The UK should not lose more by... trying. But did you try it a few times?

I ask because I find from my experience (and I played both sides quite a few times) that those UK loses are quite high when actuality trying. Even against a German player serious with u-boats, I would be quite disappointed to lose so much so early as the UK. I do not say it never happened, but my felling and experience is that is it in the high end for loses. However the 43 u-boat loses do seem high on the other side (so this is indeed probably close to the max the UK can do for that aspect at least)

The best I ever did with the Germans (with 11 U-boats or so) was 690+ MM and 40+ or so escorts (and still lost the game ), but that was from 1939 to 1945. And on the other side, as the UK, by 1942 when maxing escort and tech, I always start to see U-boat sinking (and usually they do not come back). For that aspect at least, I think, the difference will be made. Not investing means German U-boats at max until 1945, investing means there will be less and less. But I agree that a difference should be seen from start, doing or not doing something against the U-boats should also make a difference in 1939-41

I do not know if you have enough time for a few more test with same parameters, as to be able to confirm those numbers, a larger sample is required? Or maybe a small group of volunteers where we each try it 2-3 times to see?

[stjeand]

DO NOT forget this works in both ways.

In 43 and 44 the UK can set up random convoys all over to get double and triple attacks on subs.
Sending 1 MM with 10 escorts will cause more damage to Uboats than you will lose since at most you will lose one MM and maybe an escort.

The multiple attacks does not bother me overall.

Better for the Axis early then 43 it swings the other way.

[kklemmick]

I do not know if you have enough time for a few more test with same parameters, as to be able to confirm those numbers, a larger sample is required? Or maybe a small group of volunteers where we each try it 2-3 times to see?

Yeah, unfortunately I probably won't find the time to do this. My 2 runs took about 30 minutes, so it's not terribly hard, but I'm really short on time these days.

I do suspect that my samples were probably outliers. I honestly can't think of how I did the same damage when the UK made an effort since I had to pull my subs back to repair, but the numbers are the numbers I got with my quick and dirty test. What it does show is that there is enough randomness in the process that making an effort or not is not clearly a win for the UK. I have save games for these if anyone is interested to take a look.

Not to complicate matters more, but I also think the 1940 scenario is completely broken from the Battle of The Atlantic perspective. In this scenario Germany starts with EXACTLY the same number of subs in queue and on the map as in 1939, but the UK has 355 MM and 22 escorts compared to 205 MM and 12 escorts in 1939. That means the Germans are nearly a year behind in sub production, but the UK has more MM and escorts than they could actually have built while playing the 1939 scenario, even if that's all they focused on. The one 1940 game I've started as the allies, I literally never built a single MM or escort because Germany was never going to get enough subs to threaten me. Granted, if the Axis player made an effort I'd need to respond, but the point is the UK starts with such a huge advantage it's completely off balance IMO.

As to stjeand's comments; I admit I've not had the opportunity to play through to the end on all but one game, so it's hard for me to see how the long term effects play out. I will say though, lacking that knowledge (which obviously new players will), I don't see investing in the sub war from the UK side as being a clear win. I do think simple messaging changes like I suggested could help with this a bit, while not actually impacting gameplay.

I have noticed, the few times I lose a sub it's because of a double attack. If a damaged sub takes 2 hits from each attack it sinks, so these days I pull my subs back to repair if they are even mildly damaged.

[stjeand]

For me early on your want to keep your convoys to a minimum...basically 1 per route if possible.

Once you have higher tech you can start with multiple convoys going to Canada and from US to UK and USSR and UK to USSR.

You can get 3 attacks on subs which in 43/44 will normally sink at least 1 or damage quite a few so they have to return for repairs.
Early on your just have to be more cautious...

I have even shut off my convoys from time to time to reduce damage...but that is fairly rare and only if the Axis had crazy good luck.

[Nirosi]

Hi again all,

Not sure if they are all relevant to the actual discussion, but here are some things I have noticed/done (with my own bias of course) over the last 2 years for u-boats:

• 1939 tech escorts are very fragile. There was even a time when I was not escorting convoys until they hit 1940 tech as I felt I was losing more than gaining by escorting (which indeed would be strange for a game). I have changed that now and I escort convoys from start again, but sometimes I still wonder.
• I never put less than the required escorts per MM (for all practical purpose, it means 10). I have noticed that the loss rate for escorts is too high if some are missing. I prefer 10 escorts and 0 escort (in two lanes) rather than 5 and 5. (and I prefer 15 and 0 rather than 10 and 5).
• Escorts do not directly protect MMs (confirmed more than once by Alvaro). They only do so by damaging/sinking subs. So, if one ever sees a result where subs sank some MMs but got no damage in the exchange, it means by definition that the escorts had no impact whatsoever on that result for that turn/battle.
• When using surface units, we see two steps (search attempt and then, if found, battle). However, for convoy attacks, something happens under the hood that reflect those two steps. Maybe they are also done in two steps, or maybe a formula just mix them together. But that could explain the high range of results we see. This high range also happens in surface battle once we include the search part.
• Three u-boats is the way to go. Sending only groups of 2 or 1 will results in a very easy BoA for the UK as the u-boats will last much less longer.
• Always max research for convoy escort tech for the UK, doing less invites trouble if Germany is serious with subs. I also always make sure to have at least 30 escorts by the end of 1940, ideally 35 for spares and be ready for 40 when the USSR is at war (and buy a few MM early on just in case). If Germany is not serious with u-boats some of that investment will sadly end up been a waste, but the risk is too great not too.
• If Germany is serious with the BoA, buying MMs must become repetitive (up to once every two turns maybe in the heat of the battle). Yes, it costs a lot, but no doing it may cost more latter.
• Everybody has it own risk tolerance. As the Germans, mine is 3 steps for U-boats. At 4 step they stay and raid, at 3, they come back for repair.
• Sub hunters are only a relatively small (sometime moderate maybe) cherry on the Sunday. Escorts are the real u-boat killers at sea.
• Strategic bombers with detection and electronics could be a good investment (depending on your style). Not as much for the sub-hunter bonus, but for direct strike on u-boats in range. They become a little efficient with 41 tech and quite OK with 42 tech. When not needed, they can convert to strategic bombers. 1939 tech is short range and not efficient at all. 1940 tech is good range, but still not efficient enough yet.

[ncc1701e]

I think that Strategic bombers with detection and electronics should contribute more to sub-hunter bonus. In game, they are bad at attacking subs at sea. Whereas in reality with air to sea radars, they were deadly.

In the game, this is not reflected enough.

[stjeand]

I think that Strategic bombers with detection and electronics should contribute more to sub-hunter bonus. In game, they are bad at attacking subs at sea. Whereas in reality with air to sea radars, they were deadly.

In the game, this is not reflected enough.

That depends on how a damage to a U-Boat in a convoy lane is determined.
It could be said that when u-boats are damaged it may be air or sea that actually perform the hit.

Air did little until 1942...then air did the majority of the sinkings and late in the war it was mostly ones sunk in port.

[Nirosi]

Alvaro did mention at one point that CVEs are part of convoys and highers convoy tech include their use. So air from land based is for us to do it (strategic with detection/electronics or any other planes in range) while air from CVEs is included in the convoy battles.

[stjeand]

What the game can't reflect is the 1000s of sorties flown by individual planes that may or may not spot / attack a sub.

So for me...when a sub is damaged, I presume that it could have come from an Escort, Aircraft or even a mine.

[ncc1701e]

Still bombers, with the right tech level, are not sinking a lot of subs.

[stjeand]

Still bombers, with the right tech level, are not sinking a lot of subs.

I don't feel they should sink a lot by direct attack...

They should be enhancing the convoy escorts more...and not really fly a mission to sink subs.

Though I cannot remember the exact numbers, I think that the % should be higher based on tech level.
Something like 39 1%, 40 2%, 41 3%, 42 4%, 43 4.5%, 44 5%, 45 6%

[ncc1701e]

Still bombers, with the right tech level, are not sinking a lot of subs.

I don't feel they should sink a lot by direct attack...

They should be enhancing the convoy escorts more...and not really fly a mission to sink subs.

Though I cannot remember the exact numbers, I think that the % should be higher based on tech level.
Something like 39 1%, 40 2%, 41 3%, 42 4%, 43 4.5%, 44 5%, 45 6%

This is indeed what I have said earlier. Strategic bombers with detection and electronics should contribute more to sub-hunter bonus.