ASW damage from AC

[heibernt]

From time to time i get a OP report stating Catalina attacking a japanese SS at XX, japanese SS is reported hit. Alot of these reports are probably FoGs, but how much damage can i excpect in ones that actually hit? Minor, yardtime or sunken subs?

[jeffk3510]

If they're attacking your ships, you should be able to see the ship on the screen, and determine from there.

If it is your planes attacking their ships, and the ship shows up in the ship loss screen, keeping FOW in mind, you can assume it might be sunk. Other than that, you can't..

[heibernt]

Thx for the reply. Yea i know i can only find out via the ship loss screen, but i was wondering what kind of typical dmg such an attack would cause. Will the sub still be operational, or does it have to return to port, or will it likely sink on the way home? Im just wondering so i might be better able to evaluate his sublosses, and thereby there presence in my shipping lanes.

[Lokasenna]

In my IJ game against the allied AI, I've lost 2 subs to 500-lb. bombs off the west coast. In deep water, too. I have a better grasp of detection level mechanics and such now...

This came up in another thread recently. Usually, ASW aircraft aren't very effective at actually damaging subs. Where they succeed is in raising the DL. I see that ops report message all the time, but I figure that maybe only 1 in 50 actually represents a successful attack. Especially from Catalinas...though that could just be a result of their longer range. I believe the IJN subs that I lost to ASW aircraft were to SBDs.

If you actually manage to hit a sub with a 500-lb. bomb, it's hurting. Noticed that from the above losses as well as several port strikes in various games - one decent bomb hit typically results in boom/glug-glug.

[Chickenboy]

ORIGINAL: Lokasenna

In my IJ game against the allied AI, I've lost 2 subs to 500-lb. bombs off the west coast. In deep water, too. I have a better grasp of detection level mechanics and such now...

This came up in another thread recently. Usually, ASW aircraft aren't very effective at actually damaging subs. Where they succeed is in raising the DL. I see that ops report message all the time, but I figure that maybe only 1 in 50 actually represents a successful attack. Especially from Catalinas...though that could just be a result of their longer range. I believe the IJN subs that I lost to ASW aircraft were to SBDs.

If you actually manage to hit a sub with a 500-lb. bomb, it's hurting. Noticed that from the above losses as well as several port strikes in various games - one decent bomb hit typically results in boom/glug-glug.

I've lost a small handful of subs to Allied ASW air attack-Catalinas. 500 lb. bombs did the trick.

It's difficult in the game as it was IRL to get a sub kill with an aerial bomb. From Clay Blair's Hitler's U-Boat War (Volume 1): a 500lb. bomb needed to land within about 10-15 feet of a surfaced submarine to cause lethal damage. Very difficult to do IRL.

So, OP, I'd assume that 75% of the "sub is reported HIT" messages are FOW. 25% are probably real. Most 500lb. (or 250kg bomb) "hits" (probably near misses IRL) will cause some pain requiring repair of the submarine. Rarely will you get an outright kill.

In order to increase the likelihood of a hit (or damaging near miss), trained bomber or patrol crews with an ASW rating of 70+ are advisable. Airframe weapon used is important too. A 500lb (or 250kg) bomb will do more damage than a 100kg (or 250lb) bomb, as you might imagine. Thus, select the best balance of airframe, range, ASW skill, altitude (<2000ft.) and co-ordination with other forces (ASW H/K groups, naval search, mines, etc.) for best effect.

[John Lansford]

The problem of hitting a small half-submerged sub from a fast flying patrol plane was solved in mid-1943. Bombs on a B-24 patrol plane were fitted with forward facing rockets. When dropped, the rockets fired, countering the forward momentum of the bomb and allowing it to drop nearly vertically. The B-24 would drop three bombs with each attack, nearly insuring that the sub would be bracketed by the bombs and getting a hit.

I don't know if that innovation was ever put widely into use but it was invented and tried, apparently with some success in the Atlantic. I would think that rocket armed patrol planes were also more effective in damaging subs than just dropping bombs on them. After all, a hole in the sub's hull means it is no longer a submersible, and fairly easy to detect afterwards.

[dr.hal]

One of the defenses of a sub IRL is early aircraft detection and thus time to dive quickly. So I would assume that the lower you search altitude the higher the probability of a hit or near miss. Given this I quite often put some ASW air assets on 100 Ft altitude at two or four hex range. But I've not played enough to confirm that this hypothesis is accurate or not. I would like to think that at 100 Ft the aircraft has a lot better chance of catching the sub still on the surface and thus improving its chances of success. But I'm not sure.

[heibernt]

ORIGINAL: Chickenboy

So, OP, I'd assume that 75% of the "sub is reported HIT" messages are FOW. 25% are probably real. Most 500lb. (or 250kg bomb) "hits" (probably near misses IRL) will cause some pain requiring repair of the submarine. Rarely will you get an outright kill.

I put all my catalinas in Pearl on asw with a 7 max range on the second turn of a GC game. Now I got a ton of subsighting every turn and a report of around 5 hits every turn. If only 75% are fog, that means im hitting one sub every turn. That seems alot. I think my unexperienced pilots are overestimating there own marksmanship. Any specific reason you belive fog is 75% and not more? Even hitting a sub every 2nd turn seems alot..

[Chickenboy]

ORIGINAL: heibernt

ORIGINAL: Chickenboy

So, OP, I'd assume that 75% of the "sub is reported HIT" messages are FOW. 25% are probably real. Most 500lb. (or 250kg bomb) "hits" (probably near misses IRL) will cause some pain requiring repair of the submarine. Rarely will you get an outright kill.

I put all my catalinas in Pearl on asw with a 7 max range on the second turn of a GC game. Now I got a ton of subsighting every turn and a report of around 5 hits every turn. If only 75% are fog, that means im hitting one sub every turn. That seems alot. I think my unexperienced pilots are overestimating there own marksmanship. Any specific reason you belive fog is 75% and not more? Even hitting a sub every 2nd turn seems alot..

I'm talking for good (70+ ASW skill) pilots. I've got no idea what reporting rate ASW scabs have, as I'd not waste my time in using them. These are rough estimates.

[spence]

Of the 759 U-boats lost in WW2 250 were sunk by aircraft alone with another 37 sunk by a combination of both ships and aircraft. The larger part of the submarine losses attributable to aircraft occurred in 1943 and later. In addition to patrolling where the uboats actually constituted a threat the a/c drove the uboats down (underwater) where they often lost contact with the convoy. Thus merchant ship losses went down at the same time uboat losses went up.

IT SHOULD BE NOTED THAT ASSIGNING AIRCRAFT TO "FOLLOW CONVOYS" IS NOT POSSIBLE IN THIS GAME EXCEPT IN SO FAR AS A CONVOY STAYS WITHIN THE ASSIGNED ARC OF ASW.

In large part this was the result of two factors:

1) the Allies began to escort convoys with Very Long Range B-24s
2) the Allies began to heavily patrol the Bay of Biscay which was a "chokepoint" between the French bases of the uboats and the convoys.

According to Combined Fleet the IJN lost a lower percentage of submarines to aircraft. In part this may be because the I-boats patrolled much further from Allied airbase. A significant number of IJN sub losses resulted from SIGINT which allowed Allied subs to ambush the IJN as it sortied.

[alanschu]

It's also possible that the hits are ones that only land close and cause maybe a few points of system damage.

[crsutton]

I would guess that only about 10% of reported hits are actually hits. The rest are FOW.

[John Lansford]

I wouldn't put ASW search planes at 100' altitude. They may get more hits but their search pattern will be very small, and the pilots' fatigue and crash rate will go way, way up really fast. If you want them to get the best hit chance, set them at 1000'. I set mine at 5000' and they find lots of subs and get a few hits. IMO it's more important to sight the subs than actually hit them from a plane; once they are spotted the ASW ships can jump on top of them fairly easily.

[Oberst_Klink]

John got a point; as long as the pilots are still rookies -70EXP it's better to use them to spot the subs, increasing therefore the DL and let some ASW skippers blow' em out or at least prevent them from attacking.

Klink, Oberst

[dr.hal]

ORIGINAL: John Lansford

I wouldn't put ASW search planes at 100' altitude. They may get more hits but their search pattern will be very small, and the pilots' fatigue and crash rate will go way, way up really fast. If you want them to get the best hit chance, set them at 1000'. I set mine at 5000' and they find lots of subs and get a few hits. IMO it's more important to sight the subs than actually hit them from a plane; once they are spotted the ASW ships can jump on top of them fairly easily.

John you are right, it does wear out the pilots. But there are things that you can do to mitigate that impact yet still get good results. If the squadron has 18 aircraft and about 22 pilots, put it on 50% ASW search at 100' and keep it close to shore... this would then become a sub no go zone. And it can be maintained almost indefinitely. I found this to be an excellent use of the Wirraways which I'm hard pressed to find another use for!

[John Lansford]

Are the B-25D1's good ASW planes if you set them at 100'? Every time I assign them an anti-airbase mission they drop down and strafe anyway, so I'm wondering if they do that in ASW mode too.

[inqistor]

It is worth to remember, that ANY training at 100ft will train Strafing. So even when whole groups is making ASW any percentage of training will NOT train ASW.

ORIGINAL: John Lansford

Are the B-25D1's good ASW planes if you set them at 100'? Every time I assign them an anti-airbase mission they drop down and strafe anyway, so I'm wondering if they do that in ASW mode too.

I do not think it is normal attack. According to Devs only ASW skill is used, so DB probably also do not make dive attack, and no plane is making skip-bombing.

[spence]

Actual ASW AARs and attack photos by about 100 British, Canadian, and American a/c are to be found at:

http://www.uboatarchive.net/Uboatlist.htm

There exists a video of a PB4Y-1 attacking a U-boat (the quality of the video on my laptop is very poor - I think it has something to do with the settings on it since I saw it clearly on my old desktop). The a/c is at several thousand feet initially but drops down to 100 ft(-) to make the attack. In tis video and apparently routinely the machine gunners on the plane fired to suppress the flak. If one reads some of the "Reports of Interrogations of POWs" one finds that strafing by multiple .50 calibers inflicted significant damage on some of the uboats.

[HexHead]

How about depth charges? Libs made great ASW platforms. Do the Allies get DCs for the air?

The primary result of air cover is forcing the sub down, though, even optimally.

[Bullwinkle58]

ORIGINAL: heibernt

Thx for the reply. Yea i know i can only find out via the ship loss screen, but i was wondering what kind of typical dmg such an attack would cause. Will the sub still be operational, or does it have to return to port, or will it likely sink on the way home? Im just wondering so i might be better able to evaluate his sublosses, and thereby there presence in my shipping lanes.

In the game my limited experience has been a typical 500lb/250kg bomb strike on a sub will generate between 30 flooding and 95 flooding. In most cases system damage is in the 40-60 range. Some engine damage. There are many randoms involved. I do not recall an "off screen" sinking of a sub by air ASW in a first attack. Not saying they can't happen.

In every case it has happened to me I have needed to send the boat home to the yards. If flooding is over 70 and system in the range 40-60 there is an excellent chance it will not make it. If flooding is in the 50s with that system damage it has a fair chance if speed is reduced to Cruise.

In my experience that's the envelope more or less. Your results may vary.