A25.33 American OBA Draw Pile for Scarce Ammunition

[bendizoid]

Cool beans. Rich mentioned that on an episode of the 2HS last year. Didn't know he had completed them. Any idea if they can be downloaded from anywhere?

Good question. I asked him in a text. As a matter of sport I usually extend the option of the Pleva rule to any opponent with OBA.

 

[bendizoid]

Cool beans. Rich mentioned that on an episode of the 2HS last year. Didn't know he had completed them. Any idea if they can be downloaded from anywhere?

They might be in the next Journal.

 

[The Purist]

Can someone explain the rationale for NOBA decreased accuracy due to heavy surf? I would think the ships providing NOBA would be at least 1000 yards from the surf line. Should it be heavy seas? Thanks. Captain Bacchus is also curious.

The only thing I can think of is that the heavy surf may denote heavy swells out in the comparatively shallow water off shore where the ships lay for fire support. Pitch and roll may effect a cruisier or destroyers fire at the relatively short range that the ships are firing at (a few thousand yards at best).

Just skylarking but I'm not sure the analogue fire control 'computers' of the larger ships were accurate enough to correct for pinpoint accuracy required to put an FFE within 100m of the aiming while the ship is moving at low speed and being effected by the motion of the sea.

 

[Actionjick]

The only thing I can think of is that the heavy surf may denote heavy swells out in the comparatively shallow water off shore where the ships lay for fire support. Pitch and roll may effect a cruisier or destroyers fire at the relatively short range that the ships are firing at (a few thousand yards at best).

Just skylarking but I'm not sure the analogue fire control 'computers' of the larger ships were accurate enough to correct for pinpoint accuracy required to put an FFE within 100m of the aiming while the ship is moving at low speed and being effected by the motion of the sea.

Not sure either but appreciate your educated guess or speculation if you like.?

 

[T34]

Please elaborate.

Essentially, the house rule OBA system will result in one less fire mission per module than the new system on average for a standard Soviet Draw pile.
The more cards in your draw pile, the less you lose.

This is because, as seen above, you are adding a red card every time you draw a red, reducing your percentage chance of getting a black card every time you draw red. With the old system, the first red you draw increases your chances of getting a black by more than 10%. But with the new system, it drops by about 10%. These are cumulative and if you look over all the possibilities, you see that on average, the Red Army draw pile drops by an average of one mission per module.

 

[von Marwitz]

The Iowa fired 16 inch shells to clear 200 yard wide LZs during Vietnam. WWII battleship @ 900 foot long. All things considered would not want to be on the receiving end.

While this would surely be able to blast anything in that area, could it actually 'clear' it?
Palm trees, building rubble or whatever might have been there before needs to fall down somewhere. In fact, all over the place, which might not make it easy to get across - at least not for vehicles of any sort.

von Marwitz

 

[Actionjick]

While this would surely be able to blast anything in that area, could it actually 'clear' it?
Palm trees, building rubble or whatever might have been there before needs to fall down somewhere. In fact, all over the place, which might not make it easy to get across - at least not for vehicles of any sort.

von Marwitz

Wasn't there but will speculate that the LZ was cleared enough to allow the helicopters to hover a few feet above the ground so the troops could jump out. Just an educated guess.

 

[Actionjick]

The only thing I can think of is that the heavy surf may denote heavy swells out in the comparatively shallow water off shore where the ships lay for fire support. Pitch and roll may effect a cruisier or destroyers fire at the relatively short range that the ships are firing at (a few thousand yards at best).

Just skylarking but I'm not sure the analogue fire control 'computers' of the larger ships were accurate enough to correct for pinpoint accuracy required to put an FFE within 100m of the aiming while the ship is moving at low speed and being effected by the motion of the sea.

We need input from a Gunners Mate.

 

[BattleSchool]

Essentially, the house rule OBA system will result in one less fire mission per module than the new system on average for a standard Soviet Draw pile. View attachment 14673
The more cards in your draw pile, the less you lose.

This is because, as seen above, you are adding a red card every time you draw a red, reducing your percentage chance of getting a black card every time you draw red. With the old system, the first red you draw increases your chances of getting a black by more than 10%. But with the new system, it drops by about 10%. These are cumulative and if you look over all the possibilities, you see that on average, the Red Army draw pile drops by an average of one mission per module.

I do not believe that many ASL players are under any illusion that the odds of drawing a black chit change with the addition of red chits under the Pleva system. That said, your data only addresses one of many variables.

How, for example, do you account for the overall benefit of removing the possibility of permanently losing an OBA battery? Is the net effect equivalent to or better than the potential loss of a single fire mission? Or put another way, how does one measure the threat of a fire mission?

Knowing that your opponent can no longer call in artillery provides one with greater freedom of action. It seems to me that the opposite would hold true if an opponent retained even the possibility of calling in a fire mission. Granted the degree to which this possibility effects enemy decision making varies according to the perceived level of risk at a given point in the game. Can this intangible effect be ignored? If not, how do you account for it in your analysis?

Similarly, what is the impact of the Pleva system on a scenario that is ten turns long? Presumably, a longer game would offset, at least to some degree, any decrease in the net number of fire missions by ensuring that the battery remained in play for the entire scenario. This not only ensures that OBA remains a threat after drawing two red chits, but also increases the number of times one can attempt to gain Battery Access. In other words, while the odds of drawing a black chit under the Pleva rule worsen over time, numerous chances (i.e., draws) remain for a black chit to be drawn.

Given the small Draw Piles of Chinese, Japanese, and Russian forces in ASL, what offers better value for these nationalities: a) having the possibility of more fire missions (in exchange for the risk of having none), or b) retaining the possibility of having a fire mission? Is there a tipping point such as scenario length, radio vs field phone, theatre, etc., that would favour one system over the other?

ASL clearly favours certain nationalities with larger Draw Piles. The authors of the ASLRB evidently deemed that other nationalities were less likely to succeed in calling in fire missions. Beyond that, I've no idea what the designers intended, and therefore am in no position to assess whether the Pleva Rule "distorts probabilities well beyond what the designers envisioned." It's entirely possible that on balance, the Pleva Rule is no better or worse than that provided for by Chapter C.

As for Steve's system "cheating nationalities with small Draw Piles," I'd like to see more evidence for this. Your graph is a good start. But it only looks at one impact of the Pleva Rule.

 

[bendizoid]

The main idea for the Pleva system is simple, stop the possibility of a early double red draw and never getting a Fire missions.

 

[BattleSchool]

The main idea for the Pleva system is simple, stop the possibility of a early double red draw and never getting a Fire missions.

Correct.

Moreover, while SSRs granting an auto black chit on the first draw guarantee at least one fire mission, they do not address player omniscience, which the Pleva Rule does.

 

[Steven Pleva]

Essentially, the house rule OBA system will result in one less fire mission per module than the new system on average for a standard Soviet Draw pile. View attachment 14673
The more cards in your draw pile, the less you lose.

This is because, as seen above, you are adding a red card every time you draw a red, reducing your percentage chance of getting a black card every time you draw red. With the old system, the first red you draw increases your chances of getting a black by more than 10%. But with the new system, it drops by about 10%. These are cumulative and if you look over all the possibilities, you see that on average, the Red Army draw pile drops by an average of one mission per module.

You are missing one very important aspect. Once you draw two red cards with the standard rules your chances plummet to zero forever. That is the great equalizer. For 6 draws the average number of fire missions with the standard rules (5B/2R) is 3.33. For my rules it is 3.18. However, the chances of getting zero missions is much smaller with my rules...
Steve

 

[jyoung]

Hatten in Flames (playing this now) uses yet another system for both nationalities - 3B/1R, any black drawn stays drawn, any red drawn gets put back as per the Pleva rules but no additional red (all extra chit draws replaced as usual). First time I've played with anything other than original OBA rules, certainly is nice to know you can't permanently "malf" your OBA with 2 red draws. Interesting consequence if you successfully get that last fire mission, you better make sure the observer can see a unit because you are guaranteed to draw red for your extra chit draw if not.

 

[BattleSchool]

Keith Dalton designed a scenario in Forgotten War that effectively uses the Pleva OBA Rule. See SSR3 in "210 This is Where We Stand."

 

[Actionjick]

You are missing one very important aspect. Once you draw two red cards with the standard rules your chances plummet to zero forever. That is the great equalizer. For 6 draws the average number of fire missions with the standard rules (5B/2R) is 3.33. For my rules it is 3.18. However, the chances of getting zero missions is much smaller with my rules...
Steve

Were you wearing the purple robes when you came up with this rule??

 

[BattleSchool]

Hatten in Flames (playing this now) uses yet another system for both nationalities - 3B/1R, any black drawn stays drawn, any red drawn gets put back as per the Pleva rules but no additional red (all extra chit draws replaced as usual). First time I've played with anything other than original OBA rules, certainly is nice to know you can't permanently "malf" your OBA with 2 red draws. Interesting consequence if you successfully get that last fire mission, you better make sure the observer can see a unit because you are guaranteed to draw red for your extra chit draw if not.

Hadn't noticed this before. Only played the scenarios so far. Thanks for drawing my attention to this Pleva-lite rule.

CG6. OBA: All HF OBA modules use a modified Draw Pile (C1.211) of three black and one red chit. Each module comes with one Pre-Registered hex (C1.73) [EXC: extra black chit is NA]. Drawn red chits are returned to the Draw Pile, but the drawing of two red chits does not cause loss of Battery Access for the duration of the scenario (C1.21).

 

[Actionjick]

The only thing I can think of is that the heavy surf may denote heavy swells out in the comparatively shallow water off shore where the ships lay for fire support. Pitch and roll may effect a cruisier or destroyers fire at the relatively short range that the ships are firing at (a few thousand yards at best).

Just skylarking but I'm not sure the analogue fire control 'computers' of the larger ships were accurate enough to correct for pinpoint accuracy required to put an FFE within 100m of the aiming while the ship is moving at low speed and being effected by the motion of the sea.

15,000 yards was considered close range and a hit was considered probable with the first salvo.

20,000 yards was considered medium range with a 15%-20% probability of a hit with the first salvo.

25,000 yards was considered long range with a 1%-2% probability of a a hit with the first salvo.

These were hits against a ship.

Haven't come up with any information yet on the normal ranges the gun line fired from.

I assume the bombarding ships would want to be out of the range of enemy shore artillery. 15,000 yards sounds out of range for most land based artillery.

Just information to mull over when thinking about the effects of heavy surf on NOBA.?

 

[Actionjick]

One of the things I really enjoy about the forum is checking out a thread I have no real interest in, coming across something in it that grabs me which leads to a whole new line of inquiry. Good stuff!!

This thread is a prime example. Looked at it. Saw NOBA, checked it out. The DRM for heavy surf raised my curiosity as a sailor. Now I'm interested in naval gunfire support in WWII. What more could you ask for?

Captain Bacchus says a box of wine. That's why he is a Captain and I was a snipe.

 

[jyoung]

Hadn't noticed this before. Only played the scenarios so far. Thanks for drawing my attention to this Pleva-lite rule, which is also similar to a NOBA Draw Pile.

You're welcome. BTW I have many of your dice, and yet somehow not enough . And I forgot to thank you for the freebie black panzerknackern dice on my most recent order.

 

[The Purist]

15,000 yards was considered close range and a hit was considered probable with the first salvo.

20,000 yards was considered medium range with a 15%-20% probability of a hit with the first salvo.

25,000 yards was considered long range with a 1%-2% probability of a a hit with the first salvo.

These were hits against a ship.

Haven't come up with any information yet on the normal ranges the gun line fired from.

I assume the bombarding ships would want to be out of the range of enemy shore artillery. 15,000 yards sounds out of range for most land based artillery.

Just information to mull over when thinking about the effects of heavy surf on NOBA.?

I would approach these number with some caution but certainly the closer the ships were to the shore the higher the probability of early hits being achieved. Nothing like the hundreds of rounds being expended in naval battles at 20,000+ yards against manoeuvering ships at 30 knots mind. Having well-trained shore parties also had a major impact on naval gun fire support.

Quantity has a quality of its own,.... as they say.

As an example I would point to the Salerno landings and the trouble the landings ran into as the Germans piled up six panzer (Herman Goering, 16th and 26th) and panzer grenadier (3rd, 15th and 29th) divisions in the first few days after the landings. American light cruisers such as Savannah, Boise and Philadelphia each mounted 15 x 6" guns, which meant a full broadside carried more weight than an entire battalion of 155mm medium artillery. Combined with other US and British 6" cruisers mounting 12 guns, the 8" cruisers and (later) the battleships Warspite and Valiant the naval guns broke up repeated attacks against the three (later four) British (46th, 56th) and American (36th reinforced by 45th) infantry divisions and their supporting tanks.

Destroyers came within 3000 yards of the shore line in order to send their salvos inland and the cruisers were operating between 5,000 and 10,000 yards of the shoreline but came closer inshore in order to lay bombardments down on German tank and artillery concentrations as much as 8000-9000 yards or more inland. Once ranged in it generally took only a few broadside salvos from the cruisers and battleships to destroy or drive off their targets.

The unit diary from the 16th Panzer divisions notes during the height of the German counterattacks that,

"Whenever German units attacked on the 14th September, such heavy fire from the sea and air struck them that they were only able to gain local successes...."

Between 13th and 14th Sept Philadelphia fired 921 rounds of 6" shells and was relieved by Boise. Boise then picked up the action firing more than 600 rounds at eighteen targets just that afternoon and evening. While that works out at an average of about 34 rounds per target, one target was a concentration of some 20 German tanks that was "obliterated" by 84 rounds from her guns.

The previous day Boise came close inshore and used used 36 rounds to silence a German heavy battery up in the mountains above the beachhead.

On the 16th of Sept, after further failed attacks, Vietinghoff (German 10th Army commnder) conceded,

"The attacks,... were unable to reach their objectives owing to fire from naval guns and low-flying aircraft, ... in order to evade the effective shelling from warships, I authorised the disengagement on the coastal front."

The allies did have troubles of course. Where shore parties were absent the German attacks caused serious damage and even had Mark Clark considering evacuating the American beachhead (we have a number of ASL scenarios covering the Salerno battles but w/o the naval guns).

Rinse and repeat at Anzio with lessons learned. At Anzio the naval guns were even more effective than at Salerno.

[I like to keep this information handy for when some folks talk about 'panzers on the beaches' in Normandy being decisive. Meh,... not so much.]