The potential danger of highly-volatile aviation gasoline

[admiralhood]

Hi all,

In this post I would like to discuss the  combustible nature of aircraft carrier.

Hundreds of thousands of gallons of aviation gasoline are stored in a carrier. Unlike the fuel used by ships, it is of high volatility and highly inflammable, if the vapor of such substance accumulate within a ship, could cause severe damage to the ship several hours after it has been hit, which is something could not happen on a battleship or a cruiser. In WW2, both US Lexington and Japanese Taiho were sunk due to the explosion of accumulated aviation gasoline several hours after the hit. 

Is there any plan in RTW2 to reflect the combustible nature of carriers?

[oldpop2000]

You might find this interesting about the Lexington.

RECOMMENDATIONS
As a result of the study of this case the following recommendations were made for immediate application to Saratoga, and, in so far as applicable, to all other aircraft carriers: -

Saratoga to keep layer of tanks inboard of gasoline tanks void and filled continuously with inert gas mixture. (NOTE: The first part of this recommendation, to keep these spaces void, had previously been made to both Saratoga and Lexington) This step should operate to reduce shock damage to the holding bulkhead in case of a torpedo hit in this area.

Saratoga to segregate port and starboard gasoline systems in order to avoid the possibility of pressure being put on a damaged system from an undamaged system.
All Carriers:-

In event of suspicion of gasoline vapors following attack operate exhaust ventilation in affected compartments as considered practicable. Early operation of these systems should prevent dangerous concentrations of gasoline vapor.

Shut down all electrical equipment subject to sparking throughout entire affected area, except where it is considered safe and desirable to run exhaust ventilation blowers.

Inspect all vent ducts from spaces involved to guarantee tightness. This should be done periodically before an attack, and again after the attack.
Steps were also taken to insure that the following equipment would be on board each carrier at the earliest possible date:
15 asbestos suits

60 Type A rescue breathing apparatus

1 Fog nozzle for each fire plug

[admiralhood]

Dec 8, 2018 22:42:59 GMT -6 oldpop2000 said:

You might find this interesting about the Lexington.

RECOMMENDATIONS
As a result of the study of this case the following recommendations were made for immediate application to Saratoga, and, in so far as applicable, to all other aircraft carriers: -

Saratoga to keep layer of tanks inboard of gasoline tanks void and filled continuously with inert gas mixture. (NOTE: The first part of this recommendation, to keep these spaces void, had previously been made to both Saratoga and Lexington) This step should operate to reduce shock damage to the holding bulkhead in case of a torpedo hit in this area.

Saratoga to segregate port and starboard gasoline systems in order to avoid the possibility of pressure being put on a damaged system from an undamaged system.
All Carriers:-

In event of suspicion of gasoline vapors following attack operate exhaust ventilation in affected compartments as considered practicable. Early operation of these systems should prevent dangerous concentrations of gasoline vapor.

Shut down all electrical equipment subject to sparking throughout entire affected area, except where it is considered safe and desirable to run exhaust ventilation blowers.

Inspect all vent ducts from spaces involved to guarantee tightness. This should be done periodically before an attack, and again after the attack.
Steps were also taken to insure that the following equipment would be on board each carrier at the earliest possible date:
15 asbestos suits

60 Type A rescue breathing apparatus

1 Fog nozzle for each fire plug

Thanks for your footnote oldpop. 

Filling aviation fuel tank with inert gas should be included in the damage control branch of the tech tree. If such technology has not been researched yet, than there should always be a possibility of losing your precious carrier to such secondary disaster.

Btw, to your knowledge, is USS Princeton (CVL-23) sunk due to a similar reason?

[oldpop2000]

Dec 8, 2018 23:26:54 GMT -6 admiralhood said:

Dec 8, 2018 22:42:59 GMT -6 oldpop2000 said:

You might find this interesting about the Lexington.

Thanks for your footnote oldpop. 

Filling aviation fuel tank with inert gas should be included in the damage control branch of the tech tree. If such technology has not been researched yet, than there should always be a possibility of losing your precious carrier to such secondary disaster.

Btw, to your knowledge, is USS Princeton (CVL-23) sunk due to a similar reason?

Thanks, I am glad you liked it.  As to the Princeton, the bomb that hit her forward of the aft elevator penetrated and knocked out the after fire fighting system. The bomb did cause a fire in the burning gasoline which caused further explosions. The second explosion was probably caused by one or more bombs in the magazine. I don't think the crew had time to drain the fuel lines in the hangar and fill them with foam. The Judy was lost in a rain cloud and suddenly reappeared on the port bow already heading on her attack. The 550 lbs. bomb ignited the torpedoes in the open bomb bays of the Avengers, these cooked off.

A simple comment: All the best damage control features and plans are of no value unless you have time to implement them. I think, but haven't confirmed, that this was the problem with the USS Princeton. The sudden appearance of the Judy, never gave the crew time to perform the necessary damage control procedures and the result was the loss of the ship.

[admiralhood]

Here is my idea how could we simulate what has happened to USS Lexington in the Battle of Coral Sea and to IJN Taiho in the Battle of the Philippine Sea:


1. If a carrier was hit by a torpedo or an armor-piercing bomb, the game is going to decide whether the aviation gasoline tank has been damaged.

2. If the the aviation gasoline tank has been breached, and countermeasures has not been researched, a gas explosion probability factor starts to grow from zero. Each minute, such factor should grow 0.1% for a carrier with an enclosed-hangar carrier or 0.002% for a carrier with open-hangar carrier because for the later it is easier to dissipate the aviation fuel vapor(which would make the player to think which one is a better choice for his carrier fleet ). And then each turn the system would "roll the dice" according to the current gas explosion probability factor(e.g. after 60 minutes the probability increased from 0 to 6% because of the accumulation of the aviation fuel vapor, and then each turn the carrier should stand a 1 out of 16 Russian Roulette).

3. If the aviation fuel vapor has not been sufficiently vented out and the player still choose to conduct aerial operations(e.g. launching or receiving aircraft), the carrier should stand a 60% chance of internal blow-up(which is not necessary to doom the ship always though, USS Franklin survived something even worse) each turn during such process(The Russian Roulette becomes a 3 out of 5!). Both USS Lexington and IJN Taiho exploded when the crew of the ship believed that the had recovered from the torpedo hit and therefore started aerial operations again. The main objective for this feature is to discourage a admiral to continue to use his carrier when it was already damaged.

4. If the breach of the aviation fuel tank is sealed and proper and safe ventilation(which is not always the case) has started, the factor mentioned in 2 should start to decrease, for a similar reason, for a carrier with enclosed hangar, such factor should decrease with a slower rate. 

4. Filling aviation fuel tank with inert gas should be included in the tech tree of "carrier damage control". However, such countermeasure should only decrease the probability of such internal gas explosion(e.g. from 0.1% growth per minute to 0.01% growth per minute) instead of eliminating the probability completely. A good example would be CVL-23 Princeton,  in 1944 the damage control ability of the US navy is already way much better than 1942 and such incident still happened. Therefore I believe it is fair to say that such incident could not be avoided completely.  

williammiller jwsmith26

May I ask you if there is any plan to emphasis this vulnerable side of a carrier in RTW2?  This could be something unique for the damaging control of a carrier which the battleships would never encounter. 

[rimbecano]

I'm not sure an open hangar should reduce things any. My impression is that the vapor accumulation aboard Lexington was well below the hangar deck.

[oldpop2000]

Dec 10, 2018 10:27:45 GMT -6 rimbecano said:

I'm not sure an open hangar should reduce things any. My impression is that the vapor accumulation aboard Lexington was well below the hangar deck.

I am glad someone else figured that out. Enclosed hangers prevent another ship from spraying water into the hangar, that is one advantage of the open hangar. You can also warm up radial engines in an open hangar, you can't in an enclosed hangar. This helps in maintenance because if an aircraft is having an engine problem, you work on it and test it in the hangar. Generally up front, there is an area where removed engines can be tested. It does help a little be able to get the gasoline vapors out of the hangar bay, but down below the hangar only an exhaust system will work. The Lexington was filling with gasoline vapors and a motor ignited those vapors. The AAR recommended that in those cases, all electrical equipment must be shut down and the ship opened up.

[director]

I'd like to see a gradual improvement in damage control implemented by wartime experience and lost again in peacetime.

After the blazing pyres of allied cruisers at Savo island, the US Navy got serious about removing linoleum, flammable paint, wood, fabric and the like, and a number of ships were saved from 42-45 despite massive damage.

I'd say the Royal Navy went through the same process, perhaps coming to it sooner, while the Axis navies don't seem to have been very good at damage control.

[garrisonchisholm]

Dec 9, 2018 14:46:41 GMT -6 admiralhood said:

Here is my idea how could we simulate what has happened to USS Lexington in the Battle of Coral Sea and to IJN Taiho in the Battle of the Philippine Sea:


1. If a carrier was hit by a torpedo or an armor-piercing bomb, the game is going to decide whether the aviation gasoline tank has been damaged.

2. If the the aviation gasoline tank has been breached, and countermeasures has not been researched, a gas explosion probability factor starts to grow from zero. Each minute, such factor should grow 0.1% for a carrier with an enclosed-hangar carrier or 0.002% for a carrier with open-hangar carrier because for the later it is easier to dissipate the aviation fuel vapor(which would make the player to think which one is a better choice for his carrier fleet ). And then each turn the system would "roll the dice" according to the current gas explosion probability factor(e.g. after 60 minutes the probability increased from 0 to 6% because of the accumulation of the aviation fuel vapor, and then each turn the carrier should stand a 1 out of 16 Russian Roulette).

3. If the aviation fuel vapor has not been sufficiently vented out and the player still choose to conduct aerial operations(e.g. launching or receiving aircraft), the carrier should stand a 60% chance of internal blow-up(which is not necessary to doom the ship always though, USS Franklin survived something even worse) each turn during such process(The Russian Roulette becomes a 3 out of 5!). Both USS Lexington and IJN Taiho exploded when the crew of the ship believed that the had recovered from the torpedo hit and therefore started aerial operations again. The main objective for this feature is to discourage a admiral to continue to use his carrier when it was already damaged.

4. If the breach of the aviation fuel tank is sealed and proper and safe ventilation(which is not always the case) has started, the factor mentioned in 2 should start to decrease, for a similar reason, for a carrier with enclosed hangar, such factor should decrease with a slower rate. 

4. Filling aviation fuel tank with inert gas should be included in the tech tree of "carrier damage control". However, such countermeasure should only decrease the probability of such internal gas explosion(e.g. from 0.1% growth per minute to 0.01% growth per minute) instead of eliminating the probability completely. A good example would be CVL-23 Princeton,  in 1944 the damage control ability of the US navy is already way much better than 1942 and such incident still happened. Therefore I believe it is fair to say that such incident could not be avoided completely.  

williammiller jwsmith26

May I ask you if there is any plan to emphasis this vulnerable side of a carrier in RTW2?  This could be something unique for the damaging control of a carrier which the battleships would never encounter. 

Not to say that William or John may not reply, but we have a 40-page internal thread on carrier operations, and the multitudinous perils of the different types of fueling & arming operations that embattled navies faced have been long discussed in depth.  We are currently waiting to see what Fredrik chose to include in the first models of carrier vs carrier action.  Which, I would wager (but not guarantee) that the first air-only AAR would be available here within the next 3 or 4 weeks.

[dorn]

I would just note that it is complex issue. Japanese were least prepared, RN most prepared. RN was worried about fuel explosions and make a lot of efforts to protect ships from explosions. But all have the costs. RN system was safer than USN But it took moore displacement.

At the end your countermeasures depend on:
1. Your approach (how important you consider it, how much resources you put into research - USN&RN vs. IJN)
2. Design decision (RN vs. USN)
3. TRAINING (RN & USN vs. IJN)

[williammiller]

Dec 9, 2018 14:46:41 GMT -6 admiralhood said:

Here is my idea how could we simulate what has happened to USS Lexington in the Battle of Coral Sea and to IJN Taiho in the Battle of the Philippine Sea:


1. If a carrier was hit by a torpedo or an armor-piercing bomb, the game is going to decide whether the aviation gasoline tank has been damaged.

2. If the the aviation gasoline tank has been breached, and countermeasures has not been researched, a gas explosion probability factor starts to grow from zero. Each minute, such factor should grow 0.1% for a carrier with an enclosed-hangar carrier or 0.002% for a carrier with open-hangar carrier because for the later it is easier to dissipate the aviation fuel vapor(which would make the player to think which one is a better choice for his carrier fleet ). And then each turn the system would "roll the dice" according to the current gas explosion probability factor(e.g. after 60 minutes the probability increased from 0 to 6% because of the accumulation of the aviation fuel vapor, and then each turn the carrier should stand a 1 out of 16 Russian Roulette).

3. If the aviation fuel vapor has not been sufficiently vented out and the player still choose to conduct aerial operations(e.g. launching or receiving aircraft), the carrier should stand a 60% chance of internal blow-up(which is not necessary to doom the ship always though, USS Franklin survived something even worse) each turn during such process(The Russian Roulette becomes a 3 out of 5!). Both USS Lexington and IJN Taiho exploded when the crew of the ship believed that the had recovered from the torpedo hit and therefore started aerial operations again. The main objective for this feature is to discourage a admiral to continue to use his carrier when it was already damaged.

4. If the breach of the aviation fuel tank is sealed and proper and safe ventilation(which is not always the case) has started, the factor mentioned in 2 should start to decrease, for a similar reason, for a carrier with enclosed hangar, such factor should decrease with a slower rate. 

4. Filling aviation fuel tank with inert gas should be included in the tech tree of "carrier damage control". However, such countermeasure should only decrease the probability of such internal gas explosion(e.g. from 0.1% growth per minute to 0.01% growth per minute) instead of eliminating the probability completely. A good example would be CVL-23 Princeton,  in 1944 the damage control ability of the US navy is already way much better than 1942 and such incident still happened. Therefore I believe it is fair to say that such incident could not be avoided completely.  

williammiller jwsmith26

May I ask you if there is any plan to emphasis this vulnerable side of a carrier in RTW2?  This could be something unique for the damaging control of a carrier which the battleships would never encounter. 

Right now we actually happen to be looking at carrier damage from play-test reports of hits/damage on CVs, so we are keeping such vulnerabilities in mind...that also includes considering the effects of having a loaded strike group on your deck when the dive bombers start raining down iron upon you

[triggerhappypilot]

Dec 23, 2018 9:58:57 GMT -6 williammiller said:

Right now we actually happen to be looking at carrier damage from play-test reports of hits/damage on CVs, so we are keeping such vulnerabilities in mind...that also includes considering the effects of having a loaded strike group on your deck when the dive bombers start raining down iron upon you

This brings up an interesting point, in that the rearmarment/refueling of strike aircraft was handled differently in different navies. In the IJN, for example, doctrine seemed to demand that planes be moved back into the hangar for refueling and rearmarment, whereas in the US carriers refuel and rearmarment on deck seems to have been broadly used. This might be an important doctrinal choice in game, especially with regards to armored-deck carriers.

For example, an armored deck carrier may, by doctrine, be required to recover all aircraft into the hangar deck to begin refuel and rearmament. This naturally slows down carrier operations, but as an advantage the carrier is never really that vulnerable, since all explosives are contained within the armored box of the deck and thus a shell, bomb, or torpedo must first penetrate the armor to start a catastrophic fire. On the other hand, if refuel/rearmament is allowed on deck, flight operations can naturally proceed faster but there is a significant risk of massive damage if the carrier is hit during this time. Since this reflects a doctrine it might be included with other doctrines such as torpedo training etc. and be able to be changed as the situations require.

Of course this may just be a bit too complicated for a game of this scope, but I think it might go a long way towards making armored deck carriers more viable/differentiated in combat as compared to unarmored carriers, which were historically stronger for their larger air groups.

[oldpop2000]

The 3 inch armored deck of the British carriers could only resist a 500 lbs. semi-armor piercing bomb dropped from below 7000 ft or a 250 lbs. SAP bomb from below 11,500 Ft. It could only resist a 1000 lbs. bomb from below 4500 FT. This system is better than no armored deck at all, but not fool-proof by any means. The discussion about the value of armored flight decks has been going on for over 70 years. One aspect is that you have to lower the hangar deck roof to maintain the center of gravity of the ship for the purposes of stability. The lower roof eliminates any stowage of extra aircraft parts like wings etc. or fully equipped aircraft that only have to be assembled.

[JagdFlanker]

as it so happens Drachinifel just released a vid on armored vs unarmored flight decks
youtu.be/_dHdGHP8hCg

it's this channel's fault i broke down and started a new RtW campaign on the weekend, dangit! so much for waiting for RtW2...

[dorn]

Jan 2, 2019 7:31:03 GMT -6 JagdFlanker said:

as it so happens Drachinifel just released a vid on armored vs unarmored flight decks
youtu.be/_dHdGHP8hCg

it's this channel's fault i broke down and started a new RtW campaign on the weekend, dangit! so much for waiting for RtW2...

Thanks for sharing. It is really jewell on that topic.