Realism- and gameplay-related hardcode fixes for SH3.EXE

[SquareSteelBar]

Originally Posted by h.sie

...
-"High pressure in boat,Sir"
-"Very high pressure in boat,Sir"
-"Very very high pressure in boat, we have to surface!"
-"Aaaaargh!" and so on...

The problem isn't the slow increase of pressure but the sudden decrease of pressure when the hatch is opened -> diver's paralysis [blood starts boiling]...

[h.sie]

@SSB:

I think Stieblers main interest is to limit the diving time per diving session and force the player to surface after some hours, because the usage of O2 supply causes an increase of the pressure in the boat. Currently, a type VII sub can stay submerged for max. 72 hours without surfacing.

@Stiebler:

Regarding LGN1's research, a type VII can dive up to 72 hours (he can surely give you the literature link). This is in total contrast to your opinion.

I think we need (historical) facts.

But let's assume, that LGN1's literature is wrong and the pressure in the boat limits diving-time. What shall happen if the player ignores your suggested warning "We have to surface"?

[Wolfstriked]

Is it possible that the compressed oxygen canisters were not high enough pressure wise to force the air pressure to dangerous levels?

[Anvart]

May be i'm wrong ... but the excess of air in the submarine can be compressed and thrown through torpedo tubes (or through special device).
or i badly understand your fu***ing english.

[LGN1]

The crucial thing you are missing is that the CO2 is chemically bound, i.e., it's removed. Without adding O2 you would get a lower pressure.

Cheers, LGN1

[h.sie]

@Stiebler (and NGT):

You both seem to desire a huge O2 supply that only seldom causes any problems / bottleneck.

a) So let's neglect these problems caused by O2-supply and set your desired O2-Supply to infinity in good approximation.

b) Now let's restrict the maximum diving-time per diving-session (caused by air pressure - or anything else) to, say, 36 to 72 hours.

(.....)

-> That's exactly the behaviour of the unpatched sh3.exe !!!

It seems that this behaviour fits your requirements much better than the current O2-Supply-Mod.

In the earlier patch versions before the O2-Supply-Mod, I only added some dependency of the diving-time on silent-running & repairs, but to be honest, in the meantime I think, that the influence of these factors on gameplay isn't significant enough to legitimate the programming effort. I wouldn't do it again.

So what is the problem with simply disabling the O2-Mod and use stock sh3 diving times (I'll help you to adjust them to fit your taste!).

In the moment, because we have only sparse historical facts, I don't plan to program anything new - based on assumptions......maybe later with more known facts!

@Stiebler: Since you anyway make an Addon (for Surrender-Mod), why not also put the old CO2-Mod from V15E in it?

[Stiebler]

@H.sie,

I sent you a PM, before I saw your last post.

I agree with the substance of what you said above.

However, a replacement V15E CO2 mod (using your code!) would better overwrite the existing V15G1 oxygen supply, than be a new addition.

Stiebler.

[h.sie]

@Stiebler: I have no problem if you overwrite the O2-Mod in your Addon, since it's your Addon that should fit your (and not my) requirements.

[Wolfstriked]

72 hours of stored O2 seems like a huge amount.Great to have for long patrols when your forced down for hours at a time.But,and I mentioned this before,It takes 2 minutes to refill the renewable air supply.Why even use the O2 supply when traveling submerged thru canals etc when a quick observation,surface for 2 minutes and back down to safety would save the precious O2.

I know that you guys have limited time and I think the O2 mod is really suffice as is.Its much more realistic than the original one

[Stiebler]

Regarding LGN1's research, a type VII can dive up to 72 hours (he can surely give you the literature link). This is in total contrast to your opinion.

I agree, there is no argument. However, the crew would be crippled by exhaustion.

My problem is that any U-boat should be able to cruise for 20 hours submerged, without silent-running, and without crippling the crew. A leisure cruise, almost.

Furthermore, the U-boat should be able to do it at any time, provided that it has renewed its air on the surface first. V15G1 does not permit this for more than 3 days, after which the compressed air supply is used-up.

Stiebler.

[Silent Ace]

Originally Posted by h.sie

@SilentAce: Already on the todo-list.

[LGN1]

The air volume of the VIIC is approx. 400m^3 according to the original handbook from 1940.

Let's take an oxygen percent of 21% in air. At 17.5% oxygen has to be added according to the original handbook,i.e., 400 000l*0.035=14000l oxygen is available without any supply.

With a crew of 37 men and a submerged endurance of 20h this would mean that one man can consume on average 18.9l/hour oxygen. The original manual assumes 30l/hour for each man.

If you look around in the internet you can find that 18.9l/h oxygen consumption is really low. According to the quoted numbers, I doubt that staying submerged for 20h without adding oxygen would be a 'pleasure'.

Cheers, LGN1

[h.sie]

Only a thought:

In addition to the discussion about historical accuracy, one should also consider the different timescales of sh3 and "reality":

According to some books I read, hunting an UBoot sometimes took more than one day (if I remember correctly). In Sh3, a hunt won't take a day (this is an assumption - never tested). So in my opinion a good balance between Player UBoat and enemy is more important than historical accuracy. That means (in my opinion): diving times don't have to be as long as in reality.

[Silent Ace]

type 7c with capacity of 400 000 liters of air, of which at a concentration of 21% O2 contains 84 000 liters of oxygen.
average person breathes in 12-20 times per minute.
With each respiration inhaled 500 ml of air.
12 * 500 ml = 6 000 ml = 6 liters of air.
at a concentration of 21% 02
6 liters of air/ 21 %O2= 1.26 liters of O2 per minute per sailor.
1,26 liters O2 * 60 minutes = 75.6 liters of oxygen per hour or 1814,4 liters of O2 per day per man.
1814 liters of O2 * 37 man = 67,132 liters of oxygen per day for the crew of the submarine type 7c.
If the total amount of oxygen of 84 000 liters divided by the total daily consumption of the crew gives a score of 1.25 days or 30 hours.
after these 30 hours if no additional reserves of oxygen in the submarine are all dead.
Drager apparatus using a personal set of escape can be obtained for another 45 minutes and that's it.

[LGN1]

@Silent Ace:

I think there are two mistakes in your calculation:

1. When you are breathing your body does not consume all the oxygen in the air. Only a part is used (that's why you can support breathing in a first aid situation).

2. The complete oxygen in a sub cannot be used. The concentration must not drop below 17.x%.

Cheers, LGN1