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Old 01-04-07, 09:24 AM   #31
fabel
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Quote:
Originally Posted by AS
Why is it so hard to understand the point of a "safety factor"???

A "safety factor" is used to provide SAFETY under normal conditions. In war, you don´t have "normal" conditions, so you´ll push it to the limit in an emergency - what else could you do?

If you take a ride in a rollercoaster, you´ll rely on a safety factor for weight. If it´s built for 20 people you can count on it that it had been tested with much more weight. The decrapancy between normal operation and tested (or calculated) operation is expressed in a safety factor.

If you want a NORMAL OPERATIONAL depth of, say, 100m, would you build a hull that will collapse at 110m? Probably not. But maybe you feel "safer" if you know all parts are able to endure the pressure you´ll find at 250m (which means they can take more than twice the pressure they will encounter under "normal" conditions).

The US Navy thought 1.5 was enough, which simply means that normal operational depth was closer to critical depth compared to German subs. Taking this into account, you´ll probably not try to dive two times deeper than operational depth in SH4, while you CAN do this in SH3. It is pretty obvious that Captains only dived deep to avoid depth charges or detection, it wasn´t fun. I talked to a U-Boat veteran and he told me that sometimes they dived so deep that the hull bended inside and "you could take a shower" in the engine rooms.

Cheers, AS
I agree
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Old 01-04-07, 03:13 PM   #32
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Fact is, because of the way the U-boats were designed and built, they could go much deeper than their U.S. counterparts, and far greater depths than the dockyard certificate stated as "safe".
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Old 01-04-07, 04:28 PM   #33
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That's the whole point of this discussion. The American boats could also go much deeper than the certifications said was "safe". How deep did either one actually go without being crushed? Was there really that much of a difference?
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Old 01-05-07, 10:44 PM   #34
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I don´t know how many times I´ve referred to the "safety factors" but here´s a wild guess: a WW2 US-sub will probably collapse between 1.6 and 1.7 times the operational depth. I´m curious though how SH4 is going to handle this.

Cheers, AS
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Old 01-06-07, 12:14 AM   #35
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Quote:
Originally Posted by AS
I don´t know how many times I´ve referred to the "safety factors" but here´s a wild guess: a WW2 US-sub will probably collapse between 1.6 and 1.7 times the operational depth. I´m curious though how SH4 is going to handle this.

Cheers, AS
Probably by crushing the boat...

WWII captains didn't know exactly how deep their boats would go, so that's why there were safe depth listings for them. If you stayed above that depth you knew you were always safe. You knew the boat was capable of diving deeper and if you had to you'd try it. How deep it could actually go? Well you wouldn't know that until you either went deep and came back up, or crushed like a beercan under a semi.

That's what we'll have to deal with as Captains as well, the uncertainty.

As for which exact numbers the Devs use, that's up to them. Unlike real skippers though we'll be able to figure it out eventually since even at DiD no one is going to hit you with a brick so you can never try it again...or tell anyone else.
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Old 01-06-07, 10:04 AM   #36
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...but WW2 captains knew the "secret" code for the estimated/calculated crash depth which was "3xR+60" (I guess "R" was about 50 or 60). Although considered a big secret, most U-Boat men knew about this later in war.

When early in war a Type IXb (U-123 I think it was) accidently dived to 200m Dönitz laughed at the captain and said: "Glad you proved how deep our U-Boats really can go, but was it really necessary to go for the world record?"

Cheers, AS
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Old 01-07-07, 07:41 PM   #37
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AS,

I don't know too many sub games that give you any more depth than the red line on the depth guage. Anything over that and you're toast. And soggy at that. For instance the late war US subs that could go to 400 ft safely, but in the games I've played, you go 1 foot deeper, and the hull crushes every time. I understand your point too. The boats were known to go well beyond the limit that the dock certificate stated, and there is yet to be a game, or simulator that reflects that very point unless some enterprising soul comes up with a mod for it.

It makes me wonder also how the game will deal with this aspect.

Very good point there AS.
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Old 01-07-07, 10:33 PM   #38
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Quote:
Originally Posted by bookworm_020
U.S.S Tang went to 600 feet during her first depth test. She went deeper when she went on patrol.

All the way to the bottom?
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Old 01-08-07, 11:57 AM   #39
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Quote:
Originally Posted by TwistedFemur
Quote:
Originally Posted by bookworm_020
U.S.S Tang went to 600 feet during her first depth test. She went deeper when she went on patrol.
All the way to the bottom?
Yes, which was about 180 feet in the Formosa Straits.
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Old 01-08-07, 06:11 PM   #40
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Talking about US dive depths we shoudn´t forget that real deep (I mean deeep) diving wasn´t that important for U.S subs, because the Japanese had mayn depth charge problems and in the beginning of the war they couldn´t actually re-set the depth parameters. From what I´ve read so far they didn´t even care much and their depth charges were often misplaced or went off in shallow depths like 35m.

Another point is that Japanese subs couldn´t dive very deep (about 75m), so they didn´t expect enemy subs to go deeper.

To cut it short: Dive depths were not as important for US skippers than it became in the Atlantic. Japanese ant-submarine technology and SKILL was rather limited---

Cheers, AS
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Old 01-10-07, 12:29 AM   #41
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The Japanese didn't use their subs as the US did either, and to make them playable in the game, would be a lesson in extreme tedium. Most missions cinsisted of resupplying the island outposts

That's not to say that they didn't sink any allied ships. The Yorktown, and Indianapolis are just a couple examples.
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Old 01-10-07, 01:30 AM   #42
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Quote:
Originally Posted by Hylander_1314
The Japanese didn't use their subs as the US did either, and to make them playable in the game, would be a lesson in extreme tedium. Most missions cinsisted of resupplying the island outposts

That's not to say that they didn't sink any allied ships. The Yorktown, and Indianapolis are just a couple examples.
And the Wasp and damaged the Saratoga and sink the liscome bay whatever.
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Old 01-10-07, 07:11 PM   #43
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The US Navy was very concerned with the development of ever deeper diving submarines. COMSUBPAC was able to gather substantial information from the many detailed submarine patrol reports. As the war progressed many new tactics were formulated from these reports in an effort to combine safer operations as well as increase thier killing effeciency. One of those tactics ofen used was to dive as deep as neceassry to find a boundary layer or thermal. Sometimes this was only a couple hundred feet. However, there were instances of having to go a deep as 400 feet.

The Balao, thick skin boat, was developed in large part to take full adavantage of this tactical evasion technic. In the deeper waters surrounding Japan this maneuver was widely used with much success.
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Old 01-10-07, 10:16 PM   #44
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Quote:
Originally Posted by cmdrk
Quote:
Originally Posted by TwistedFemur
Quote:
Originally Posted by bookworm_020
U.S.S Tang went to 600 feet during her first depth test. She went deeper when she went on patrol.
All the way to the bottom?
Yes, which was about 180 feet in the Formosa Straits.
Some of the crew were able to escape before being overcome by chlorine gas. These were people who weren't aft of the control room when the torpedo hit.
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Old 01-12-07, 10:39 AM   #45
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Quote:
Originally Posted by Hylander_1314
AS,

I don't know too many sub games that give you any more depth than the red line on the depth guage. Anything over that and you're toast. And soggy at that. For instance the late war US subs that could go to 400 ft safely, but in the games I've played, you go 1 foot deeper, and the hull crushes every time. I understand your point too. The boats were known to go well beyond the limit that the dock certificate stated, and there is yet to be a game, or simulator that reflects that very point unless some enterprising soul comes up with a mod for it.

It makes me wonder also how the game will deal with this aspect.

Very good point there AS.
Hylander,

I just finished a patrol on SH I with a Balao sub. Their test depth was 400 but I went right down to 500' with no issues (none either in SH II or III). Not even the "cracking" sound of the hull. I think with the Tang's ability to go to 600' - and that depth probably a rare occasion, US subs did go deep on occasion. Having bathythermograph equipment to test the thermal layer temps - from March '43 on - may have given reason for some deep dives to get away from sonar detection or the attempt to do so. Hopefully SH IV will continue to allow for such dives.

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