So how deep did the u.s subs go max?

[cmdrk]

Originally Posted by Subnuts

I wouldn't take an S-boat to 500 feet if I were you!

The safety factor probable applies to fully welded hulls. I think the P class was the first to have them.

[AS]

Sorry to say so, but you are WRONG if you compare the VIIb depth (90m) to that of a U.S. Sub. The reason is quite simple: The German Navy calculated a safety-factor of 2.5 for their "operational depth", while the U.S Navy calculated with approx. 1.5. This means:

Type VII U-Boat: 100m "safe" operational depth, multiplied by the factor 2.5 = 250m assumed maximum depth close to crash depth (today we know that the crash depth assumption were too pessimistic in those days, as you all know, U-Boats could go a bit deeper than 250m)

US-Sub: 90m (later 120m) operational depth, multiplied by 1.5 = 135 (respectively 180m) maximum depth near crash depth.

So, U.S. subs couldn´t go very deep, but they were not meant to, either, because in the Pacific both crash dive time (VIIc: 25sec., US Gato: 50sec.) and maximum depth didn´t play such an important role, whereas long range travelling, a huge torpedoe load-out and comparatively comfy crew accomodations were much more important for the Pacific theatre.

My two cents, AS

[Sailor Steve]

Originally Posted by AS

The German Navy calculated a safety-factor of 2.5 for their "operational depth", while the U.S Navy calculated with approx. 1.5.

Calculated crush depths are not necessarily the reality. I've heard of at least one Gato surviving 600 feet and more. Also, I've seen one source that shows the German depth as twice the test depth, not 2.5. This is not to say the German boats didn't go deeper, but US boats could go quite a bit deeper than they were rated.

[WilhelmSchulz.]

Originally Posted by Sailor Steve

Calculated crush depths are not necessarily the reality. I've heard of at least one Gato surviving 600 feet and more. Also, I've seen one source that shows the German depth as twice the test depth, not 2.5. This is not to say the German boats didn't go deeper, but US boats could go quite a bit deeper than they were rated.

Yes the Later boats(Balo and Trench) could easly go down to 600ft. But thats only as far as they went because that was the limit on the guage.

[MadMike]

From what I can find in historical narratives,the deepest depth that an S-boat went to was 267 feet (81.38m) by S-37.

Yours, Mike

[Cpt. Stewker]

EDIT: bad info. I was under the wrong assumption that the boat I mentioned was one of the US s-class submarines that America gave to the UK to use during WWII and not a newer UK built S-class boat. Very confusing.

To: Subnuts

Gotcha

[Subnuts]

Originally Posted by Cpt. Stewker

From this account, which you can find at http://www.marinefoundation.org/wreckshmsstubborn.htm, it seems that the deepest dive survived by an S-class sub was 166 meters.

That's a British S-boat. They're completely different designs.

http://en.wikipedia.org/wiki/British...ine_%281931%29

http://en.wikipedia.org/wiki/S-boat

[Sailor Steve]

Originally Posted by WilhelmSchulz.

Yes the Later boats(Balo and Trench) could easly go down to 600ft. But thats only as far as they went because that was the limit on the guage.

:rotfl:

Excellent point!

[CruiseTorpedo]

Originally Posted by cmdrk

The safety factor probable applies to fully welded hulls. I think the P class was the first to have them.

Ummm wait a minute.. They didnt weld the hulls all the way around on the early boats? How the heck were they water tight without welds going all around them? Did they use seals and crap instead of relying on tougher welds??

[Hylander_1314]

No boat is completely "sealed". That's why you have bildge pumps, and during Silent Running, they get shut off completely so as not to give away the position of the boat.

[geetrue]

Words of wisdom ... "Never trust a boat that has a bilge without water"

[AS]

Even if one US sub went to 600 feet, what´s the point? I just said that the safety factor was 2.5 in the German Navy, and about 1.5 in the US-Navy. Both the American and English Navy didn´t set their depth charges deeper than about 80 or so meters because THEY DID NOT EXPECT U-BOATS TO BE ABLE TO GO DEEPER THAN THAT in the beginning of the war. Their assumption was based on their own submarine constructions. In other words: it was not known (or believed) that any sub could go much deeper than approximately 100m (~300ft). This implies that American subs were not supposed or meant to be capable of deep diving.

Cheers, AS

[cmdrk]

Originally Posted by CruiseTorpedo

Ummm wait a minute.. They didnt weld the hulls all the way around on the early boats? How the heck were they water tight without welds going all around them? Did they use seals and crap instead of relying on tougher welds??

From here:
http://www.chinfo.navy.mil/navpalib/.../subsaga6.html

Here's a snippet:
Between 1932 and 1941, Portsmouth built an additional 22 submarines in the 1500-ton category. It was during this period that the first all-welded submarine, USS Pike (SS-173), was completed. The welded hull allowed Pike to submerge to much greater depths than her predecessors and at the same time provided greater protection against depth-charge attacks.

[Oesten]

For me, I wouldn't call '2.5 times rated operational depth' a safety factor! Rather an 'unsafe' factor.....

I wouldn't want to go deeper than 180 meters (600 ft) in a Type VIIB unless in a dire emergency. That's twice the rated depth of 90 metres. Going deeper than that, and you're risking your lives on whether your particular boat is as well constructed as you hope it is! A Type VIIC I'd take to 200 meters, but no lower unless I had no choice.

For US subs, I wouldn't want to go deeper than 1.5 times the rated depth if I could help it. That's:

Barracuda Class : ~300 feet = 91 meters
P-Class, Salmon, Sargo, Tambor, Gar Classes: ~375 feet = 114 meters
Gato Class: ~450 feet = 136 meters
Argonaut, Narwhal Classes: ~465 feet = 151 meters
Balao, Tench Classes: ~600 feet = 182 meters

The old S-class I wouldn't dare take lower than 200 feet even under the heaviest depth charging, because they are so old I wouldn't trust them any lower! The older a sub is, the less likely it is to withstand pressures significantly greater than test depth.

The S-37's captain must have been truly desperate to take her to 267 feet!

[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