Dive depth

[Dignan]

Currently in a Gato class sub. I did a test dive and brought her to as far as the depth meter would go, 450. Is this normal? Should I have seen some seems bursting or damaged the hull? The boat was definitely groaning something fierce as the pressure pushed on the hull but I experienced no damage or warning. I'm running TMO1.4 and NSM4.

[Ducimus]

You can go deeper then 450 feet in a gato, how much more is ummm, well, you'll have to figure that out the hard way. It's Deeper then you think, but not as deep as a thick skinned boat ;)

BTW, make sure your in the conning tower when looking for flickering lights and other signs of stress - they show in the CT first. WHen they show in the control room, its a little too late to do anything about it.

[V.C. Sniper]

700 feet or a little deeper would be the limit of a Gato class.

[Ducimus]

Maybe a balao, but certainly not a gato.

[-Pv-]

There is no HARD and fast limit to depth. Every individual boats has a slightly randomized variation on the limit. Some less, some more. "You pays your moneys and takes your chances."
-Pv-

[Dignan]

You can go deeper then 450 feet in a gato, how much more is ummm, well, you'll have to figure that out the hard way. It's Deeper then you think, but not as deep as a thick skinned boat ;)

BTW, make sure your in the conning tower when looking for flickering lights and other signs of stress - they show in the CT first. WHen they show in the control room, its a little too late to do anything about it.

Thanks for the tip.

[M. Sarsfield]

WHen they show in the control room, its a little too late to do anything about it.

I slowly took an S-18 down to 300 feet as a dive test. I was in the control room monitoring the progress and at 296 ft. the lights started to flicker. I immediately ordered emergency surface. The boat sustained 3% hull damage. It sounds like if I was in the CT, that I probably would not have had any damage, since I would have risen the boat sooner.

[Ducimus]

All bets are off with the S class. It just behaves differently in every way concieveable.

[Zayphod]

You can go deeper then 450 feet in a gato, how much more is ummm, well, you'll have to figure that out the hard way. It's Deeper then you think, but not as deep as a thick skinned boat ;)

After a very deep dive to evade a destroyer......

"Remind me to write a letter to the Electric Boat Company when we make it back to port."

"Yes sir. What will it say?"

"Thank you."

I apologize for not being able to remember the movie that came from.....I'm old. I forget stuff.

[Platapus]

After a very deep dive to evade a destroyer......

"Remind me to write a letter to the Electric Boat Company when we make it back to port."

"Yes sir. What will it say?"

"Thank you."

I apologize for not being able to remember the movie that came from.....I'm old. I forget stuff.

That would have been the movie Operation Pacific (1951). :smug:

Ward Bond as Cmdr. John T. 'Pop' Perry talking to a very young Martin Milner (Adam-12) as Ens. Caldwell

[The Fishlord]

According to my spinning depth gauges, I took a Type 18 from the UBM add on to 1148 feet. The best way to do it is just order all stop on the engines, then hit the D button onces, and you should start diving. You won't stop till you die or you order a surface. I was in the red at 590 feet and the hull was creaking badly but it wasn't till, like I said, over a thousand that I started getting damage. It was catastrophic...Not something like three hull damage.

The hull was damaged to about 98%, all bulkheads were destroyed, propellers destroyed, all engines destroyed, BATTERIES destroyed, and my last hope of surfacing, Walther destroyed. Naturally the moment the lights flickered I ordered flank ahead with the Walther and emergency surface, but to no avail...the chains of reports started rolling in.

[Fincuan]

Naturally the moment the lights flickered I ordered flank ahead with the Walther and emergency surface, but to no avail...the chains of reports started rolling in.

I'm not sure about the XVIII, but in the IXD2 the lights start to flicker well after your hull starts taking damage. In US boats the lights are a good indicator, but in german boats I'd keep my eyes on the hull damage indicator.

[-Pv-]

Rarely (if ever) have I had to go to or stay at max depth to evade an attack. Remember, historically, the IJN didn't know how deep fleet subs could go and tended to set them too shallow. All bets are off though if you are giving the enemy pleny of information to accurately track you. The best technique is to quickly dive to a moderately evasive depth (I start with 155) and gradually dive deeper as your percieved risk increases. This way the enemy is always guessing at your true depth. You are never at one depth long enough for a bracket targeting that depth to work more than once.
-Pv-

[Zayphod]

Rarely (if ever) have I had to go to or stay at max depth to evade an attack. Remember, historically, the IJN didn't know how deep fleet subs could go and tended to set them too shallow. All bets are off though if you are giving the enemy pleny of information to accurately track you. The best technique is to quickly dive to a moderately evasive depth (I start with 155) and gradually dive deeper as your percieved risk increases. This way the enemy is always guessing at your true depth. You are never at one depth long enough for a bracket targeting that depth to work more than once.
-Pv-

As an experiment - has anyone tried several "test to destruction" dives? Just making 5 or 6 dives in the same class of sub until it crushes - would they be about the same for each dive, or vary a bit after a certain depth?

Of course, one would not do this with a real, live crew, for all the obvious reasons, but it would be interesting to see if the physics were pretty much the same for 5 dives in a Gato, etc.

[-Pv-]

Not sure the value of that partiticular style of testing. The manual and readmes state damage is progressive. As you take a little damage, the ability to resist more damage at the same depth decreases. The longer you continue the risk, the faster more damage occures. Amazingly rapidly, you cross the threashold of the domino effect.

It has been well proven by the experience of many that once the sub starts showing signs of damage, not only can you not continue to stay at that depth, but you may not even be able to get close to it again. Take enough damage and you cannot even get to P depth anymore. Your next dive to 100 ft might make it. You might start breaking up at 80ft. Maybe 10. Skill of the crew, Your ability to click and prioritise quickly, repairs made, how quickly you change depth, whether you are under attack (the near misses further weakening weak points) complicate the picture.

Moral: Avoid all damage to the best of your ability and once damaged, reduce risk or return to port. There are a couple of external programs you can install which will analyse your saved games and make recommendations about performance and risk. I've found my own experience and careful test dives gives me a better idea of my true limits (just like the real world.)

One indication of the quality of the simulation is when no two players have identical experiences, feeling like the presentation is uniquely your own. SH4 does this really really well.
-Pv-

[V.C. Sniper]

Rarely (if ever) have I had to go to or stay at max depth to evade an attack. Remember, historically, the IJN didn't know how deep fleet subs could go and tended to set them too shallow. All bets are off though if you are giving the enemy pleny of information to accurately track you. The best technique is to quickly dive to a moderately evasive depth (I start with 155) and gradually dive deeper as your percieved risk increases. This way the enemy is always guessing at your true depth. You are never at one depth long enough for a bracket targeting that depth to work more than once.
-Pv-

As an experiment - has anyone tried several "test to destruction" dives? Just making 5 or 6 dives in the same class of sub until it crushes - would they be about the same for each dive, or vary a bit after a certain depth?

Of course, one would not do this with a real, live crew, for all the obvious reasons, but it would be interesting to see if the physics were pretty much the same for 5 dives in a Gato, etc.I did the "test to destruction" dive for the Porpoise class 7-9 times in Silent Hunter 4: Wolves of the Pacific. The results every time (with 100% undamaged pressure hull) are:

Safe depth = 350 feet (351 feet is also safe)

Crush depth = below 350 feet (Once you get below 350 feet to 352 or more, the sub will begin to take damage until the pressure hull collapse and you die)

I find the crush depths in Silent Hunter 4: Wolves of the Pacific to be too shallow :nope:. Look at the USS Salmon(SS-182)!! She was forced to dive to nearly 500 feet to evade after taking some damage from the Japs and she made it out alive!

[stillalearnin]

I wonder if they have a test depth, like in modern boats or was it just the big red dont do that line, better known as crush depth. You can go past test depth by a decent margin in modern boats. Been there and done that.

It would seem like every boat would be a little different, the more you make, the more you tinker with the design. So it would be something that gets turned over to each new CO, kinda like this is her tendencies. Bubbleheads know their boat inside and out, have to for quals, and I would think that would be a keen piece of information.

[Zayphod]

Not sure the value of that partiticular style of testing. The manual and readmes state damage is progressive. As you take a little damage, the ability to resist more damage at the same depth decreases. The longer you continue the risk, the faster more damage occures. Amazingly rapidly, you cross the threashold of the domino effect.

It has been well proven by the experience of many that once the sub starts showing signs of damage, not only can you not continue to stay at that depth, but you may not even be able to get close to it again. Take enough damage and you cannot even get to P depth anymore. Your next dive to 100 ft might make it. You might start breaking up at 80ft. Maybe 10. Skill of the crew, Your ability to click and prioritise quickly, repairs made, how quickly you change depth, whether you are under attack (the near misses further weakening weak points) complicate the picture.

Moral: Avoid all damage to the best of your ability and once damaged, reduce risk or return to port. There are a couple of external programs you can install which will analyse your saved games and make recommendations about performance and risk. I've found my own experience and careful test dives gives me a better idea of my true limits (just like the real world.)

One indication of the quality of the simulation is when no two players have identical experiences, feeling like the presentation is uniquely your own. SH4 does this really really well.
-Pv-

I see. So it's a cascade type of thing. Once things pop, other things start going as well.

I was wondering about the depth, though, and I believe your last paragraph explained it very well, i.e., no two subs, even in the same class, should start experiencing damage at exactly the same depth. As Sniper stated, once below 350 in a Porpoise class sub, you start taking taking true risks. My question was if a Porpoise class sub was used all the time, how consistent is it that when going below 350 feet you'd start taking damage? I guess after his several tests, that pretty much answered my question.

Once below that "red line" you'll start taking a little bit here, a little bit there, until eventually integrity falls to pieces. The little bits here and there are the sub's way of telling you it's dying, you're too deep, you're breaking it, etc.

Appreciate it. Thanks.

[Zayphod]

I wonder if they have a test depth, like in modern boats or was it just the big red dont do that line, better known as crush depth. You can go past test depth by a decent margin in modern boats. Been there and done that.

It would seem like every boat would be a little different, the more you make, the more you tinker with the design. So it would be something that gets turned over to each new CO, kinda like this is her tendencies. Bubbleheads know their boat inside and out, have to for quals, and I would think that would be a keen piece of information.

How exactly is "test" or "crush" depth determined? Do they just figure x number of inches of steel should withstand y lbs of of pressure/square inch? Someone had to put that red line on the depth gauge.

[stillalearnin]

I wonder if they have a test depth, like in modern boats or was it just the big red dont do that line, better known as crush depth. You can go past test depth by a decent margin in modern boats. Been there and done that.

It would seem like every boat would be a little different, the more you make, the more you tinker with the design. So it would be something that gets turned over to each new CO, kinda like this is her tendencies. Bubbleheads know their boat inside and out, have to for quals, and I would think that would be a keen piece of information.
How exactly is "test" or "crush" depth determined? Do they just figure x number of inches of steel should withstand y lbs of of pressure/square inch? Someone had to put that red line on the depth gauge.

Well, you do know the round about of test, they give you that from the boat company that produced it. They know the composition of the materials used to make the pressure hull. It is given the steel used will bend a bit when you get to depth, and they know the theoretical limit of that steel. That would give you test depth. Your actuall crush depth would be from how many penetrations there are in the pressure hull,how fatigued the hull is, the temprature of the hull, and some other things I'm sure to be leaving out. So you would kinda have an idea of crush, and you would know that is the dont go there line. If you take her down slowly past test, with barelly any down bubble, you should be able to figure out the flickering lights.
and 50 to 100 meters to that and that would be the "Line". The thing to remember boat is that, even when you give the dive officer an order, it does take a little time ands space to accomplish. You need to leave some pad room. You might tell them " dive make your depth 500 feet" and if your going full tilt boogey, the will go to 500, but in the process they will dip a little below that trimming out the boat and if your crush is at 500, then yo might be screwed because the cow and the dive off and your people sitting the sticks make a small woops by 10 feet.

Hope this helps,

Derrek

[Zayphod]

Well, you do know the round about of test, they give you that from the boat company that produced it. They know the composition of the materials used to make the pressure hull. It is given the steel used will bend a bit when you get to depth, and they know the theoretical limit of that steel. That would give you test depth. Your actuall crush depth would be from how many penetrations there are in the pressure hull,how fatigued the hull is, the temprature of the hull, and some other things I'm sure to be leaving out. So you would kinda have an idea of crush, and you would know that is the dont go there line. If you take her down slowly past test, with barelly any down bubble, you should be able to figure out the flickering lights.
and 50 to 100 meters to that and that would be the "Line". The thing to remember boat is that, even when you give the dive officer an order, it does take a little time ands space to accomplish. You need to leave some pad room. You might tell them " dive make your depth 500 feet" and if your going full tilt boogey, the will go to 500, but in the process they will dip a little below that trimming out the boat and if your crush is at 500, then yo might be screwed because the cow and the dive off and your people sitting the sticks make a small woops by 10 feet.

Hope this helps,

Derrek

"We made it so it'll go to the test depth based on what we know about the thickness of the hull and the way we carefully welded everything together. We just won't guarantee you'll survive BELOW that depth. It MIGHT, because we might have put it together better than we thought we did, we just won't guarantee it." :yep:

That would explain why they could go past the "test depth" in the movies and still make it out alive, then. There's "theory" and then there's "real world", so to speak.

Thanks for the explaination.

[stillalearnin]

Pretty much. Like I said, every boat is different. They have souls of their own. Untill you learn her habits and quirks, you arent safe. Your shipmates arent safe. The boats not safe.