Decks awash and depth Control

[brianodww]

Will there be an update to model this properly? In games such as silent hunter and wolf pack, decks awash is definitely a key feature to night attacks. But in U-boat your crew abandons the tower and you are forced to use a periscope. This kind of kills the immersion for me, any update would be greatly appreciated.

[Dewgle]

As it turns out, decks awash was not a thing that U-boats did. At least, not in the way that you're thinking.

It was verboten to leave the hatch open or to have men on the bridge when the ballast tanks were flooded. The U-boat becomes too unstable and the chance of water flooding in through the hatch were too high. As were the chance of men getting swept away or drowned (if they were wearing harnesses).

Yes, Otto Kretschmer would often attack at night while surfaced. But he was not decks-awash when he did it. His ballast tanks were empty.

U-boats did surface with their tanks still partially flooded though. They would then start up the diesels and used the exhaust gasses to blow the rest of the water out of each of the ballast tanks. This allowed them to save compressed air (minimizing the time needed to run the air compressors).

And served to coat the interior of the ballast tanks in soot-oil from the diesel exhaust which protected steel from rust and prolonged the life of the ballast tanks between maintenance intervals.

But history lesson aside, yeah I like decks awash too. It's a nice stop-gap to use before you get the snorkel to replenish your oxygen and maybe recharge the batteries by running on diesels.

It may not be realistic to cruise along at decks awash as it was primarily used when surfacing the boat. But it's more realistic at least than having men on the bridge while running decks awash, as that was definitely not something they did, and was not safe.

[brianodww]

Originally posted by McDewgle:

As it turns out, decks awash was not a thing that U-boats did. At least, not in the way that you're thinking.

It was verboten to leave the hatch open or to have men on the bridge when the ballast tanks were flooded. The U-boat becomes too unstable and the chance of water flooding in through the hatch were too high. As were the chance of men getting swept away or drowned (if they were wearing harnesses).

Yes, Otto Kretschmer would often attack at night while surfaced. But he was not decks-awash when he did it. His ballast tanks were empty.

U-boats did surface with their tanks still partially flooded though. They would then start up the diesels and used the exhaust gasses to blow the rest of the water out of each of the ballast tanks. This allowed them to save compressed air (minimizing the time needed to run the air compressors).

And served to coat the interior of the ballast tanks in soot-oil from the diesel exhaust which protected steel from rust and prolonged the life of the ballast tanks between maintenance intervals.

But history lesson aside, yeah I like decks awash too. It's a nice stop-gap to use before you get the snorkel to replenish your oxygen and maybe recharge the batteries by running on diesels.

It may not be realistic to cruise along at decks awash as it was primarily used when surfacing the boat. But it's more realistic at least than having men on the bridge while running decks awash, as that was definitely not something they did, and was not safe.

Oddly enough I have seen this sort of copied and pasted else where in the discussion. I actually have read werner's biography, in regard to night surface attacks. It was mentioned on more than one occasion where decks awash was used in such a manner. So I do not fully agree with the "not realistic" standpoint. But cool information nonetheless.

[Dewgle]

Originally posted by brianodww:

Oddly enough I have seen this sort of copied and pasted else where in the discussion.

Aye, that would probably be me and Stoss that you've seen saying that. It's hard work correcting misconceptions :P

Like did you know the blue light isn't historically correct? It was used on subs and surface ships, usually in berthing compartments and the sonar shack but not until after WWII.

But it was made iconic in the movie Das Boot and I believe that's why the devs included it, as a fond little nod to the movie. Not relevant to the topic at hand but still true.

[(KRA)Gray Wolf 3rdX0]

I never used decks awashed my self only when proving I was never surfaced when geting guned to hell at parascop depth.

[derstosstrupp]

It was possible. BUT only in perfect conditions. In that state, with the top deck underwater, a U-boat is very unstable and vulnerable to rolling. Perfectly calm seas, or areas like fjords would be OK. In all the KTBs I’ve read (and that’s a lot), I’ve only come across one instance, U-995 in a Norwegian fjord.

Iron Coffins is rife with translation and factual errors and not a good source in English. At best, they “flooded down”, but not so far that the top deck was underwater. Very dangerous condition.

[brianodww]

Originally posted by McDewgle:

Originally posted by brianodww:

Oddly enough I have seen this sort of copied and pasted else where in the discussion.

Aye, that would probably be me and Stoss that you've seen saying that. It's hard work correcting misconceptions :P

Like did you know the blue light isn't historically correct? It was used on subs and surface ships, usually in berthing compartments and the sonar shack but not until after WWII.

But it was made iconic in the movie Das Boot and I believe that's why the devs included it, as a fond little nod to the movie. Not relevant to the topic at hand but still true.

Haha thats an interesting fact. Good to know

[brianodww]

Originally posted by derstosstrupp:

It was possible. BUT only in perfect conditions. In that state, with the top deck underwater, a U-boat is very unstable and vulnerable to rolling. Perfectly calm seas, or areas like fjords would be OK. In all the KTBs I’ve read (and that’s a lot), I’ve only come across one instance, U-995 in a Norwegian fjord.

Iron Coffins is rife with translation and factual errors and not a good source in English. At best, they “flooded down”, but not so far that the top deck was underwater. Very dangerous condition.

Interesting point, even so it would be helpful to not have to leave the deck fully. Appreciate the response. Have you read otto kretschmer by lawrence paterson?

[derstosstrupp]

Originally posted by brianodww:

Originally posted by derstosstrupp:

It was possible. BUT only in perfect conditions. In that state, with the top deck underwater, a U-boat is very unstable and vulnerable to rolling. Perfectly calm seas, or areas like fjords would be OK. In all the KTBs I’ve read (and that’s a lot), I’ve only come across one instance, U-995 in a Norwegian fjord.

Iron Coffins is rife with translation and factual errors and not a good source in English. At best, they “flooded down”, but not so far that the top deck was underwater. Very dangerous condition.

Interesting point, even so it would be helpful to not have to leave the deck fully. Appreciate the response. Have you read otto kretschmer by lawrence paterson?

I haven’t, I’ll definitely look for that though!

[boris.glevrk]

I thought deck awash is for using both diesel and hydrophone (before you have snorkels, of course)?
I tried it and it seems that hydrophone doesn't work with deck awash...

I do have snorkels but in rough seas they would switch between diesel and electric and thus stopping the boat, so I was hoping that at least in rough seas I can do deck awash and still retain diesel plus hydrophone...

[wolf310ii]

Originally posted by McDewgle:

As it turns out, decks awash was not a thing that U-boats did. At least, not in the way that you're thinking.

Like i said in the other thread, you are mixing up two different things.
Using the diesel or not, when surfacing they never blow the tanks fully (only in case of an emergency) until they are on the surface. Then they blow one tank after another (with air or diesel) until bubbles rised on the side of the boat, wich showed that the tank is empty, and close the flood valves.

For deck awash, they dont blow the tanks partially (that would make the boat even more unstable), they flood some tanks and left some empty, like flooding tank 5 (bow) and 1 (aft) or tank 3 (center).

It was verboten to leave the hatch open or to have men on the bridge when the ballast tanks were flooded.

It was the other way around, it was forbidden to start diving (flooding the tanks) until the boat was ready to dive (diesel off, air intakes closed, hatch closed, ect.). For that reason only the commander or the LI gave the order "dive", not some random guy like in the movie.
There was an exception to that, expierienced crews where allowed to flood tank 5 immediatly on alarm, to dive faster.

But history lesson aside, yeah I like decks awash too. It's a nice stop-gap to use before you get the snorkel to replenish your oxygen and maybe recharge the batteries by running on diesels.

This is the unrealistic part

It may not be realistic to cruise along at decks awash as it was primarily used when surfacing the boat. But it's more realistic at least than having men on the bridge while running decks awash, as that was definitely not something they did, and was not safe.

traveling deck awash, was way too dangerous. If the bow cut under a wave, the boat could unintendet dive serval dozen meters (even with empty tanks in heavy sea), because the flat deck act like a dive plane.
Also deck awash slow the boat down and cost more fuel.

But for short times, in calm sea, it was done to mask the siluette, with men on the bridge.

Originally posted by derstosstrupp:

It was possible. BUT only in perfect conditions. In that state, with the top deck underwater, a U-boat is very unstable and vulnerable to rolling. Perfectly calm seas, or areas like fjords would be OK. In all the KTBs I’ve read (and that’s a lot), I’ve only come across one instance, U-995 in a Norwegian fjord.

Iron Coffins is rife with translation and factual errors and not a good source in English. At best, they “flooded down”, but not so far that the top deck was underwater. Very dangerous condition.

Deck awash means not nesseccesarily deck under water, waves constant rolling over the deck is already deck awash.

Also you will find deck awash in KTBs only if the commander thought it was note worthy, they wrote (mostly) only important thinks in the KTB.

Originally posted by boris.glevrk:

I thought deck awash is for using both diesel and hydrophone (before you have snorkels, of course)?
I tried it and it seems that hydrophone doesn't work with deck awash...

And this correct so, with the diesels running the hydrophone hears nearly nothing.
Also so close to the surface, the waves create a big sonar shadow, so even with the diesels off, u-boats couldnt hear much.
And depending on your hydrophon, the hydrophon is not even under water on deck awash. The KDB is the mast on deck you can see in the background picture.
The GHG is aranged around the forward dive planes.
And the Balkongerät is a "dome" on the lower bow, and has the best chances to hear something at deck awash

[derstosstrupp]

True. Regardless, it a dangerous state to operate in, and wasn’t generally done. “Flooding down” yes, but not operating with decks underwater while underway, which is what people mean when they say “decks awash” in subsimming.

[brianodww]

Originally posted by boris.glevrk:

I thought deck awash is for using both diesel and hydrophone (before you have snorkels, of course)?
I tried it and it seems that hydrophone doesn't work with deck awash...

I do have snorkels but in rough seas they would switch between diesel and electric and thus stopping the boat, so I was hoping that at least in rough seas I can do deck awash and still retain diesel plus hydrophone...

It depends on which hydrophone you are using. If it is the one that is mounted on top (KDB) then it wont work. But if you are using the GHG, it technically should...but I dont believe that is modelled in game. I will say this though, using it on the surface would not be helpful, too much ambient noise. I am able to switch to diesel when decks awash, so I do not know why you are unable to.