Decks awash: A scam?

[IonicRipper]

I was reading this article... Here's what they said about decks awash:

"If the center of gravity and the center of buoyancy are coincident and if a wave were to hit the boat from the side, capsizing could occur. Those Hollywood movies where a submarine is shown with decks awash, making an approach on the surface is mostly fiction. That is about where the two centers become coincident and it doesn't take much to roll the boat over."

Apparently (according to this article) they never used decks awash in WWII.
Can someone confirm? (Or refute.)

The article in question: http://www.subvetpaul.com/Flt_Class_Sub.html

[Cybermat47]

I'm not sure if the U-boat aces had decks awash, or just stayed on the surface. And is the article talking about USN Fleet Boats and U-Boats?

[Sailor Steve]

They're talking strictly about US boats, but the problems would be about the same either way.

I know that night surface attacks were common, but I have no clue about decks awash. It will be interesting to see what comes out of this.

[troopie]

I've read the same thing elsewhere from a (now forgotten) different source. I believe it, but can't get my head around the physics of it; surely the boat would be more top heavy the higher it is out of the water? Personally though, I never use decks awash; feels like a cheat to me. Surely the increased drag travling that way would've been undesirable? Also, I'm unsure If any in-game advantage is gained, I mean, do other units register that you're sitting a little lower in the water, or simply that you're surfaced?

[Sailor Steve]

Originally Posted by troopie

...surely the boat would be more top heavy the higher it is out of the water?

When the tanks are empty the major weight involved is the keel, which is designed to keep the ship upright. With the ballast tanks full the boat now has more than 350 tons of water on board, most of it in outboard tanks level with the boat's normal waterline. Once submerged the center of gravity is balanced, but surfaced it looks like any serious ocean motion could possibly be catastrophic. I don't know if that's true or not, but now that I think about it I see how it could be possible.
http://www.maritime.org/fleetsub/chap4.htm

Personally though, I never use decks awash; feels like a cheat to me. Surely the increased drag travling that way would've been undesirable?

Running all over the ocean with no penalty is certainly a cheat, since the game allows it to work when in real life fuel consumption would rise dramatically. The main idea would be to use it only to lower the profile in a night surfaced attack, and to facilitate diving quickly in the same situation. Also the game assumes you're surfaced, and since you have no control over which engines you use you are automatically running on diesels, when part of the point in a surfaced attack is not to be heard as well as not being seen you would certainly be running on batteries in that situation.

Also, I'm unsure If any in-game advantage is gained, I mean, do other units register that you're sitting a little lower in the water, or simply that you're surfaced?

I don't know that one either.

[Bilge_Rat]

That is certainly an interesting question and one which has puzzled me for a long time.

Running "Decks Awash" in the sense of having the decks underwater with only the Conning Tower above water does not appear to have been used in attacks. Blair's three books on ww2 sub warfare does not mention an attack with "decks awash" (i.e. decks underwater). The Official manuals, i.e. the 1943 German sub commander's handbook and the 1946 U.S. Fleet submarine manual also do not discuss this attack tactic.

Without delving into the difficulty of maintaining a sub level in the open ocean with decks underwater, there would also appear to be little tactical advantage. A submarine is already hard to spot. The hull which is only a few feet above water is very hard to spot. The Conning Tower is also hard to spot from the lookout station/deck of a typical freighter since it usually is below the horizon. There would not appear to have been a big advantage in concealment in running with decks under water.

There also seems to be a confusion as to what "Decks Awash" means. Some submarine which were recorded as "running decks awash" had their decks above water, but had some seawater already in their ballast tanks so they could dive more rapidly. Their decks would be above water, but lower in the water than normal. For example:



HMS B11 running "decks awash".

http://en.wikipedia.org/wiki/File:HM...ecks_awash.JPG

I suspect most submarines which recorded in their logs that they were running "decks awash" actually had their decks above water.

[Claves_Mortis]

Originally Posted by troopie

Also, I'm unsure If any in-game advantage is gained, I mean, do other units register that you're sitting a little lower in the water, or simply that you're surfaced?

For every surface attack I will go to a depth deep enough to just allows me to get on the bridge / UZO. I am doing this because obviously everything "on top" of a wave / the water is affected more by the waters movement than everything "inside" the wave / water is, meaning that if you are as deep as possible (while still being able to use the UZO) you can use the advantage of the x7 magnification while reducing the shaking part caused by waves, being able to do more precise usage of the UZO.

I do not know if that is historicaly correct, but in Silent Hunter 4 it does work (for the more steady view). If you do live at the sea you can easily try that yourself: get into a small, light (somewhere around 2-3 meters in length will be a size where you can easily realize it) without any equipment and only yourself in it - shaky. If you get your outbord motor, your gas tank, anchor, chord, some friends and maybe some water in your boat, resulting in lying deeper in the water the waves won't shake the boat as much anymore and the boat will also be less affected of your movement (leaning from left to right for example), it will still move, but slower and more predictable.

I also have no idea if it affects the ability of how easily the submarine is spotted by other ships in the game, but as how far your periscope does stick out of the water does affect the chance of being spotted (I am pretty sure about that, but it's only what I feel / experience, no written prove for that), I could imagine how far the tower is above the water does count too.

[IonicRipper]

I remember conducting a surface attack on a lone merchant on a fairly clear night with decks awash at approximately 1200 yards. My first shots missed (i think i miscalculated the torpedo depth) but he never spotted me or the torps so it gave me a chance to recalculate and ultimately, skin him. I should have saved the game and try the same thing fully surfaced to see if would have spotted me. I might try that with the mission editor some time today. I'll keep you guys updated.