Visible underwater

[Binary101]

I dont have SH4, i like that the water is much more transprent, but i was just wondering i've seen some arial photographs of submarines at periscope depth and was wondering under what conditions are submarines visible underwater and at what depth will they not be visible, also were there any uboats sunk becuase they were spotted and tracked even underwater and can this be implemented into the game?

[Ducimus]

sunk becuase they were spotted and tracked even underwater and can this be implemented into the game?

Ive recieved quite a number of complaints having modded the game to do just that. :rotfl:

[DavyJonesFootlocker]

It's a bit unrealistic to me. If you're in clear, shallow waters maybe. Then there's light reflection/refraction from altitude to consider. Also visiblity- fog, etc. I placed a contract out on Duci for that.:yep::rotfl: Just kidding!

[Torplexed]

It wasn't uncommon in the Mediterranean and I imagine water conditions in the shallow South China Sea were similar. Gonna have to train my flak gunners to fight in scuba gear. ;) You should be safe in the deeper blue ocean tho.

[seafarer]

The open Pacific Ocean waters are remarkable clear. You can easily see objects several tens of feet below the surface on a sunny day, so I have no trouble imagining that a conning tower sitting a few feet below the surface would be clearly visible from above (remember periscope depth on the guage is keel depth).

And, while I cannot find it right now, one of the US Navy web pages has pics of a Los Angeles class boat at periscope depth taken from a supply helicopter coming to rendevous with them - you can clearly see the whole boat in detail below the surface (the pic was obviously taken on a nice clear sunny day, during some NATO exercise if I remember it correctly).

[DavyJonesFootlocker]

Yes, but that's just a selective case. What about in bad weather conditions and night? Unless the pilots got night vision goggles it's next to impossible unless the plane is flown a few feet and 4 mph from the surface, directly above the sub.

[Type941]

:ping: Looks pretty visible to me.

http://www.afcea.org/signal/articles/articlefiles/1054-Pic1-RRsilent.jpg


The USS Chicago, a Los Angeles-class attack submarine, glides along
at periscope depth in the western Pacific Ocean off the coast of Malaysia.

[DavyJonesFootlocker]

No. I meant that yes, in those conditions it can be seen, but what about less favorable conditions. Remember a helicopter took that one. A plane flying at 300 mph or more may not pick it up.

[Digital_Trucker]

:ping: Looks pretty visible to me.

<pic snipped to save bandwidth>


The USS Chicago, a Los Angeles-class attack submarine, glides along
at periscope depth in the western Pacific Ocean off the coast of Malaysia.

From what type of craft, at what altitude, at what relative speed to the sub and with what photographic equipment was that photo taken? Pictures don't always tell the story.:sunny: The fact that it's leaving a bit of a wake would help spotting, but notice that the angle of the shot is almost directly down on top of the sub in smooth water. Add a bit of an angle (so that more light is reflected off of the waters surface) and a bit more chop to the water (so that more light is refracted both on its way to the sub and its way back) and the sub would not be as visible.

The real problem is modelling (in game) a sensor that can duplicate (within reason) the human eye and brain's ability to detect an object underwater. The games visual sensors don't see underwater (unless you use a variable designed for something else to fool the sensor into seeing an underwater object, in which case you end up with a completely uncontrollable "x-ray vision" that is impervious to light/sea/depth conditions). So far, other sensors haven't worked either (yet).

[Ducimus]

The short of it its, in terms of undewater visual detection, you can control the RADIUS in which it is possible, just not the depth.

So by virtue of lowing a varible (exact name illudes me at the moment, short on sleep, groggy, still on 1st cup of coffee), you can make this detectioin radius larger. By raising this number, you can make the detection radius smaller.

Detection radius is important, because your giving the plane TIME to see you. For detection to occur, the AI must see X amount of your sub, for Y time. Since planes travel so fast, they can zip right though this radius before they can regester a sighting. So you can only make the detection radius so small. I think its around 3,000 meters is what i have it at.

The stop gap, was adding "Thermal Layer Signal Attenuation=5.0" to the visual sensor in the sim.cfg. At least, its hopped that works in stopping deep detection, if your below a layer.

These are the limitations imposed by the agme engine. When you make the game do something it wasnt orgianlly intended to do, its not going to work perfectly. But it works well enough, and the positive aspects to gameplay, far outweigh the occasional "WTF".

[MONOLITH]

You guys actually had a good discussion on this quite awhile ago, including some good pictures/diagrams of the radius issue. Wish I could find those right now...

Question Ducimus...

I assume the radius prevents you from being spotted, when you dive to a depth that puts the top of the radius underwater, yes? And can you say, in TM, about what that depth is, or do other factors complicate that being a simple answer?

[Major Johnson]

I would say that in real life the weather plays a big part of this equation. On a clear day and calm seas, I wouldn't be surprised to hear that a sub is visible down to 100 ft. In bad weather, ie, rain, chances are there's not going to be planes flying anyway. Another point was made about how high the plane is flying. Another good point, but for the sake of this game, I would say every plane is flying at a height normal for looking for subs. No point in having high level bombers. Also the cruising speed of most sub hunting planes wasn't 300 mph, it was normally around 200 or below. The 300 mph range is normally getting close to the top speed of the craft flying level. I recall seeing photographs of Uboats that were under the surface, taken by our own WW2 anti sub patrols. Many of those were taken by slow/low flying blimps, but there were also personal craft used for ASW as well. So I have no problem with planes being able to see a sub at periscope depth during ideal conditions.

On a side note, wasn't the Union ironclad "Monitor" found by a plane?? And I believe it was in 100 ft or so of water.

[capthelm]

:ping: Looks pretty visible to me.

http://www.afcea.org/signal/articles/articlefiles/1054-Pic1-RRsilent.jpg


The USS Chicago, a Los Angeles-class attack submarine, glides along
at periscope depth in the western Pacific Ocean off the coast of Malaysia.


sh4 models the ocean perfect imo..:sunny:

[Ducimus]

I assume the radius prevents you from being spotted, when you dive to a depth that puts the top of the radius underwater, yes? And can you say, in TM, about what that depth is, or do other factors complicate that being a simple answer?

Your aspect to the approaching plane, Sea state, light factor, and fog always complicate things from a simple answer. Sometimes they'll fly right by and not see you, other times they see you all too well.

[Binary101]

Thanks for the replys, I dont know much about game modding, but as you guys said under the right conditions, ie clear weather, say from 11am to 3pm and at what places on the map the uboats will be detectable at periscope depth, is there something in game that could monitor all these? graphicly you can see the uboats already underwater why so why cant enemy planes and would this be good in game?

[Munchausen]

graphicly you can see the uboats already underwater why so why cant enemy planes

:hmm: I think you're confusing reality with subroutines. The game engine has two parts: one, the graphics display (as seen, by you, on your monitor) and two, the underlying game world (as defined by numerous subroutines for ship behavior, environmental behavior, and artificial intelligence ... AI behavior).

The pilots of enemy planes cannot "see" what you see. They are, in fact, nothing but a lot of computer code ... mathematical definitions outlining a set of parameters ... in an attempt to approximate real life. If all the factors involved in spotting a submerged submarine could be crammed into this simulation, it would probably take a super-computer to run it in real time.

[Major Johnson]

The pilots of enemy planes cannot "see" what you see. They are, in fact, nothing but a lot of computer code ... mathematical definitions outlining a set of parameters ... in an attempt to approximate real life.

WHAT??? I guess now you're going to tell me there's no Easter Bunny!!!

MOMMY!!!!
:rotfl:

[Ducimus]

Well Binary101.....

As im sure you can tell, this has been touched on quite a bit in the past. Probably the most contraversial gameplay adjustment ive ever made. I think most like it, but theres definatly a number who don't. *shrug*

[Capn_Sinky]

I read on one of the online WWII Sub Commanders manuals thingys that standard procedures was during daylight hours in areas where aircraft were known to be patroling to maintain a depth of 140 feet. When I'm patroling near Japan I keep her at 150-200 feet at three knots. Can pretty much stay down during daylight hours. Come up at night to recharge and make up for lost time.

If you think about it, the only thing that CAN GET YOU during daylight hours that you can't pick up by sound first, is aircraft. It's also the only thing you can't shoot at while at periscope depth. :know:

[CinC Battleforce]

In the pacific several japanese subs were straffed by fighters off the CVEs. The FM-2 Wildcat of the VC squadron would fly a couple hundred feet off the surface of the ocean. They would sight a jap sub at periscope depth. In most cases the pilots brought back intel to the carrier clearly showing the sub in the water. They would start circling and straffing the sub. while TBM Avenger bombers came roaring in. the Avengers would drop a mix of depth bombs and Mk 24 Fito torpedos on the target. The clear water of the Pacific was often a disadvantage to the submarine.

[Ducimus]

I thoguht the very first picture on this page:
http://www.navsource.org/archives/08/08360.htm

was rather interesting.

[Sailor Steve]

Yes, it is. Never seen that one before. Thanks.

[odjig292]

I'm on Ducimus's side, although I don't like being sunk any more than the rest of you. Having flown over major portions of the South Pacific, it's amazing how clear the water is in some places. A sub at periscope depth could be seen.