Why do destroyers have short detection ranges?

[Skeksis]

Reading up on this, a 30m high crow nest has horizon view of 20km, so from a battleship why can’t destroyers visible at 20km?

Second Point.

Detection seems to be back to front. At present the approaching ship has the determination of detection but shouldn’t the detection range be based on the visual capability of the focus ship. E.g. the ships mast/crow nest/tower height (and/or radar), sets the horizon visual range, this then determines the approaching ship detection range.

Any insights? 

Edited February 3, 2020 by Skeksis

[SmoCro]

How far the horizont is away is not how far you realistically can see things.

I have a castle near my home, on a good day I can see for 150 kilometers.

But I cannot see houses. I can only see cities.

Even with a glass it is just a blotch.

And this is over land.

Over the sea there is water vapour.

Always some.

And that breaks light.

A destroyer might very well be completely in the lower quite opaque levels of water vapour making it "invisible" until it is well within your horizon.

By comparison substantial parts of the battleships would be out of that layer, allowing the destroyer to spot from farther away than the other way around.

[Skeksis]

4 hours ago, SmoCro said:

I have a castle near my home, on a good day I can see for 150 kilometers.

Exactly, high up on the castle you see 150km but on the beach, at sea level, your horizon range is sufficiently reduced, thus it’s not the city's detection range, it's yours.

4 hours ago, SmoCro said:

A destroyer might very well be completely in the lower quite opaque levels of water vapour making it "invisible" until it is well within your horizon.

Sure weather would diminish detection with either setup but surely with ship optics they would pick the target at 20km. 

Edited February 3, 2020 by Skeksis

[akd]

The differences in visibility are grossly exaggerated in game currently, just as is the distance various ships can see with towers that are all of similar height.  Visual detection should depend more on visual conditions and less on the object observed.  That difference should play more of role around the margins of visual detection.

[Cptbarney]

19 hours ago, akd said:

The differences in visibility are grossly exaggerated in game currently, just as is the distance various ships can see with towers that are all of similar height.  Visual detection should depend more on visual conditions and less on the object observed.  That difference should play more of role around the margins of visual detection.

True, whether it being cloudy, fog, mist, sunny, clear or night, should help to greatly increase or decrease the visibilty of all ships, plus also which side has better visual equipment too.

That way weather becomes more important and integral to watch for when fighting (more so in big naval engagements).

[Knobby]

Another big factor of visibility is contrast, wether an object is silhouetted against the horizon or not or is a significantly different color from the surrounding makes a massive difference. Why do you think most navy vessels are painted gray?

 

In this case a destroyer that doesn't break the horizon could be less detectable than a battleship that does, even if the destroyer is actually closer.

In the extreme size difference example, there are many anecdotal examples of shipwrecked survivors on floating debris or even half sunk ships or brightly colored rafts that could clearly see passing ships in the distance while never being spotted themselves.

Thus it makes sense that at a certain distance a destroyer would be able to spot a BB while the BB might not be able to detect the DD, even though they are the same distance from each other and the BB has taller masts.

Now I can't comment wether the current implementation in the game is realistic because I haven't really payed attention to it in detail.

Edited February 3, 2020 by Knobby

[Skeksis]

@Knobby Found this…

Table 1, which indicates the maximum range at which an observer 100 feet above the waterline on a ship (called "own ship") can see another ship (called "target") of a given height above the waterline.

Target Height(ft)	Range (yards)
10	30700
20	33600
30	36100
40	37900
50	39700
60	41300
70	42800
80	44200
90	45400
100	46600
110	47600
120	48900
Table 1: US Navy Table of Maximum Range Assuming a 100 foot Rangefinder Height and Variable Target Height.

 

Destroyers are actually quite large, game scales can be confusing or can give the perception that they are tiny, they aren’t. Given the table above, at 20km and on a clear day Destroyers will be visible.

[Shaftoe]

@Skeksis Just keep in mind that time of day (or, to be more precise, lightening), weather, water vapour and sea state can drastically affect visibility. And you can't count it to always be clear and nice. If anything, sea in UA:D often seems quite rough. 

[Skeksis]

18 minutes ago, Shaftoe said:

@Skeksis Just keep in mind that time of day (or, to be more precise, lightening), weather, water vapour and sea state can drastically affect visibility. And you can't count it to always be clear and nice.

Yeah I know, variants after the fact, and the fact (and topic) being the mechanic at default detection.

Quote

If anything, sea in UA:D often seems quite rough. 

Another topic though but I agree, given the true height of freeboards we always get wild waves washing over the aft deck.

Edited February 4, 2020 by Skeksis

[Cptbarney]

Another thing that annoys me about dd's or ships in general is when they prevent you from turning into torpedos or even try to actively avoid other ships, would be nice if you could set that collision thing for friendlys in formation and off for enemy ships.

That way my ships don't commit suduku into 18inch eletric torps lol.

[SmoCro]

The table mentions a rangefinder... don't rangefinders usually have magnification?

 

Edited February 4, 2020 by SmoCro

[akd]

They are not search devices, nor useful for that purpose.  Until radar comes along, the primary means of search is Mk. I eyeball aided by binoculars (and as such there is not significant differences ability across the time frame or between nations.  Look here for US Navy 1943 lookout manual:

https://www.history.navy.mil/research/library/online-reading-room/title-list-alphabetically/l/lookout-manual-1943.html

It's really down to training, height of observation and visual conditions, nothing else.

Edited February 4, 2020 by akd

[Skeksis]

20 minutes ago, akd said:

They are not search devices

Would you say any eyeball can spot smoke plumes and then the rangefinder is directed.  

Quote

https://www.history.navy.mil/research/library/online-reading-room/title-list-alphabetically/l/lookout-manual-1943.html

A quick read (skim over) of that article and there doesn’t seem to be anything on how visible ships are at 20km or any range, just sailor experience with distances.

 

Edited February 4, 2020 by Skeksis