At what distance can my sub be spotted
 

I’ve heard 6 miles is the distance my boat can be spotted by an aircraft. At what distance am I safe from being spotted by other surface ships day and night? At what distance will they spot my periscope?

it depends on the mod-set you are using.
since you didn't share that, let's use the 1.5 UBM Stock version as our example.
two other factors influence your detection: the weather, and the skill of your enemy.
Six miles is a good rule-of-thumb for ships and shore batteries during the day. Night time detection will be less than 6 miles. in my experience, shore batteries have sharper night vision than ships. at night, depending the skill of enemy, you could get within a couple of miles (4000 yds) of an enemy ship/convoy. some Kaleuns relate experiences where they mimic WWII skippers in their night SURFACE torpedo attacks on a convoy. this would be tough to accomplish, IMO. you will have to go out and have your own experiences.


scope detection also depends on the three variables mentioned above as well as your speed. more speed makes your scope wake more visible.
you should try to keep your scope observations to 30-45 seconds. it takes practice.
as far as distance is concerned, probably under 2000 yds...depending on speed.
when you are within 1000 yds, expect to be visually detected in about 10-15 seconds. if you exceed that time, you will take fire and sometimes that fire will sink you.

good luck, Kaleun Prozac.
:Kaleun_Salute:

There's a post around here in tips and tricks that outlines this; I'll try to provide the summary. There are basically two bubbles around a ship - the "possible" bubble and the "probable' bubble. The size of the possible bubble I think is hard locked, for instance merchants cannot spot beyond 7nm. The probable bubble is basically the center of the bell curve...I think for merchants its around 5000 yards on a normal day for a normal sub target steaming at a non excessive speed etc, for warships it's a bit further out - 8000 maybe? The key here is that while you "probably" won't be spotted at 5nm by a merchant, you could be.