At what distance for visual detection of periscope?

[Der Teddy Bar]

What distance on a flat sea should the persiscope be seen when over 1 metre above the surface?

Taking into consideration that your speed makes no difference to the AI's ability to see the scope, that is, at 5 knots your scope in no more visible than it is when you are at 1 knot.

My feeling is around 2000 to 2500 metres.

[Uber Gruber]

Not wanting to pirate the topic as its a very important question, so sorry in advance teddy, but do you or anyone else know how the game handles periscope detection ?

I assume the %age chance of detection increases as your u-boat nears an enemy vessel. I also assume that the u-boat would have to be within a certain radius of the enemy before there is any chance of detection. Finally, i assume that %age chance of detection is alse proportional to ammount of persicope above water and inversely proportional to sea state.

Can anyone clarify ?

Cheers.....

[don1reed]

You may be correct on a bright, cloudless, calm day; however, (obviously) add: overcast, calm before the storm, time of day, fog, haze, etc., will greatly shorten visible distance.

I know you've read and re-read your copy of the U-Boat Commander's Handbook 'til it's dogeared--keeping the objective lens awash and no larger than the size of a 'fist' above the surface.

I've been unable to find homemade, fisherman's shallows marking pylons in 'close' weather conditions at 100m that normally stand 2m at low tide...or, suddenly nearly collide with a ghost of a human in a bright yellow ocean-kayak. Who hasn't returned after the wx changed and coundn't find the can/nun/sea buoy to enter channel? There are exceptions.

rgds,

[caspofungin]

2-2.5 km seems a long way... i'd have thought more like <1k. from what i've read, irl what you spot is the wake/feather rather than the scope itself.

[Oesten]

2-2.5 km seems a long way... i'd have thought more like <1k. from what i've read, irl what you spot is the wake/feather rather than the scope itself.

This all depends on how SH3 calculates the scope detection.

If SH3 works on a 0% chance direct to 100% chance of spotting the scope (i.e. the AI never spots a scope over a certain distance, and always spots it under that distance) then the scope detection range needs to be low, no more than 1000m. Otherwise we'll have destroyers impossibly spotting scopes from 3 kilometers away!

If SH3 works on a rising percentage scale, e.g. at 2000m or more the AI will never spot the scope, at 1000m or more it will always spot the scope, and at ranges from 1000-2000m the AI has a percentage chance of spotting the scope (e.g. 10% chance at 1900m, 20% chance at 1800m, 30% chance at 1700m and so on) then the value Teddy Bar is talking about is either the highest or lowest value of the detection ranges.

In this case, the value should either be 2000m (highest) or 1000m (lowest).

[Uber Gruber]

So does anyone know the answer ? I mean how SH3 currently does it ?

[Der Teddy Bar]

The way that detection works is simply on a surface area, Enemy surface factor=. Your speed appears to have no effect as the periscope detection tests was no different at 2 knots to that of 5 knots.

The default value is 400, or an area equal to 20 * 20 metres... that is a lot of u-boat.

This is tempered with considerations such as wave height, light conditions, fog, sensitivity and detection time.

So a visual sensor on an escort with a high bridge will see you well before before a elco would.

that said, if the surface area is less than the Enemy surface factor= then it is completely blind to your presence.

As an example, I have moded the visual so that you can expect to be possibly detected at these ranges with this much scope above the water...
Under 2500 metres extended 3 metres
Under 2000 metres extended 2.5 metres
Under 1400 metres extended 1.5 metres

The issue is the persiscope is completely invisible to the AI with the scope at 1 metre above the water, even when you are within 100 metres of the escort.

It can be done that at 300 metres with 1 metre of periscope above the water you will be detected, but then we need to consider the affect that this will have on you being detected at long distances on the surface.

All my testing has been in perfect 0mps conditions and it may be that the effects of your u-boat not keeping precise depth in 5mps will be enough balance the lack of detetcion at a 1 metre extension.

[Uber Gruber]

Interesting teddy, thanks. I'm pleased that using my periscope well will help me not get detected rather than simply being up against a random number generator.

I see what you mean about the 1M problem. It will be interesting to see the results after testing in worse weather conditions.

I look forward to this.

[Der Teddy Bar]

Well, we have removed the 1 metre issue.

It appears that the detection of the scope varies upon the AI state, that is, when not aware of you, the AI takes longer to respond to your periscope where as when it knows that you are there it will respond quicker.

Hard to say on the sea state as that has yet to be configured.

You can now expect that you u-boat will be detected at greater distances on the surface by escorts, again the height of the sensor is important. For example, the Dido reacted at 5800 metres and the trawler at 4400 metres in perfect weather.

I would expect that these values may be on the short side for a sunny day and no winds...

While not perfect, now your speed will make a difference to your possibility of being detected. The not perfect part if at XXXX distance your periscope at 2 metres above the surface is detected at 5 knots, now if you slow down to 2 knots the detection will reduce and/or go away. While not realisitc it is better than nothing.