Naval region coverage and detection chance - crunching numbers

[Vidkjaer]

When placing a fleet on a mission in a naval region the fleet gets a formation spread value:

• Patrol - 160%
• Search and destroy - 50%
• Convoy raiding - 120%
• Convoy Escort - 90%

When looking at the fleets detecting value this spread percentage determines which coverage the fleet has in a naval region. The coverage is not the same for all naval regions. Apparently naval regions has different seizes. So a fleet in the North Atlantic ridge has a (negative) -65,5% region coverage when set on Convoy raiding while the same fleet in the Eastern North Sea has +3,9% region coverage. This value together with some technology gives the fleet a separate detection chance for surface vessels and subs.

The thing i would like to ask about is:
This region coverage percentage is the same whether the fleet is only 1 sub og 20 subs. So the detection chance end result - is that the average value per naval vessel in the fleet? So if i have 5% detection chance, would i then have 100% detection chance with 20 subs?
The tooltip states at the bottom the the ship states like surface detection and visibility comes into play for the true detection chance.
Could it then be the detection chance end result is a multiplier to the sum of the submarine fleets surface detection value. If my submarine fleet has 100 stat in surface detection value, then the end result would be 10 stat for surface detection if my detection chance is 10%?

How comes it into place regarding the surface visibility of enemy ships? How is is calculated?
I want a formula explaining it.
I cannot play the game if i dont know the rules.

What is the visibility stat for a convoy ship?

 

[sterrius]

What is the visibility stat for a convoy ship?

http://www.hoi4wiki.com/Naval_units

Convoy have 10 surface visibility, 5 sub detection and 5 surface detection with a speed of 15 knots and 30hp.

Im going to run some tests on the sunflower path about how many ships i need for a specific region and repeat that formula for other ones. Gonna take a while.


EDIT: got it how it works. Now i need some time to explain this in a simple manner for everyone to understand .

 

[sterrius]

@Vidkjaer


Ship Detection system.

The key is 4% detection.

The formula is.

(4% + Radar + Air coverage) * Region Coverage * Surface detection

4% + 0 (radar) + 0 (Air coverage) + (4 * 1,07) = 8,3%
Sub detection = Surface detection * (100% + 200%(Sub detection) 8.3% * 300% = 24,9%


Now the little tricks.

- Each fleet have its own detection chance. (So more fleets you roll more times for a chance to find the enemys).

- Surface and sub detection is counted by each Ship TYPE. (If you send 1 or 1000 subs it will change nothing, but add a destroyer and the detection is going to improve because destroyer is a nother type of ship).

Surface detection 10 = 0%. +1 = +10% surface detection chance.

Surface detection by ship. (1922 versions, it only goes up from there)

Battleships = 50%
Destroyers = 200%
Light cruiser = 50%
Heavy Cruiser = 20%
Battlecruiser = 20%
Submarines = 0% (yes, they suck at finding things above the water).

Sub detection works the same way. Just different numbers.

Destroyers = 400%
Submarines = 200%
Light cruiser = 100%
Everything else = -50% (yes, they give a penalty to hunt subs).


When you add different kinds of ships merge.
Add each type of ship. (lets say a Destroyer, Light cruiser and Heavy cruiser).
200% + 50% + 20% = 270%

Divide now by the type of ships. (3) 270%/3 = 90%

How that detection work? Likely it the % to find something that day. (So to find the hour % chance you need another calculation i really don´t know).

This is just a glimpse. So you now can try to test yourself and find the best ship formations to find ships and hunt subs .


This test only made me sure that improved ships are essential to find enemys. Also doctrine as they give huge bonuses to the chance of finding something.

 

[Vidkjaer]

Could you point me to where these formulas are in the game files?
I dont understand why a BB is better than a sub to find a surface vessel? A Sub has a higher 1936 stat for surface detection than a BB.
It seems odd to me that sending 1 sub or 1000 subs does detects a surface vessel on the same level.

 

[Secret Master]

IF you want to find things send a lone BB on Patrol! (You can send a doomstack to the same region, they will await the BB to find something and rush to help him). Another cheaper way is to send a group of destroyers.

If you want to find subs just send a group with destroyers and nothing else.

I've already been sending DDs in batches by themselves to hunt subs. I knew this works well.

But it surprises me that the game is set up so that a lone BB has better detection than a BB with some supporting ships. No one sent BBs out alone intentionally. Even Bismark ran with Prinz Eugen.

 

[rcbricker33]

I thought that the BB stats were off and they were going to get fixed... I could be remembering the thread improperly, but I thought I saw a thread where it was discussed.

 

[Adar1]

My basic idea is to reduce the size of naval provinces + sensible rise of detection values and capabilities for each vessel + get rid of dependence on strat regions for giving orders - for fleets and ships only not airplanes;

with the scope to get rid of all this non sense - regarding detection, mauled by an excessive indetermination of vessel's position in the big area;

@sterrius,.......

 

[Traks]

BB got fixed in patch 1.2, page 13 I believe with additional path notes which were missed in original patch notes statement.

 

[sterrius]

Could you point me to where these formulas are in the game files?
I dont understand why a BB is better than a sub to find a surface vessel? A Sub has a higher 1936 stat for surface detection than a BB.
It seems odd to me that sending 1 sub or 1000 subs does detects a surface vessel on the same level.

Remember doctrines and later designs of subs improve their chance to find something A LOT.

I used 1922 numbers with 0 doctrines researched.

Subs can get up to 250% in finding surface vessels. (1944 versioN).
Also germany doctrine for example give +90% surface detection to subs. (And raiding coordination making them reach and leave the battle faster).

I've already been sending DDs in batches by themselves to hunt subs. I knew this works well.

But it surprises me that the game is set up so that a lone BB has better detection than a BB with some supporting ships. No one sent BBs out alone intentionally. Even Bismark ran with Prinz Eugen.

Yeah, i find this a little strange too. But its how the work function. I would send the BB with destroyers to avoid them being killed by submarines before the main fleet arrive to save him. (its a huge drop but i can survive with a +860% find chance in 1922).

I thought that the BB stats were off and they were going to get fixed... I could be remembering the thread improperly, but I thought I saw a thread where it was discussed.

After you said that i looked at the 1936 and you're right. ITs a big.

1936 BB surface detection is 15. (+50%).

Making the destroyer the king in finding things. I changed in my topic because it was fixed in 1.2

 

[Miaow]

I think your post needs more editing: having the paragraph about lone BB right after the fixed stats looks weird and confusing.

Nice concise explanation otherwise.

 

[Secret Master]

After you said that i looked at the 1936 and you're right. ITs a big.

1936 BB surface detection is 15. (+50%).

Making the destroyer the king in finding things. I changed in my topic because it was fixed in 1.2

So, with the BB detection glitch in 1.2 fixed, we're back to DDs being prime detectors, not the Lone BB.

 

[Miaow]

Which is better. Although carriers and land-based air should be the very best detectors, followed by DDs then cruisers.

 

[sterrius]

Which is better. Although carriers and land-based air should be the very best detectors, followed by DDs then cruisers.

Carriers only if you place some planes in the air region to find units. If you do that those planes will not participate into the battle.

 

[Axe99]

Which is better. Although carriers and land-based air should be the very best detectors, followed by DDs then cruisers.

Cruisers with float planes (quite a few of them during the period) would have been better than DDs in a lot of cases. They've also got higher spotting positions, so can see further.

 

[billcorr]

Although carriers and land-based air should be the very best detectors, followed by DDs then cruisers.

Just wondering, what is the surface detection and sub detection of Naval Bombers?

Sterrius, great summary of the math behind ship and submarine detection. My multiplayer team-mates were doubtful that land based radar helped detect ships at sea...but now we know!

 

[sterrius]

What i find odd is that naval bombers do not increase the chance to find ships.

Only air superiority that must be done with light or heavy fighters.

Tested this by the way.

So i don´t know the chance of a plane finding a ship... maybe it uses the % chance of air combat. (In that case would be 1%/day + radar chance),

 

[Antediluvian Monster]

Cruisers with float planes (quite a few of them during the period) would have been better than DDs in a lot of cases. They've also got higher spotting positions, so can see further.

Yup. And the same applies to battleships as well. In addition the larger ships have more pairs of eyes and tend to have more equipment, such as radar sets.

Even disregarding aircraft the spotting strength of individual unit from best to worst should be largest to smallest. Destroyers and cruisers should shine in the amount of hulls you can put in water instead. They should be IC effective for spotting, that is.

 

[Dalwin]

@Vidkjaer


Ship Detection system.

The key is 4% detection.

The formula is.

(4% + Radar + Air coverage) * Region Coverage * Surface detection

4% + 0 (radar) + 0 (Air coverage) + (4 * 1,07) = 8,3%
Sub detection = Surface detection * (100% + 200%(Sub detection) 8.3% * 300% = 24,9%


Now the little tricks.

- Each fleet have its own detection chance. (So more fleets you roll more times for a chance to find the enemys).

- Surface and sub detection is counted by each Ship TYPE. (If you send 1 or 1000 subs it will change nothing, but add a destroyer and the detection is going to improve because destroyer is a nother type of ship).

Surface detection 10 = 0%. +1 = +10% surface detection chance.

Surface detection by ship. (1922 versions, it only goes up from there)

Battleships = 50%
Destroyers = 200%
Light cruiser = 50%
Heavy Cruiser = 20%
Battlecruiser = 20%
Submarines = 0% (yes, they suck at finding things above the water).

Sub detection works the same way. Just different numbers.

Destroyers = 400%
Submarines = 200%
Light cruiser = 100%
Everything else = -50% (yes, they give a penalty to hunt subs).


When you add different kinds of ships merge.
Add each type of ship. (lets say a Destroyer, Light cruiser and Heavy cruiser).
200% + 50% + 20% = 270%

Divide now by the type of ships. (3) 270%/3 = 90%

How that detection work? Likely it the % to find something that day. (So to find the hour % chance you need another calculation i really don´t know).

This is just a glimpse. So you now can try to test yourself and find the best ship formations to find ships and hunt subs .


This test only made me sure that improved ships are essential to find enemys. Also doctrine as they give huge bonuses to the chance of finding something.

This fits what I have been seeing with subs in 1.2.0

A small fleet of uboats (5-10) will still mangle an unescorted convoy now. The small wolfpack if engaged by enemy boats actually lsoes fewer subs (is more eager to disengage quickly). These two points combined with your calculations on detection clearly imply that one should not deploy subs in packs of 30-40. One should spread then in packs of 15 or so even if this means that many will not have commanders.

Mulitple packs in the same zone will engage more often. They each get a chance to detect but others are likely to reinforce any battle once engaged.

 

[Vidkjaer]

This fits what I have been seeing with subs in 1.2.0

A small fleet of uboats (5-10) will still mangle an unescorted convoy now. The small wolfpack if engaged by enemy boats actually lsoes fewer subs (is more eager to disengage quickly). These two points combined with your calculations on detection clearly imply that one should not deploy subs in packs of 30-40. One should spread then in packs of 15 or so even if this means that many will not have commanders.

Mulitple packs in the same zone will engage more often. They each get a chance to detect but others are likely to reinforce any battle once engaged.

And this doesnt make sence to me. It seems that the number of subs is not important to their detection chance. Their detection chance goes down if you use them in 2 or 3 naval region (according to my understanding of it).
The only reason you would want to use more than one naval region is your small numbers of naval commanders.
I love to hear the DEV's explain the naval mechanis in detail. It is a black box for me at the momement.

 

[sterrius]

i recommend fleets of 5 subs. They are enough to take down 1-3 convoys and if found they will not be missed. (well, they will but its cheap ).

to hunt, 5 destroyers are enough. Even fi they die they will kill more subs.