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HOI4 Dev Diary - Mines and Minesweeping

Welcome to another glorious Wednesday! Today we are going to be talking about mines and mine sweeping. Historically hundreds of thousands of mines were laid during WW2 and with Man the Guns you too will be able to do so in Hearts of Iron.

From a gameplay perspective mines do a lot of interesting things. They add more interaction with the naval layer of the game, create a weapon both for smaller naval nations to fight bigger ones, and for big ones to try and limit where the enemy can get to them.

Screenshot_1.jpg


As you may remember from my presentation at PDXCON, I talked about adding a ship designer to Man the Guns. It is not quite ready to show off, but it’s important to know that sweeping and laying mines are something you will be upgrading or redesigning your ships to be doing. Minelayers and Minesweepers are not actually new ship classes. In my screenies I have destroyers that can both lay and sweep mines for simplicity, but as @Archangel85 pointed out earlier “I am probably going to have a ton of different destroyer designs”... anyways, details on the designer is for a future diary when it is done, but hopefully it helps explain some stuff in the proper context.

Mines are unlocked from techs and require ship designs fitted to deploy them. Destroyers and light cruisers can do this, as well as submarines with the correct tech (excellent if you as Germany want to make things even more dangerous for the British at a lower risk to yourself). Mines can also be dropped from the air with later game techs. Both of these unlock new missions for navies and airwings.
mine_techs.jpg


Mines can be made better and better through research. You start off with Contact Mines to unlock them. Then their destructive power is improved with Magnetic and Acoustic mine techs and finally with Pressure mines. At the bottom (heh) you also see two techs for submarine mine laying. The first is just the basic ability, while the second improves efficiency a lot by allowing mines to be deployed through torpedo tubes, thus no longer requiring you to design specialized minelaying submarines.

To get rid of mines you need minesweeper capable ships. This unlocks the naval mission to sweep mines and will slowly work at clearing areas. Minesweepers are also nice to include in your fleets as they will then be assumed to travel ahead of the fleet and reduce the impact of mines on them. I suspect a good design combo will be anti-air and sweeper on screen ships to be your passive defense when in enemy waters.
mine_report_map.jpg


There is also a passive “degaussing” technology that can be researched after Magnetic Mines. This was employed during WW2 to reduce the magnetic signature of ships and thus make them less likely to set off mines.

It is also possible to sweep mines from the air, but this is a late game, expensive technology and unlocks a new air mission for bombers. This was something that was done sparingly and in shallow waters, but for example was successfully done to evacuate the Dutch royal family to Britain.

What do mines exactly do then? Well they blow stuff up! Their explosive results are shown on map as accident reports, and there is a new tab too under the Naval Losses statistics interface if you want to dig into details. As ships operate or move through a zone they will risk running into mines. This can lead both to minor damage as well as outright sinkings. The best ways to avoid this is to make sure the area is swept free of mines, but as mentioned above, having your ships travel with sweeping capable ships makes it safer for all.

mines report.jpg

This is not all through, mines have several passive effects.

Naval superiority - Having mines in an area helps amplify the effects of your navy (after all they can concentrate more effectively knowing where the mine fields are). This can be seen in our new naval area screen, which is the naval equivalent of the state view:
travel.jpg


Other than that and blowing ships up mines will slow down enemy ships (since they need to be more careful) and increases the invasion penalty to coastal area. So mines are both good offensively and defensively.

rep2.jpg


Mines can only be laid while at war and will start to disappear over time once a nation is completely at peace. You always know how much mines there are in an area, so you know how to deal with them and take them into account. That means that with the new naval access controls you can tell your ships and convoys to avoid heavily mined areas, but of course this may make it a lot more predictable for your enemies where to hunt. Having an advantage in the encryption-decryption war will also add a certain amount of passive defense against mine effects as you may have some information about their positioning.

See you all next week for more Man the Guns info!

Rejected Titles (for extra good reason this time...):
- This War of Mine
- Vengeance is Mine sayeth the Lord Admiral
- Do you mine’d
- This feature was made in cooperation with the seagulls from Finding Nemo
- Mine = blown
- The Ship Designer isn’t unfinished, it’s just a bit shy
- Minesweeper 2000 Online HD Edition
- Mine over Matter
- Mine the guns
 
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So ships can also be sunk in training through accidents not caused by mines?

well, we are kinda playign with that. right now they get taken to 1% damage and dont die. because its annoying when training to lose a ship to bad luck. but we may make exceptions for war time or say mined areas. ask me in the future where we landed ;)

Will we be seeing land mines in the future? They were also an important part of the war.

no plans for it, but mostly because I think the scales is a bit small and I havent given it much thought.. so who knows, maybe if we get a good idea
 
IIRC, landmines weren't necessarily used to kill people, more to guide them into predesignated killzones, and as such are already represented by the combat bonuses that landforts give you.
 
yea. there is gonna be some tweaks. we have also done other changes to research we will be showing in the future
Will mining efficiency be dependent on range? Putting 200k naval mines along the northern European coast as Germany is completely different than doing the same off the US Eastern seaboard.
 
In WWII, how many warships were sunk by mines?
not sure on count, here is a wiki link: https://en.wikipedia.org/wiki/Category:Ships_sunk_by_mines

When a sea area is swept by a mine sweeper well all the mines disappear or is a percentage based on the tech level you have.

Also a question. Well the number of mines laid and it’s destructive power depend on the size of the sea area? I guess I’m wondering how that well work.
- sweeping works just like laying mines, so you slowly reduce them. not all at once
- atm "size on map" isnt a factor, but there are other things that play in here. see a future diary when we go over "naval terrain"
 
Mines can only be laid while at war and will just go away once a nation is completely at peace. You always know how much mines there are in an area, so you know how to deal with them and take them into account. That means that with the new naval access controls you can tell your ships and convoys to avoid heavily mined areas, but of course this may make it a lot more predictable for your enemies where to hunt. Having an advantage in the encryption-decryption war will also add a certain amount of passive defense against mine effects as you may have some information about their positioning.

See you all next week for more Man the Guns info!

Rejected Titles (for extra good reason this time...):
- This War of Mine
- Vengeance is Mine sayeth the Lord Admiral
- Do you mine’d
- This feature was made in cooperation with the seagulls from Finding Nemo
- Mine = blown
- The Ship Designer isn’t unfinished, it’s just a bit shy
- Minesweeper 2000 Online HD Edition
- Mine over Matter
- Mine the guns

I am totally getting a flashback of Benedict Cumberbatch in "The Imitation Game" talking about not use all of the info they have to kept their capacity for engima breaking tech a secret from Nazi Germany.
 
Something I wanted to ask, although perhaps the new ship designer system will kind of answer this as a "yes"; will the 1922 tech ships - which represent everything from ~1890 to the 1930s - be updated in some way to reflect the huge variety in their actual states? To use a single example of battleships, the two German pre-dreadnoughts from 1904 (obsolete when WW1 started) and the British Revenge-class battleships are identical in game. There are numerous problems with this, and it's only one of many examples, but I just wondered whether ship techs/classes are getting a sort of QA pass in MtG?

Also, France starts (uniquely) with a 1940 ship tech, because currently there is no sensible way to represent their Dunkerque-class ships.
 
Will mines be layable via command for us modders? It would be great for us to be able to have mine-laying events or decisions!
 
I am totally getting a flashback of Benedict Cumberbatch in "The Imitation Game" talking about not use all of the info they have to kept their capacity for engima breaking tech a secret from Nazi Germany.
future dlc in my dreams....
 
Welcome to another glorious Wednesday! Today we are going to be talking about mines and mine sweeping. Historically hundreds of thousands of mines were laid during WW2 and with Man the Guns you too will be able to do so in Hearts of Iron.

From a gameplay perspective mines do a lot of interesting things. They add more interaction with the naval layer of the game, create a weapon both for smaller naval nations to fight bigger ones, and for big ones to try and limit where the enemy can get to them.

View attachment 399112

As you may remember from my presentation at PDXCON, I talked about adding a ship designer to Man the Guns. It is not quite ready to show off, but it’s important to know that sweeping and laying mines are something you will be upgrading or redesigning your ships to be doing. Minelayers and Minesweepers are not actually new ship classes. In my screenies I have destroyers that can both lay and sweep mines for simplicity, but as @Archangel85 pointed out earlier “I am probably going to have a ton of different destroyer designs”... anyways, details on the designer is for a future diary when it is done, but hopefully it helps explain some stuff in the proper context.

Mines are unlocked from techs and require ship designs fitted to deploy them. Destroyers and light cruisers can do this, as well as submarines with the correct tech (excellent if you as Germany want to make things even more dangerous for the British at a lower risk to yourself). Mines can also be dropped from the air with later game techs. Both of these unlock new missions for navies and airwings.
View attachment 399109

Mines can be made better and better through research. You start off with Contact Mines to unlock them. Then their destructive power is improved with Magnetic and Acoustic mine techs and finally with Pressure mines. At the bottom (heh) you also see two techs for submarine mine laying. The first is just the basic ability, while the second improves efficiency a lot by allowing mines to be deployed through torpedo tubes, thus no longer requiring you to design specialized minelaying submarines.

To get rid of mines you need minesweeper capable ships. This unlocks the naval mission to sweep mines and will slowly work at clearing areas. Minesweepers are also nice to include in your fleets as they will then be assumed to travel ahead of the fleet and reduce the impact of mines on them. I suspect a good design combo will be anti-air and sweeper on screen ships to be your passive defense when in enemy waters.
View attachment 399110

There is also a passive “degaussing” technology that can be researched after Magnetic Mines. This was employed during WW2 to reduce the magnetic signature of ships and thus make them less likely to set off mines.

It is also possible to sweep mines from the air, but this is a late game, expensive technology and unlocks a new air mission for bombers. This was something that was done sparingly and in shallow waters, but for example was successfully done to evacuate the Dutch royal family to Britain.

What do mines exactly do then? Well they blow stuff up! Their explosive results are shown on map as accident reports, and there is a new tab too under the Naval Losses statistics interface if you want to dig into details. As ships operate or move through a zone they will risk running into mines. This can lead both to minor damage as well as outright sinkings. The best ways to avoid this is to make sure the area is swept free of mines, but as mentioned above, having your ships travel with sweeping capable ships makes it safer for all.

View attachment 399108
This is not all through, mines have several passive effects.

Naval superiority - Having mines in an area helps amplify the effects of your navy (after all they can concentrate more effectively knowing where the mine fields are). This can be seen in our new naval area screen, which is the naval equivalent of the state view:
View attachment 399113

Other than that and blowing ships up mines will slow down enemy ships (since they need to be more careful) and increases the invasion penalty to coastal area. So mines are both good offensively and defensively.

View attachment 399114

Mines can only be laid while at war and will just go away once a nation is completely at peace. You always know how much mines there are in an area, so you know how to deal with them and take them into account. That means that with the new naval access controls you can tell your ships and convoys to avoid heavily mined areas, but of course this may make it a lot more predictable for your enemies where to hunt. Having an advantage in the encryption-decryption war will also add a certain amount of passive defense against mine effects as you may have some information about their positioning.

See you all next week for more Man the Guns info!

Rejected Titles (for extra good reason this time...):
- This War of Mine
- Vengeance is Mine sayeth the Lord Admiral
- Do you mine’d
- This feature was made in cooperation with the seagulls from Finding Nemo
- Mine = blown
- The Ship Designer isn’t unfinished, it’s just a bit shy
- Minesweeper 2000 Online HD Edition
- Mine over Matter
- Mine the guns
Cool, can't wait to put mine hands on those babies.

But an issue I brought up in the other thread is how all these new techs added since release and our research is still the same.
Any plans on addressing that? I can see MtG standing out, with so many possibilities for navies, a lot of new techs being added, which is great mind you, but will create a problem as time goes on.

Edit: nevermind, I was reading the DD while someone else already asked the same and the answer.
 
Is mine laying tied to shallow water, or can you place mines in all naval terrains?
 
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Not sure if this will improve gameplay or just feel like a chore.

Example: you set a mission for your task force and set "avoid" on heavily mined regions.
Few weeks later the enemy mines a previously unmined traversal region. A region that your task force will only pass from and to port, thus the mine layer is unhindered.
Your fleet will suffer badly next time it returns to port and back.

--> you'll frequently have to check for mines and fiddle with the route.

I can see the benefits of course. I only question if mines are better abstracted. Were the historical mine laying strategies different enough to be worth simulating?
 
IIRC, landmines weren't necessarily used to kill people, more to guide them into predesignated killzones, and as such are already represented by the combat bonuses that landforts give you.
So, if landmines are introduced they should just increase fort defense and/or entrenchment cap?
 
What happens between wars, in the case when Axis is destroyed and the SU declares against the Allies. Usually this happens pretty quick, and mines were an issue for countries for many years after the war. Having them just disappear seems wrong.

Best solution would be if the numbers in mined areas reduce over time naturally (weather, malfunctions and sharks eating them) with hastened reduction in times of peace. Then it would be great if it uses equipment.
That is a natural diminishing return because if you mine the whole world you have more areas that you need to restock a little every now and then.