Minesweeping

[Chris21wen]

I read something yesterday on the forum on minesweeping, problem is I cannot find it now so I may have stumbled on something old thinking it was new. Whatever, it made be re-evaluate minesweeping. Alfred wrote a piece 5 years ago on minesweeping but having read it, it's not how it's working now.

The majority of what he wrote is still valid but patches have changed things, I've simplified it here but you can read his full test here https://www.matrixgames.com/forums/view ... 6&start=20

1. Minesweepers need to be in a TF to sweep AND undocked if it's their own base they are sweeping.
2. There are four types of minesweeper, AM, DMS, YMS, and AMc. The first two can sweep there own hex plus any adjacent hex, the later two only their own hex and are limited to local MSW, escort and support TF.
3. There are two types of sweep, a full minefield sweep and a channel/transit sweep.
4. Only minesweepers can carry out a full sweep. The number of ships is limited to 4.
5. Other TF types can have a minesweeper in them but they will only carry out a channel/transit sweep. The numbers appear unlimited.
6. Escorts in any type of TF will also destroy mines but they are not sweeping and are more prone to mine damage.
7. Sweep operations are nearly always carried out at the destination hex but can also occur in any hex, even the open ocean but it's as rare as hens teeth.
8. To carry out a full sweep the minesweeper TF needs to be set to 'Remain on Station'.
9. Setting it or any TF with a minesweeper to 'Retirement allowed' results in a channel/transit sweep, returning to base once there mission is complete.
10. Channel/transit sweeps only occur on the turn they arrive at their destination. Minesweepers will do nothing on subsequent turns unless you move them to a minesweeping TF.
11. It is possible a channel/transit sweep will clear a minefield but generaly they only clear a few mines. I repeat what I said earlier, Only a minesweeping TF will sweep a field.
12. Local MSW TFs tend to route around other minefields. Setting them to direct over comes this. This is not a promlem with MSW TF. This isn't a leader thing but may have something to do with speed?
13. If you want to sweep a home port the minesweeping TF need to be UNDOCKED.

[JanSako]

I wanted to ask if anyone actually seen a DMS or AM sweep a neighboring hex. It just feel weird, notwithstanding that one could, i.e. as IJN just sweep the minefields from outside Soerabaja & then go in & bombard with impunity. Same as USN, just park the minesweeper TF outside their base, the Death Star right next to it for cover & once the mines are gone, send in the heavies.

The 'Undock' for base sweeping is logical, it makes the ship consume fuel, similar to an ACM when maintaining own fields.
Sweeping for enemy mines means the ship actually needs to leave the harbor & its approaches.

[Trugrit]

You don’t want Remain on Station to be set

With Remain on station the Minesweeper FT will stay in the set Hex.

You want a single Patrol zone set in the Hex. With that the FF
will sweep the Hex then move through the surrounding 6 Hexes
and search.

I never set remain on Station; I always a 1 Hex Patrol Zone.
Sometimes a Two Hex if I want to sweep in and out.

Below….Minesweeping TF 8 has a 1 Hex patrol zone set at Iwo Jima.
It will sweep the Hex then travel around the 6 surrounding Hexes and
Clear the Japanese mines set adjacent.

They will sweep both Morning and afternoon Phases.

Iwo.jpg (144.24 KiB) Viewed 1578 times

You can get a better look at this if you watch the replay.

Clear.jpg (103.04 KiB) Viewed 1578 times

[RangerJoe]

IF there is a type of IJN minesweeper in the hex, then Japanese PBs can be in a minesweeping TF. The Ansyu C PB can usually take a mine hit and survive, but not always. They do sweep slower than regular minesweepers but they are less likey to be lost.

Also, the AMc minesweepers don't have to be in a TF to function, they are supposed to be able to do the job while disbanded in a port.

[Chris21wen]

The 'Undock' for base sweeping is logical, it makes the ship consume fuel, similar to an ACM when maintaining own fields.
Sweeping for enemy mines means the ship actually needs to leave the harbor & its approaches.

ACM do not have to be in a TF to maintain a field. They will do it in port.

I wanted to ask if anyone actually seen a DMS or AM sweep a neighboring hex. It just feel weird, notwithstanding that one could, i.e. as IJN just sweep the minefields from outside Soerabaja & then go in & bombard with impunity. Same as USN, just park the minesweeper TF outside their base, the Death Star right next to it for cover & once the mines are gone, send in the heavies.

Yes they will, here's the proof. Created a 2x DMS undocked in in Singora. There do have a tendancy to start in their own hex but will usually alternate thereafter. Once their hex is clear they will then concentrate on adjacent hexes. I never tried with mines in more than two adjacent hexes but suspect it's just a variation.

I did note two things that I did not mention before.
The option to minesweep occurs every movement phase so you can get upto three sweeps per turn.
If you can see the minefield being sweeped during the execution phase the mines sometimes gets brighter!

AFTER ACTION REPORTS FOR Dec 22, 41
--------------------------------------------------------------------------------
TF 1 encounters mine field at Singora (51,72)

Japanese Ships
DMS W-6
DMS W-5

4 mines cleared


--------------------------------------------------------------------------------
TF 1 encounters mine field at Patani (51,73)

Japanese Ships
DMS W-6
DMS W-5

11 mines cleared


--------------------------------------------------------------------------------
TF 1 encounters mine field at Singora (51,72)

Japanese Ships
DMS W-6
DMS W-5

10 mines cleared

[JanSako]

Never said the ACM need to be in a TF, just that they do use fuel to maintain the mines. Just sitting in port they do which is unique behavior.

When AM's sweep mines in adjacent hexes, does the TF actually go to the hex or they do it from 40 miles away using astral projection? If the former, that's OK because at least they will get smacked around by CD guns, if there are any. If they do not actually enter the (neighbor) hex, yet they sweep the mines, I would like to hear the reasoning before a new house rule is born .

[Chris21wen]

Never said the ACM need to be in a TF, just that they do use fuel to maintain the mines. Just sitting in port they do which is unique behavior.

When AM's sweep mines in adjacent hexes, does the TF actually go to the hex or they do it from 40 miles away using astral projection? If the former, that's OK because at least they will get smacked around by CD guns, if there are any. If they do not actually enter the (neighbor) hex, yet they sweep the mines, I would like to hear the reasoning before a new house rule is born .

They never move from their hex. I look up it as a minesweeping patrol area covering 7 hexes more than a magic 'astral projection'. Perfectly reasonable I think.

I've since set up another test where there was more than one adjacent minefield but I rarely saw more than two hexes being sweeped in any turn, sometimes just one. Other observations are; adjacent hexes tended to have fewer mines sweeped per turn and sweeping ocurred in this order of preference, own base, other bases then open sea.

In the case below a 4x DMS TF was based at Singora. It clear Singora first , then Patani followed by the two sea hexes taking seven days to clear approx 400 mines. I ran it three times with same results.

Capture.JPG (12.92 KiB) Viewed 1493 times

[Chris21wen]

You don’t want Remain on Station to be set

With Remain on station the Minesweeper FT will stay in the set Hex.

You want a single Patrol zone set in the Hex. With that the FF
will sweep the Hex then move through the surrounding 6 Hexes
and search.

I never set remain on Station; I always a 1 Hex Patrol Zone.
Sometimes a Two Hex if I want to sweep in and out.

Below….Minesweeping TF 8 has a 1 Hex patrol zone set at Iwo Jima.
It will sweep the Hex then travel around the 6 surrounding Hexes and
Clear the Japanese mines set adjacent.

Hadn't carried out any tests on minesweeping with patrol zones but now I have. Alfred said somewhere that minesweeping with patrols is not needed and after the test I carried out I agree. It's my belief that the minesweeping algoritum has an inbuilt patrol zone of 7 hexes in and around it's destination hex.

A patrol was set up near Patani with three patrol points using 2xAMc. Patani was always cleared first, when depended upon the first patrol point. The other points were sweeped as the patrol passed through sweeping far fewer mines per turn than Patani itself. To my mind it seem Patani had a full sweep while the patrol points only had a channel/transit sweep.

I also tested remain on station with the patrol and as you say the TF stays in the same hex. If you sweep without setting up a patrol, the normal sweep method, then remain on station has no effect.

All in all I would say setting a patrol up is not needed, just let the normal MSW TF do it's thing.

Capture.JPG (13.34 KiB) Viewed 1491 times

[Chris21wen]

IF there is a type of IJN minesweeper in the hex, then Japanese PBs can be in a minesweeping TF. The Ansyu C PB can usually take a mine hit and survive, but not always. They do sweep slower than regular minesweepers but they are less likey to be lost.

Also, the AMc minesweepers don't have to be in a TF to function, they are supposed to be able to do the job while disbanded in a port.

Escort ships can be put into a MSW TF but not a local MSW TF. I repeat my finding from earlier and as Alfred said escorts do not sweep mines only minesweepers activate the sweep algorithum. They will destroy mines but only a few and are likely to suffer casualties. It's dangerous for a sweeper let alone a none minesweepers. MSW TF is not a place for none minesweepers, the only possible reason for doing so is to draw fire from shore batteries.

If you are landing troops then after the initial first turn of landing and the sweepers have sweeped a channel then I'd assume it's resonable to place the sweepers in a minesweeping TF to sweep the field. Hopefully any shore batteries would be too occupied with the amphib landing to go after the sweepers but would leave them there if the Amphib TF withdraws.

Sorry they do not sweep in port, I don't remember a time when they did. You can try it if you like but in all the test I've carry out I saw nothing that suggests they do. ACM will however maintain fields in port.

[Trugrit]

You don’t want Remain on Station to be set

With Remain on station the Minesweeper FT will stay in the set Hex.

You want a single Patrol zone set in the Hex. With that the FF
will sweep the Hex then move through the surrounding 6 Hexes
and search.

I never set remain on Station; I always a 1 Hex Patrol Zone.
Sometimes a Two Hex if I want to sweep in and out.

Below….Minesweeping TF 8 has a 1 Hex patrol zone set at Iwo Jima.
It will sweep the Hex then travel around the 6 surrounding Hexes and
Clear the Japanese mines set adjacent.

Hadn't carried out any tests on minesweeping with patrol zones but now I have. Alfred said somewhere that minesweeping with patrols is not needed and after the test I carried out I agree. It's my belief that the minesweeping algoritum has an inbuilt patrol zone of 7 hexes in and around it's destination hex.

A patrol was set up near Patani with three patrol points using 2xAMc. Patani was always cleared first, when depended upon the first patrol point. The other points were sweeped as the patrol passed through sweeping far fewer mines per turn than Patani itself. To my mind it seem Patani had a full sweep while the patrol points only had a channel/transit sweep.

I also tested remain on station with the patrol and as you say the TF stays in the same hex. If you sweep without setting up a patrol, the normal sweep method, then remain on station has no effect.

All in all I would say setting a patrol up is not needed, just let the normal MSW TF do it's thing.Capture.JPG

I agree that that a single Hex Patrol zone is not needed but I use
the single Hex patrol zone extensively almost everywhere else.

I think it gives me more task force movement in the Hex which helps
to lower the task force detection level. That may just be my superstition,
but I go with it.

For Minesweeping I almost never set a multiple Hex patrol zone around
The port. I use a single Hex patrol zone.

Setting a multiple Hex patrol zone breaks the natural algorithm.

You are correct in you never want to use any non-mine type
ships to clear mines.

As for regular escort or non-minesweeper type ships here is a
purely academic exercise:

To set up the minesweeper algorithm you want a minesweeper to
be in the task force….usually I make it the first ship to go into the
task force then I add the regular escorts to it.

Then you can use a right mouse click to remove the minesweeper
(in the case below the Adroit) from the task force.

When you run it the regular destroyers will perform the sweep.

This is something you never want to do. The regular ships will take forever
to clear a field and they are at much greater danger to hit a mine instead of
to clear one…..Academic exercise only.

As below…..three turns in and 5 regular destroyers have only cleared one mine.

Adroit 3.jpg (179.83 KiB) Viewed 1457 times

[JanSako]

Thank you for running all the tests!

If you are landing troops then after the initial first turn of landing and the sweepers have sweeped a channel then I'd assume it's resonable to place the sweepers in a minesweeping TF to sweep the field. Hopefully any shore batteries would be too occupied with the amphib landing to go after the sweepers but would leave them there if the Amphib TF withdraws.

What is the point to have the minesweeping TF even enter the hex with shore batteries if they can sweep using the astral projection? Just park the minesweeping TF outside enemy hex for a couple of days & sit back while they magically sweep the mines right in front of those shore batteries with 0 danger to themselves. Yes, they can get attacked by air or surface TF's but that is a whole different topic.

According to all evidence it seems to work this way, but in any future game of mine there will be a rule against it.

[JorMallester]

Thank you for running all the tests!

If you are landing troops then after the initial first turn of landing and the sweepers have sweeped a channel then I'd assume it's resonable to place the sweepers in a minesweeping TF to sweep the field. Hopefully any shore batteries would be too occupied with the amphib landing to go after the sweepers but would leave them there if the Amphib TF withdraws.

What is the point to have the minesweeping TF even enter the hex with shore batteries if they can sweep using the astral projection? Just park the minesweeping TF outside enemy hex for a couple of days & sit back while they magically sweep the mines right in front of those shore batteries with 0 danger to themselves. Yes, they can get attacked by air or surface TF's but that is a whole different topic.

According to all evidence it seems to work this way, but in any future game of mine there will be a rule against it.

This what I am interested in.

After reading through the tests carried out above, I believe it is mentioned that if sweeps are carried out the normal way (without patrol) remain on station has no effect. Therefore, could one simply set a destination hex next to the hex filled with mines, pop on remain on station, and wait for the potential sweep of the adjacent hex filled with mines?

I don't think I will ever run out of questions/thoughts on this game! Always interesting reading through this forum.

[BBfanboy]

The way I read Trugrit's posts, you don't put the TF in "Remain on Station" orders, you leave it with the one hex patrol zone. Patrol zones use the React settings while "Remain on Station" does not.

[Chris21wen]

What is the point to have the minesweeping TF even enter the hex with shore batteries if they can sweep using the astral projection? Just park the minesweeping TF outside enemy hex for a couple of days & sit back while they magically sweep the mines right in front of those shore batteries with 0 danger to themselves. Yes, they can get attacked by air or surface TF's but that is a whole different topic.

According to all evidence it seems to work this way, but in any future game of mine there will be a rule against it.

I never tested that, I assumed they did get attacked by shore batteries and now I know, they do. Using remain on station I parked MSW TFs next to Batan and Singas here's the result.

--------------------------------------------------------------------------------
TF 1 encounters mine field at Bataan (78,77) - Coastal Guns Fire Back!

10 Coastal gun shots fired in defense.

Japanese Ships
DMS W-12, Shell hits 6, heavy fires, heavy damage
DMS W-11, Shell hits 11, heavy fires, heavy damage
DMS W-10, Shell hits 3, heavy fires, heavy damage
DMS W-9, Shell hits 3, on fire, heavy damage

Manila Bay Defenses firing at DMS W-12
DMS W-12 firing at Manila Bay Defenses
Manila Bay Defenses firing at DMS W-11
Manila Bay Defenses firing at DMS W-10
DMS W-10 firing at Manila Bay Defenses
Manila Bay Defenses firing at DMS W-9
DMS W-9 firing at Manila Bay Defenses
41 mines cleared

AFTER ACTION REPORTS FOR Dec 18, 41
--------------------------------------------------------------------------------
TF 4 encounters mine field at Singapore (50,84) - Coastal Guns Fire Back!

39 Coastal gun shots fired in defense.

Japanese Ships
DMS W-5, Shell hits 8, heavy fires, heavy damage
DMS W-3, Shell hits 10, heavy fires, heavy damage
DMS W-2, Shell hits 3, heavy fires, heavy damage
DMS W-1, Shell hits 3, heavy fires, heavy damage

Singapore Fortress firing at DMS W-5
DMS W-5 firing at Singapore Fortress
Singapore Fortress firing at DMS W-3
DMS W-2 firing at Singapore Fortress
Singapore Fortress firing at DMS W-2
DMS W-1 firing at Singapore Fortress
Singapore Fortress firing at DMS W-1
20 mines cleared

[JanSako]

Excellent, thank you again for this!

The guns engaging it means the minesweeping TF is considered as entering the (neighboring) hex with the minefield, otherwise now we have the CD guns astral projecting shells at 40 miles

+1 to the earlier comment, one can always learn more about the game & it's mechanics!

The guns did score 23 hits out of 10 shots, but that is a smaller issue. I think the 'shot' is really a salvo & Manila Bay defenses can throw some pretty large ones.

[RangerJoe]

Excellent, thank you again for this!

The guns engaging it means the minesweeping TF is considered as entering the (neighboring) hex with the minefield, otherwise now we have the CD guns astral projecting shells at 40 miles

+1 to the earlier comment, one can always learn more about the game & it's mechanics!

The guns did score 23 hits out of 10 shots, but that is a smaller issue. I think the 'shot' is really a salvo & Manila Bay defenses can throw some pretty large ones.

Yes, those shots are salvos or multiple salvos. Look up the magazine capacity and then compare the number of shots per gun for the ship type in the game.

[Sardaukar]

Every ship can be a minesweeper...once...

[Yaab]

IF there is a type of IJN minesweeper in the hex, then Japanese PBs can be in a minesweeping TF. The Ansyu C PB can usually take a mine hit and survive, but not always. They do sweep slower than regular minesweepers but they are less likey to be lost.

Also, the AMc minesweepers don't have to be in a TF to function, they are supposed to be able to do the job while disbanded in a port.

AMc sweeping mines while being disbanded in port? Can anyone confirm it? I always create on-map TFs with them.

[Yaab]

I wanted to ask if anyone actually seen a DMS or AM sweep a neighboring hex. It just feel weird, notwithstanding that one could, i.e. as IJN just sweep the minefields from outside Soerabaja & then go in & bombard with impunity. Same as USN, just park the minesweeper TF outside their base, the Death Star right next to it for cover & once the mines are gone, send in the heavies.

The 'Undock' for base sweeping is logical, it makes the ship consume fuel, similar to an ACM when maintaining own fields.
Sweeping for enemy mines means the ship actually needs to leave the harbor & its approaches.

Start a new game as Allies, create an AM TF in Manila, set it to patrol Manila, and on the next turn, the TF will sweep Jap mines in Bataan hex.

[BBfanboy]

I wanted to ask if anyone actually seen a DMS or AM sweep a neighboring hex. It just feel weird, notwithstanding that one could, i.e. as IJN just sweep the minefields from outside Soerabaja & then go in & bombard with impunity. Same as USN, just park the minesweeper TF outside their base, the Death Star right next to it for cover & once the mines are gone, send in the heavies.

The 'Undock' for base sweeping is logical, it makes the ship consume fuel, similar to an ACM when maintaining own fields.
Sweeping for enemy mines means the ship actually needs to leave the harbor & its approaches.

Start a new game as Allies, create an AM TF in Manila, set it to patrol Manila, and on the next turn, the TF will sweep Jap mines in Bataan hex.

RJ contends only AMcs will auto-sweep from a disbanded start. I think it was Trugrit that showed that an AM minesweeping TF will sweep any adjoining hex if it detects enemy mines there.