"Navigable River" Code

[mind_messing]

As per section 4.2.1.4 of the manual, navigable rivers:

Navigable rivers are rivers that ships may “sail” along. In map terms, they are river hexsides
that naval TFs can move across. Navigable rivers have the following effects and limitations:
»» Only ships with tonnages of 15,000 tons or less may cross navigable river hexsides.
»» The hexsides have effects on naval units that are similar to narrow straits – TFs crossing them are more vulnerable to mines and any CD units that are present.
»» TFs will not react along a river unless the range to the enemy is one hex.

For ground units, navigable rivers act in the same way as any other river.

The issue is highlighted in bold - CD fire does not seem to occur on navigable rivers at all. I've tested having a convoy of 30 xAK's sail up and down the Yangste past CD guns in night and day, no CD gunfire occurs. A couple hit naval mines.

DL was a non-issue, as the convoy was well exposed to both day and night search.

A quick search of the forum shows that this has occurred elsewhere.

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Anything going on under the hood that isn't as it should be?

[Yaab]

I think you would have to define them as "narrow straits", and not just river hexsides, just like in the case of Bataan. Only then the CD guns seem to work. So put a CD unit on Yangtze in one hex and define the hexes as a strait.

[mind_messing]

ORIGINAL: Yaab

I think you would have to define them as "narrow straits", and not just river hexsides, just like in the case of Bataan. Only then the CD guns seem to work. So put a CD unit on Yangtze in one hex and define the hexes as a strait.

Straits code regarding CD gunfire works. River code doesn't.

[mind_messing]

I've been mucking around with this some more, and there's not been any way that I can find whereby I get CD guns to engage river traffic. They do fine when enemy ships attempt to sweep mines or conduct a naval invasion, but otherwise I can't get them to fire.

I've been using the Yangste as a baseline, is it possibly a pwhex issue?

[Yaab]

I damaged a RN ship past Shangai when she hit a mine on the Yangtse in RHS, so the Yangstse river hexes work fine re mines.

[Lokasenna]

ORIGINAL: Yaab

I damaged a RN ship past Shangai when she hit a mine on the Yangtse in RHS, so the Yangstse river hexes work fine re mines.

Well, what's "fine"? Is it "as well as any other hex", or are they in fact more vulnerable to mines in rivers? It's not really possible for us to tell.



Changing the pwhex data for the rivers to change them to narrow straits, from river, would remove the restriction on large ships moving upriver, would it not?

[witpqs]

ORIGINAL: Lokasenna

ORIGINAL: Yaab

I damaged a RN ship past Shangai when she hit a mine on the Yangtse in RHS, so the Yangstse river hexes work fine re mines.

Well, what's "fine"? Is it "as well as any other hex", or are they in fact more vulnerable to mines in rivers? It's not really possible for us to tell.



Changing the pwhex data for the rivers to change them to narrow straits, from river, would remove the restriction on large ships moving upriver, would it not?

Not sure about that, I thought it was the hex-side code that prevented/allowed certain sizes to pass, but I have never messed around with that and learned the ins and outs of it.

[Yaab]

ORIGINAL: Lokasenna

ORIGINAL: Yaab

I damaged a RN ship past Shangai when she hit a mine on the Yangtse in RHS, so the Yangstse river hexes work fine re mines.

Well, what's "fine"? Is it "as well as any other hex", or are they in fact more vulnerable to mines in rivers? It's not really possible for us to tell.



Changing the pwhex data for the rivers to change them to narrow straits, from river, would remove the restriction on large ships moving upriver, would it not?

"Fine" in the sense that mines placed in river hexes work and can damage or sink ships.

[Lokasenna]

ORIGINAL: witpqs

ORIGINAL: Lokasenna

ORIGINAL: Yaab

I damaged a RN ship past Shangai when she hit a mine on the Yangtse in RHS, so the Yangstse river hexes work fine re mines.

Well, what's "fine"? Is it "as well as any other hex", or are they in fact more vulnerable to mines in rivers? It's not really possible for us to tell.



Changing the pwhex data for the rivers to change them to narrow straits, from river, would remove the restriction on large ships moving upriver, would it not?

Not sure about that, I thought it was the hex-side code that prevented/allowed certain sizes to pass, but I have never messed around with that and learned the ins and outs of it.

Right, and aren't straits done the same way? Are they mutually exclusive (i.e., a hex side only has one type and can't have multiples)?

[Yaab]

Frankly, this I do not know. You would have to check the manual and Modding forum.

[LargeSlowTarget]

"River" and "Straits" are two separate values so in theory not mutually exclusive. Have not tested the river CD units yet, so no idea if it works in practise.

[witpqs]

ORIGINAL: LargeSlowTarget

"River" and "Straits" are two separate values so in theory not mutually exclusive. Have not tested the river CD units yet, so no idea if it works in practise.

So I notice on that display that there are 'river' and 'strait' parameters for each hex side, and also for the hex. In that graphic they are set to 'none' for the hex itself. As I mentioned I don't have any experience messing around with these parameters, but I wonder how the hex side versus hex river/strait parameters interact with each other in the code?

[LargeSlowTarget]

In the hex editor I cannot find any hex for which the "hex interior" parameters contains anything else than "none" for "River size" and "Strait type" - therefore I believe only the hexside parameters do count.

I did some limited testing this weekend with Chinese "Jangtze Gorges" CD units I have created in a mod. I have set the hexsides to "navigable river" with "narrow straits" and then experimented with hexagon type set to "land" as well as to "coastal" (and made sure the guns in the CD units are "naval gun" devices and not "Army weapon"). The CD units did fire back at a bombardment TF of river gunboats, but left a surface TF and landing craft TF passing through the hex alone. I have also made a test with the Singapore hex, which does have working CD guns (don't ask how I have found out...) and a navigable river hexside to the NE (Johore Baru). I have set-up a Japanese bombardment TF and a surface TF to move from Johore through the river hexside to Singers. Well, the bombarment TF never had a chance to get fired on as all its ships hit mines. The surface TF survived the minefield and was NOT engaged by the CD units. So my impression is that indeed CD units do not interdict river traffic - straits or no straits.

[mind_messing]

ORIGINAL: LargeSlowTarget

In the hex editor I cannot find any hex for which the "hex interior" parameters contains anything else than "none" for "River size" and "Strait type" - therefore I believe only the hexside parameters do count.

I did some limited testing this weekend with Chinese "Jangtze Gorges" CD units I have created in a mod. I have set the hexsides to "navigable river" with "narrow straits" and then experimented with hexagon type set to "land" as well as to "coastal" (and made sure the guns in the CD units are "naval gun" devices and not "Army weapon"). The CD units did fire back at a bombardment TF of river gunboats, but left a surface TF and landing craft TF passing through the hex alone. I have also made a test with the Singapore hex, which does have working CD guns (don't ask how I have found out...) and a navigable river hexside to the NE (Johore Baru). I have set-up a Japanese bombardment TF and a surface TF to move from Johore through the river hexside to Singers. Well, the bombarment TF never had a chance to get fired on as all its ships hit mines. The surface TF survived the minefield and was NOT engaged by the CD units. So my impression is that indeed CD units do not interdict river traffic - straits or no straits.

I think that's the nail in the coffin that rivers are not working as mentioned in the manual.

[PaxMondo]

Maybe,

All I will add here is that CD units have a 'chance' to engage, and that chance depends on a bunch of 'things' never fully disclosed except that the perception of the relative strength. So, instead of trying 40 xAK's or whatever, I would suggest a few (couple?) xAKL's instead ... and make sure full moon ... and maybe put 4 CD units there with good commanders with high aggression .... and good DL and ...

I've sailed through the Singers straight several times (plot mistakes) and not have the shore batteries engage ... but they do engage other times ...

anyway ... just a couple of thoughts. it wouldn't surprise me that river CD's are not working, but then again, testing is so difficult when you don't know all of hte variables ...

[PaxMondo]

I would add that CD's do work just fine against amphib assault on the rivers ......

[LargeSlowTarget]

I made more test with Singers. This time I have set the mines to effect = 1 and sent a couple of minesweepers as well.

Test 1 : All TFs coming down from Johore through river hex side set to remain on station at Singers. Results : The minesweepers swept a few mines but quickly got sunk by CD guns, the bombardment TF was engaged by CD guns and suffered moderate damage, the surface TF again stayed in the Singers hex all day long without being molested (apart from a couple of mine hits which with effect = 1 only scratched some paint).

Test 2: All TFs coming down from Johore through river hex side set to retire towards CRB (exiting through an ocean hex side obviously). Results : minesweepers sunk by CD, bombardment TF engaged by CD, surface TF engaged by CD as well - maybe due to leaving through the ocean hex side towards CRB ?

When I find the time, I will re-run the tests several times to see if there are consistent or random results.

Not saying my test are conclusive, they are just reinforcing an impression.

[BBfanboy]

The hex is 40 NM wide so at minimum there are 20 NM of water between CD unit location and hex side for the SCTF to operate in. If the SCTF stays out near the hex edge, the CD unit does not engage. If it comes in close enough the CD unit may engage. The AI uses "under-the-hood" randoms to determine positioning and engagement or not.

Mines work much the same - most are laid close to shore so if a TF passes through the hex well away from the base, it is unlikely to hit one. Bombardment TFs moving close (6000') to shore might hit one. Amphib TFs moving up to the shore will find them.

[mind_messing]

ORIGINAL: LargeSlowTarget

I made more test with Singers. This time I have set the mines to effect = 1 and sent a couple of minesweepers as well.

Test 1 : All TFs coming down from Johore through river hex side set to remain on station at Singers. Results : The minesweepers swept a few mines but quickly got sunk by CD guns, the bombardment TF was engaged by CD guns and suffered moderate damage, the surface TF again stayed in the Singers hex all day long without being molested (apart from a couple of mine hits which with effect = 1 only scratched some paint).

Test 2: All TFs coming down from Johore through river hex side set to retire towards CRB (exiting through an ocean hex side obviously). Results : minesweepers sunk by CD, bombardment TF engaged by CD, surface TF engaged by CD as well - maybe due to leaving through the ocean hex side towards CRB ?

When I find the time, I will re-run the tests several times to see if there are consistent or random results.

Not saying my test are conclusive, they are just reinforcing an impression.

Singers is a bad testbed, as the strait code isn't what we're concerned about here. Pick a major river. I used the Yangste, but you can use the one at Palembang, or that one in the Soviet Far East (but that might be a strait as well).

[LargeSlowTarget]

Singers has a navigable river hex side to the NE towards Johore Baru, and this is the hex side used in my test. IRL Johore Strait between the two locations is an inlet- but in the game it is considered as a river. So I don't agree that this is a bad testbed.