No, that's not it.

In sh3 the wave influence seems to gradually lessen. In sh4 it just stops below the surface. The difference is dramatic.

I've tried changing many factors to improve it, but it seems to be a hard coded thing.

Btw, in SHCE it worked quite well too. I remember if you had to make a high speed sprint underwater, in rough seas, in SHCE you had to go down to 90 or 100 ft. move fast, then come up to p/s depth to make an observation. Of course, SHCE was a simpler game; there were only 3 sea-states; but at least they got them right.

I hadn't thought to try this. Sometime I'll give it a go.

Yes, that is the part I forgot.

I played around with the sleep coefficient and a few of the others. I can't make the men sleep more, but I can make the sleep more refreshing (if that is helpful). I could make the 'maintenance' duty reduce fatigue like sleep, but there is a drawback, as they will get to the point of having negative fatigue, if left in there too long. I'll have to think about this. I would like to give the player the option of being able to rest a few of the men, even while at GQ. This could be helpful in a long engagement. I guess it is a minor point, though.

There have been comments recently to the effect that ISP, and other physics mods are harmful to convoy integrity. I decided to test this notion, and see if there is anything to be learned.



First, I created a mission for the purpose. I put together a 12 ship merchant convoy. The convoy 'leader' is a large minelayer (not actually a merchant), the other 11 are an assortment. No real small or large ships. The biggest is a large old liner. I put a lot of 'old' ships in it, the idea being these might have more trouble keeping up. All the merchants have novice crews, all the DD's normal crews.

Additionally, there are 4 escorts, one ahead, one on either beam, and one astern. The rear escort is a small minesweeper, all the others are DD's.

The arrangement is 3 columns of 4 ships. There is about 500 yds. in between ships in a column, and about 1,000 yds. between columns. The escorts were placed about 3,000 yds. outside the convoy, but wonder around a lot, so I'm not sure it matters where we place them.

I had them follow a large rectangle, but instead of having them make 90° turns at the corners, I used two 45° turns spaced about 5 nm apart. I have doubts as to their ability to make sharp, or frequent turns. The weather is a little choppy, with 6 m/s wind. The mission starts at 0800.



Test #1

The date is Nov. 7, 1941, so the USN and IJN are still on speaking terms. I am using RFB and RSRDC with the required patches. I believe that these mods use 'stock' physics, and you would get the same results in stock, but I wanted to make sure the ships were the same.

The convoy starts out in good order and apart from one of the DD's almost smacking into me, not much happens. I do notice the Wakatake and Matsuki DD's look somewhat unstable, rolling more than they should. Could be a problem in heavy weather.

I use 32x TC for most of the time, going to 1x to examine the ships from time to time. In the turns, I notice they use an odd technique. One ship, the medium old comp. fr. looses it's place twice, not clear why. It then tags along, at the rear of the column, until eventually finding it's way back to it's proper place.

In spite of these minor issues, the convoy ships keep station pretty well. I can't follow them after dark very well, but when I spot them again, they look to be in good formation. My boat actually collides with one in TC, and makes a lot of nasty racket. I threw engines in reverse and the merchant gets back to the convoy. We have no damage and apparently they don't either.



Test #2

Same set up as above. In this one I pull ahead out of sight, submerge and ambush convoy with a salvo of 4 torpedoes. This with auto-targeting. Range was about 8,000 yds. and I used 1/2° offset angle. I aim at two ships in the far column, from long range (i.e. low speed). One of the first two hit, the others miss. The convoy looks disordered for a while, but goes on, intact. The one ship sinks.

After a short time, I fire another volley of 4, at two other ships. Two ships are hit (1 hit apiece), but not the ones I targeted. One sinks quickly, the other struggles on for 30 min. or so, before it too, sinks. The convoy stayed together.

The oddest part was how little the DD's attempted to interfere. One DD (at front) worked it's way back through the convoy, as if it was trying to locate a sub inside the convoy. However, there were no ship collisions. I couldn't follow the evasions of the individual ships, but it was obvious they detected the torps and attempted to evade.



Tomorrow, I'll repeat the tests with ISP.

Test #3

This is like #1, but with ISP.

For the most part, the convoy is ok. The Wakatake DD goes back into the convoy, tries to move in between ships in the middle column, it doesn't time the move well, and has to back to keep from hitting. This happened twice, until finally at the rear of the convoy it turns into the space between the next 2 columns.

One ship, the med. old comp. freighter looses it's place at the second turn. It seems like ships have a chance to 'loose their place' at a turn. When they do they meander around, and will usually get back sooner or later. This happened without ISP as well.



Test #4

Same as test #3.

Here I make a long range torpedo attack, like in #2.

1 torp hits and convoy is highly disrupted. Ship sinks. It seemed still shaky after 1 hr. and was almost back in good order after 1.5 hrs.




Test #5

Using only RFB and RSRDC.

I start submerged and ambush convoy with 4 torps.

I target minelayer (which is convoy leader). Two hit and it sinks promptly. Convoy is very disordered. After 1/2 hr. it looks better, but one ship is far outside convoy. After 2 hrs., it is in a good state, but one ship still not in the right place. There seems to be a certain individual factor involved. Some ships seem to become 'confused' either in a turn or in an attack.





Test #6

Same as #5, but with ISP.

Of 4 torps, one hits and sinks minelayer.

There is much disruption, but convoy is more or less reformed after 1/2 hr. The large old passenger is way out in front about 3,000 yds. At first I thought this was just panic or bad seamanship. On closer examination, I realize the Hog Island is in it's place. It seems that places can change after an attack and two ships will be jockeying for a position in convoy. This may be a bug in AI. No way to know for sure. Overall, the convoy recovered well, within a half hour.

Conclusions:

In normal operation (no attack), I don't see any difference with ISP and 'normal' mods. Certainly, either way they keep station well. Turns are somewhat of a challenge, but for the most part they do ok. Sometimes, ships will loose their place, but I don't see it as a major problem, and, in any case, it happens either way.

In an attack, a high level of disruption is likely, with or without a physics mod. I can't say if it takes longer for them to recover with ISP or not. On the basis of these few tests, it seems like it's matter of chance. In no case did a convoy break up, but if one is attacked, it seems likely they will continue with a somewhat altered organization.

I don't see any reason for SH4 players to forgo a good physics mod, think that ISP or any other mod is going to harm convoys. Convoys will react to threats and become disrupted either way.

I made a bunch of screen shots, but frankly, they don't really tell any more than what I can say here. Maybe I'll post a few later. Possibly, a denser convoy would have some real trouble (collisions and such), but I think that is something to be fixed on that end.

Easily accomplished!

Just disable ISP, open it up, and take out the scene.dat file. All weather/wave changes are in that.

I hope people are using the ISP 2.x patch. If you install it and follow the instructions, you should have more bearable weather. Or, you can follow the above procedure, and have normal/vanilla weather.

Thank-you.

Typical convoys may be crammed into a smaller space than the one I crafted. This could make for messier attacks, but I'll leave that to others to test or discover.

I was going to do a naval TF, but I figure if a merchant convoy can hold together, a TF should do at least as well.


Btw, the spacing I used was diagramed in Roscoe's U.S. Destroyer Operations of WWII. I consider it to have worked well.





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I did notice what seemed odd about the convoy turning style/method, that is worth mentioning. It could be useful to anyone who is changing or developing a SH campaign. This occurred with or without ISP.

We might assume the convoys ships in a column would turn simultaneously, but they didn't do that.

We might think the lead ship in a column would turn, and the following ships would simply turn the same way, as they reached that point in space, where the first turned. They didn't do that either.

What happens is that the first in column will turn, and the following ships will turn to different angles, in such a way that the 'tail' of the convoy will swing out. This makes for a jumbled appearance, if one views it while it is in process. Below is my drawing of what it looks like:

Looking at the left column (the inside column), one can see the leading ship at the new course, the 2nd at a lesser angle, the 3rd and 4th actually turning in the opposite direction! It looks messy, yet seems to get the job done. I think the inside column tends to be jumbled more than the others. (If the ships are jammed very tight into the convoy, it could lead to difficulties.)

If anybody knows about convoy procedures, and can shed some light on this, don't hesitate to help us out.

Yeah, makes sense.

Ah, that's an interesting comparison.