Tips For Long Range Tracking Of Convoys

[Bobmunky]

I'm using the Op Monsum Mod & I was wondering if any of you have any tips or tricks that you use for long range tracking of convoys.
If I get a message about a convoy heading NNE Slow between Iceland & Britain but 2 or 3 hundred K's away, in the nav I set up a line NNE & try run up ahead of them the zigzag my way back down the line, but most of the time I can't find anything.

The one time I found a convoy(It may not have been the same one I was looking for) the time compression was about x2500 & all of a sudden I was at 200ft & sinking fast when it came out of it.
Should I try to memorise the convoy routes that came with the OpMonsun Mod?
Or is there any other way of predicting there route, or finding a area of heavy traffic?

[in_vino_vomitus]

Originally Posted by Bobmunky

I'm using the Op Monsum Mod & I was wondering if any of you have any tips or tricks that you use for long range tracking of convoys.
If I get a message about a convoy heading NNE Slow between Iceland & Britain but 2 or 3 hundred K's away, in the nav I set up a line NNE & try run up ahead of them the zigzag my way back down the line, but most of the time I can't find anything.

The one time I found a convoy(It may not have been the same one I was looking for) the time compression was about x2500 & all of a sudden I was at 200ft & sinking fast when it came out of it.
Should I try to memorise the convoy routes that came with the OpMonsun Mod?
Or is there any other way of predicting there route, or finding a area of heavy traffic?

First of all I'd avoid using really high time compression if there's any chance of a contact. I can't remember who said this, but I understand that TC works [and I'm going to explain this badly] by taking a snapshot of the game situation, and then another a specified interval later, then another....etc - it doesn't pay attention to intermediate stages, so if you're moving one way and a warship is moving another, in one snapshot you could be outside detection range, and in the next, close enough to throw rocks - at which point you'll snap out of TC and die. Everyone has their own limit, but mine is 1500 if I think I'm unlikely to meet anything and 500 max if I'm in bandit country. Seems to work ok so far....

As for intercepting convoys. MoBo is a pretty useful tool for plotting intercept paths, but it's not essential if you don't want to [a] fill your HD with game stuff and [b] alt-tab out of the game to do some plotting - folks who use it, me included, think it's worth its weight in gold, possibly more given that it's software and doesn't have much mass.

When you get a notification about a convoy sighting you have to make a go/no go decision pretty much straight away. If you decide to go and you don't end up with an attack then, your decision making process was faulty. Mine frequently is, Wishful thinking, low fuel and too many torpedoes will all influence you to take long shots, but when I'm being sensible this is how I think:

How far away is it? Is it moving towards me or away? I'm not too interested in the distance to its projected track, because if the thing is a couple of hundred miles away, it may well have changed course by the time I can reach it, so if I can get to it in six hours then I'll more than likely go - eight hours would be Maybe and twelve hours, probably not - unless there was some other factor in play.

Convoys are all going somewhere. If you can identify its destination, which to be honest isn't usually possible, then you're in a better position to plan your approach. I can't say I've ever managed to do this, but it's worth keeping in mind.

You're going to hear it before you see it. An obvious point, but when you make your mind up to go - plot the route you think the convoy will be on, plot its estimated position every hour, and when you get close to where it ought to be, submerge for hourly hydrophone checks. I keep track of targets by drawing a circle equal to their speed and moving it along every hour - you just have to keep in mind that where you think they are, is highly unlikely to be where they actually are unless you're really lucky, but with any luck it will be within hydrophone range at some point.

That's about it for intercepting contacts you've been given. As far as just finding them goes - and I realise I might be trying to teach you to suck eggs here - when a convoy comes into detection range, often the game will pause. When it does, come out of TC and submerge. You'll get a sound contact often enough to make it profitable. In real life U-boat crews couldn't do this, but realistically they'd be making sound checks [I tell myself]. Anyway cheat or not it works, and it's better than sailing around aimlessly waiting to see something.

Sorry this is so wordy, but I'm a wordy sort of guy - The important bit of advice is really, just to Have A Plan. Bad plans will still often work as long as they're adhered to, and once you have a plan you can refine it. The above is more or less my plan and it works for me most of the time. Just remember that most of the time you'll be deciding against chasing a distant contact. Too much uncertainty for too much fuel......

Hope this was of some help.

Good hunting

[BigWalleye]

Originally Posted by Bobmunky

I'm using the Op Monsum Mod & I was wondering if any of you have any tips or tricks that you use for long range tracking of convoys.
If I get a message about a convoy heading NNE Slow between Iceland & Britain but 2 or 3 hundred K's away, in the nav I set up a line NNE & try run up ahead of them the zigzag my way back down the line, but most of the time I can't find anything.

The one time I found a convoy(It may not have been the same one I was looking for) the time compression was about x2500 & all of a sudden I was at 200ft & sinking fast when it came out of it.
Should I try to memorise the convoy routes that came with the OpMonsun Mod?
Or is there any other way of predicting there route, or finding a area of heavy traffic?

When you get a radio report of a convoy 200 km away heading NNE at "Slow, you must consider what you don't know. You don't know the convoy's true course. It's just NNE, which means it's between N and NE. That's a 22.5 degree spread. It will take you 13 hours at 15 kts to cover the distance to the convoy's reported track. During that time, the convoy will have moved, at an estimated 6 kts, 145 km. But the uncertainty in the convoy's heading means that its location could be anywhere within 60 km of the extended NNE course. (Simple trig.) Include a speed uncertainty of 1 kt and the uncertainty along the track is 50 km. So now you have a box to search that is 60 by 50 km. That's 3000 square kilometers, a lot of ocean. Using hydrophone search - your best sensor - you can cover maybe a 25 km circle. That's about 500 square kilometers, about 17% of the area he may be in. Then you move for an hour, to get out of that 25 km circle, and search again. Meanwhile the convoy has moved for an hour, and is now about 11 km farther along its track - which you only know to +/- 11.25 degrees. Your chances of finding him are not great, and diminish significantly with each failed hydro search. Bottom line: You're flogging it!

Now, of course, if the convoy is headed toward you, all the math changes. For one thing, if it is headed straight toward you, the best-estimate intercept point is only 50 km from where he is now. So you have to take the intercept geometry into account. But chasing contacts to an intercept point 2-3 hundred kilometers away is a low-percentage strategy. It looks great in the movies, but, if you read Werner, the real U-boats didn't have much luck chasing reports a long way away either.

Calculate an intercept point. If the convoy is going to move more than 150 km before you get to the intercept point, it's out of range. If it is going to move more than 100 km, it's iffy, and you have to trade fuel burn and time off station against the possible rewards. If the intercept point is within 100 km of the convoy's reported position, "Grossefarht voraus!"

[in_vino_vomitus]

That was far better put than I managed....

[BigWalleye]

Originally Posted by in_vino_vomitus

That was far better put than I managed....

Vielen Dank!

BTW, you mentioned using MoBo. If you have a tablet or smartphone and don't mind an outrageously anachronistic cheat, there is an app called iMoBoard that will plot intercepts and PCAs. You don't have to ALT-TAB out of the game. For justification, think of it as your AI plotting party doing the calculations for you. A snazzy bit of modern technology to augment the weak abilities of your in-game crew.

[in_vino_vomitus]

Originally Posted by BigWalleye

Vielen Dank!

BTW, you mentioned using MoBo. If you have a tablet or smartphone and don't mind an outrageously anachronistic cheat, there is an app called iMoBoard that will plot intercepts and PCAs. You don't have to ALT-TAB out of the game. For justification, think of it as your AI plotting party doing the calculations for you. A snazzy bit of modern technology to augment the weak abilities of your in-game crew.

I don't think of stuff like that a s a cheat personally, after all it's not like geometry is anything new. I have a leaky ceiling to thank for a partially knackered laptop that will run MoBo well enough for game purposes and saves me alt+tabbing, which is rather an immersion killer, but on the other hand I've also found that if I scroll across to a nearby land mass, I can draw diagrams etc on that if I fancy a bit of say, TMA if the things being uncooperative that day.

On that note, it's probably a good investment of anyone's time to check out the various threads on TMA, intercept plotting, Maneuvering boards etc, because there are a lot of useful links in them.

I've said this before, but I suspect that in some ways having an army backgoun, rather than a naval one is kind of a disadvantage, because I tend to size up a situation with a glance, when there's plenty of time for deliberation - Of course it may just be me - My preferred tactic was always
to dive in and wing it - I guess we evolve tactics that match our natural inclinations, and the great thing about this game is that aftwer those tactics have let you down badly you can ask yourself: "How did I just get myself killed?"

[Bobmunky]

Thanks fellas, after going on a patrol & not seeing anything I tend to get impatient & I'll go after nearly anything that comes reasonably close.
I think if I don't see much on patrol I'll just go sit off the top of Ireland or do a run through the channel, Cheers

[in_vino_vomitus]

You'll definitely tag something in the channel, but I wouldn't go too far in.

The thing is, those convoys have to head for ports. The mouth of the channel is a bit of a choke point as is the entrance to the Irish sea [North and south.

I don't know if you've found this out yet, but you'll find that if you save with a convoy in close proximity, the game will hang up when you try to reload it, so [a] don't save with a convoy anywhere near and [b] don't overwrite the one savegame - save frequently to a separate filename, that way if for whatever reason you can't reload your current position, you can load one not too far from it.

When you find yourself a convoy it will more than make up for the wait - they tend to be huge, slow moving, with escorts that aren't too deadly - that changes later on, but in the early days it's a turkey shoot - Not that I've ever shot a turkey.....

Best of luck anyway.

[Pisces]

To figure out where you need to steer to to meet the target there are basically 2 options. As you don't know at what speed the target moves you will have to make a (worst case) estimation an go with that. The game or manual doesn't exactly say what speed-range 'slow' is (iirc), but there is a .cfg file from which you can figure this out.

1: Iteratively calculate how long it takes you to reach the target's initial position or track (you can use the end-waypoint marker for this as it calculates distance and time-to-go), and predict where he will be then (use a digital calculator, or a onscreen nomograph from a mod). Then re-measure the distance to that, and calculate how long you will take to get to this new position. And repeat the process until the difference in time and place is zero or minimal or enough for visual detection. This usually takes a few iterations.

2: Use a bit of geometry magic to derive the course to steer to with a fixed number of steps. This can be done completely on the game navigation map. The accuracy depends on how well you handle the game drawing tools. This link describes it for SH3, but SH4 isn't different enough to be a gamebreaker. Don't bother with multiplying the speeds by 10. Just use 1nm (or 1 km) for each knot of speed. The drawing will be small, but this avoids confusion later in the end.

(the reversed compass scale on the mouse cursor he uses is very useful for plotting in general, but not necessary for this method)

http://www.subsim.com/radioroom/showthread.php?t=88961

As a convoy is usually quite large, you'll run into one of it's members sooner rather than later as predicted. It all depends on how well you predicted it's speed. If you overestimate it's speed then you have to back-track along it's course. But your radar or hydrophone has a pretty large detection range, so make sure you use it if you can't find anything on the horizon. This atleast gets you a bearing to them. The course uncertainty of the target does make it harder the further away the meeting point is from the initial position. So make sure you be there ASAP. The less large the search area will be, and the less time they have to reach their next course change waypoint. It doesn't have to be flank, but at standard speed you might give away precious ground.

[BigWalleye]

Originally Posted by Pisces

To figure out where you need to steer to to meet the target there are basically 2 options. As you don't know at what speed the target moves you will have to make a (worst case) estimation an go with that. The game or manual doesn't exactly say what speed-range 'slow' is (iirc), but there is a .cfg file from which you can figure this out.

1: Iteratively calculate how long it takes you to reach the target's initial position or track (you can use the end-waypoint marker for this as it calculates distance and time-to-go), and predict where he will be then (use a digital calculator, or a onscreen nomograph from a mod). Then re-measure the distance to that, and calculate how long you will take to get to this new position. And repeat the process until the difference in time and place is zero or minimal or enough for visual detection. This usually takes a few iterations.

2: Use a bit of geometry magic to derive the course to steer to with a fixed number of steps. This can be done completely on the game navigation map. The accuracy depends on how well you handle the game drawing tools. This link describes it for SH3, but SH4 isn't different enough to be a gamebreaker. Don't bother with multiplying the speeds by 10. Just use 1nm (or 1 km) for each knot of speed. The drawing will be small, but this avoids confusion later in the end.

(the reversed compass scale on the mouse cursor he uses is very useful for plotting in general, but not necessary for this method)

http://www.subsim.com/radioroom/showthread.php?t=88961

As a convoy is usually quite large, you'll run into one of it's members sooner rather than later as predicted. It all depends on how well you predicted it's speed. If you overestimate it's speed then you have to back-track along it's course. But your radar or hydrophone has a pretty large detection range, so make sure you use it if you can't find anything on the horizon. This atleast gets you a bearing to them. The course uncertainty of the target does make it harder the further away the meeting point is from the initial position. So make sure you be there ASAP. The less large the search area will be, and the less time they have to reach their next course change waypoint. It doesn't have to be flank, but at standard speed you might give away precious ground.

As a further refinement, after I find the intercept point, I calculate the target position 1 hour later. I mark that point on his projected track, and that is the point I steer my sub to. That way, I arrive at the intercept point an hour before the target. This gives me time to 1) do a hydrophone search and 2) adjust my position for the best possible approach. (Remember, I don't know the target's exact course or speed.) Once in position, I can lay there with engines idling (Yes, they really did this!), wait for the lookout to spot the target, then submerge to PD and begin my approach. I find the slower and more methodical I am, the better my results. YMMV.

[Pisces]

In my personal experience, assuming the worst case speed (the highest of the range it is quoted to be moving at) is sufficient to get ahead of the targets in most of the cases. You'll always be ahead. You just don't know how much. But I agree on the last line though. Rushing matters usually spawns mistakes.

[BigWalleye]

Originally Posted by Pisces

In my personal experience, assuming the worst case speed (the highest of the range it is quoted to be moving at) is sufficient to get ahead of the targets in most of the cases. You'll always be ahead. You just don't know how much. But I agree on the last line though. Rushing matters usually spawns mistakes.

With all due respect, Pisces, I find your argument unconvincing. If the target is actually traveling at the maximum speed for the range specified, then you will not “always be ahead.” You will be nearly on his beam when you reach sighting distance. That is not an ideal location to begin an approach. An ahead position is much better. You will have to do an end-around to give yourself any flexibility in approach tactics, and hope that he doesn’t zig.

Worse, since you do not know his course better than +/- 11.25 degrees, you may reach the intercept point and find that he is actually 20+ km away. That’s near the limit of hydrophone detection, depending on conditions. And a hydrophone-guided stern chase can be a long and chancy affair.

That’s why I prefer to leave myself that one-hour cushion. Being early and waiting for him to come to me allows me more tactical flexibily.

Do you hunt? Getting into position early and waiting for the deer to move to you is a favored tactic, and I can vouch for the fact that it is productive.

[merc4ulfate]

When plotting intercepts for Operation Monsun I take into consideration that there is no surface radar for a long time. I will sprint to a location and then go under and listen. I might pick them up manually before the sonar man will ever hear them. I adjust course and surface, sprint ahead and go under once more and listen manually.

I find this tactic helps me find those missing convoys much better than simply running on the surface hoping for the best.

Once I find them I wait till dark and use a surface attack hitting as many ships as I can and normally wind up in the middle of the convoy out of fish and reloading. I use the deck gun and maneuver to areas away from escorts so I can reload and use the deck gun.

Sometimes I simply move through them, move ahead of them while reloading then hit them again and again until sunrise. I have take out entire convoys this way and even got a few escorts with the deck gun using it manually instead of letting the gun crew do it. Unescorted ships are like shooting fish in a coffee cup. At least until about 1943 LOL.