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-   -   How to intercept? (https://www.subsim.com/radioroom/showthread.php?t=214518)

desirableroasted 07-15-14 12:26 AM

Quote:

Originally Posted by Zosimus (Post 2224844)
The only easy solution to that is to intercept the ship/convoy as quickly as possible. Full/flank speed with battery recharge off and prefer contacts that are closing.

Since nothing, other than a task force, moves at more than 9kt, racing off at flank speed is a fool's errand. Especially since "East" is vague and since (in GWX at least) ships and convoys can and do change course.

If I can reasonably reach an intercept point within 4-5 hours, without turning my mission inside out, I will. Can't hurt, right? But banging off 10-12 hours a full flank.... tried that many times. Not worth it. And, yes, I am an ace at trigonometry, but the game simulates uncertainty very well.

The point is to conserve fuel so as to have as long a patrol as possible. More time on the lake, more targets, more kills. Zipping around every time BDU burps is the fastest way home with nothing in the bag.

Pistoliero 07-15-14 01:08 AM

Quote:

Originally Posted by desirableroasted (Post 2224876)
The point is to conserve fuel so as to have as long a patrol as possible. More time on the lake, more targets, more kills. Zipping around every time BDU burps is the fastest way home with nothing in the bag.

Not sure about conserving fuel, I use flank speed for intercept and rarely reach even 75% fuel remaining by the time, when all torpedoes are spent and I have to return to base.
Sure some common sense helps (don't interecept targets which are fast and moving away, don't interecept single ships 400km away etc), but it seems like only type II boats suffer from any sort of fuel shortage.

banryu79 07-15-14 06:16 AM

Quote:

Originally Posted by Zosimus (Post 2224844)
The only easy solution to that is to intercept the ship/convoy as quickly as possible. Full/flank speed with battery recharge off and prefer contacts that are closing.

When I receive a distant radio contact from BdU I do the following, just to tackle with the issue highlithed above:
1) mark down the contact reported position.
2) with the ruler plot 3 possible course: the 'exact' one and the two '+10°/-10°' courses.
3) On each course I mark down the theoretical position of the contact for each hour passed since contact position reported hour (I choose the highest among the possible theoretical contact speeds).

Then I plot I circle of 22 Km radius (max hydroph. range) and move it as farthest along the three plotted routes as possible till it still can intercept all three course-lines.

That is the maximun "area" along contact path I want to be able to intercept in time, so given my position and the total estimated time needed for the contat to get to that "area" I plot my intercept run and I'm able to compute the minimum speed I need to run.

With that "minimum speed to intercept" on my hands I can evaluate if, where, when and at which speed to actually intercept that contact. I usually do well with this method, and I rarely need to run at "ahead full" (Type VIIB) let alone "ahead flank".
My tipical intercept run speed is in the range 9-12 knoten.

BigWalleye 07-15-14 06:26 AM

Quote:

Originally Posted by banryu79 (Post 2224903)
When I receive a distant radio contact from BdU I do the following, just to tackle with the issue highlithed above:
1) mark down the contact reported position.
2) with the ruler plot 3 possible course: the 'exact' one and the two '+10°/-10°' courses.
3) On each course I mark down the theoretical position of the contact for each hour passed since contact position reported hour.

Then I plot I circle of 22 Km radius (max hydroph. range) and move it as farthest along the three plotted routes as possible till it still can intercept all three course-lines.

That is the maximun "area" along contact path I want to be able to intercept in time, so given my position ant the total estimated time needed for the contat to get to that "area" I plot my intercept run and I'm able to compute the minimum speed I need to run.

With that "minimum speed to intercept" on my hands I can evaluate if, where, when and at which speed to actually intercept that contact. I usually do well with this method, and I rarely need to run at "ahead full" (Type VIIB) let alone "ahead flank".
My tipical intercept run speed is in the range 9-12 knoten.

Excellent planning, Herr Kaleun!

banryu79 07-15-14 07:33 AM

Quote:

Originally Posted by BigWalleye (Post 2224905)
Excellent planning, Herr Kaleun!

Thank you, sir! :salute:

P.S.: Guess-estimation & planning are the two aspects of the game I like the most!

maillemaker 07-15-14 10:04 AM

Quote:

The point is to conserve fuel so as to have as long a patrol as possible. More time on the lake, more targets, more kills. Zipping around every time BDU burps is the fastest way home with nothing in the bag.
I almost always intercept at flank speed, and almost always run out of ammo before fuel.

About the only time fuel is a consideration is when traveling to the coat of the United States.

If it wasn't for the weather prohibiting bringing in external stores I'd probably never return to port with torpedoes.

Steve

Zosimus 07-15-14 11:37 AM

Quote:

Originally Posted by desirableroasted (Post 2224876)
Since nothing, other than a task force, moves at more than 9kt, racing off at flank speed is a fool's errand. Especially since "East" is vague and since (in GWX at least) ships and convoys can and do change course.

If I can reasonably reach an intercept point within 4-5 hours, without turning my mission inside out, I will. Can't hurt, right? But banging off 10-12 hours a full flank.... tried that many times. Not worth it. And, yes, I am an ace at trigonometry, but the game simulates uncertainty very well.

The point is to conserve fuel so as to have as long a patrol as possible. More time on the lake, more targets, more kills. Zipping around every time BDU burps is the fastest way home with nothing in the bag.

First of all, I have intercepted and sunk merchants that were moving at faster than 9 knots so I'm going to call a big BS on the first claim.

Second, you're right that convoys can and do change course–all the more reason to intercept them as soon as possible. Every extra hour you take is an increased chance that they've changed course and thrown your calculations off.

Third, if you're using a scientific calculator in the game, then imo you're cheating. You should make your intercept with the same tools that real u-boat commanders had to use. Accordingly I don't see what an expert at trig has to do with it.

Fourth, assuming you find a convoy that is moving at 7 knots (not uncommon) then surely if you find yourself behind it you sail out and around it at full speed. You're not really trying to do an end around on this baby at 10 knots, are you?!

Finally, I've never had fuel as a consideration. You usually sail off, sink a bunch of ships, and sail back without using even half your fuel. As long as your normal day-to-day operations is ahead one-third, you're fine.

BigWalleye 07-15-14 04:36 PM

Quote:

Originally Posted by Zosimus (Post 2224985)
Third, if you're using a scientific calculator in the game, then imo you're cheating. You should make your intercept with the same tools that real u-boat commanders had to use. Accordingly I don't see what an expert at trig has to do with it.

Whoa! "Cheating" seems a harsh term to toss around at someone who plays the game differently than you do. "The same tools that real U-boat commanders had to use" would have to include a plotting party of officers and POs who were themselves trained to be "expert at trig." Because the U-boat commander didn't waste his time drawing lines on a chart. The navigator and the plotting party did, using the best available high-tech tools - slide rules and tables of logarithms. Whether you use an HP 11C or beads on a string, without a plotting party we cannot begin to approach the way real U-boat commanders did it

Do you use the stadimeter to measure range? Because real U-boat commanders didn't. Only Typ IIs and the oldest Typ VIIs had them. Is it cheating to let the computer measure the angles for you?

Do you use a periscope with 10x magnification? Because real U-boat commanders had to live with 6x magnification. Is it cheating to get a better view than was ever possible on a U-boat?

Do you use binoculars with a built-in gyrocompass readout? Because real U-boat commanders never had such devices. It's much farther beyond WW2 technology than a scientific calculator. Is it cheating when you use a device which is state-of-the-art a half-century later?

Do you use the mod called RND campaign layers with zigzagging units for GWX and NYGM? Real U-boat commanders had to deal with zigzagging, maneuvering convoys. Is it cheating to know that your contact will almost certainly hold its last reported course?

Do you use the Flaggen chart to tell when a nation has changed sides? Real U-boat commanders had to get that information from radio transmissions, which might be delayed or missed. Is it cheating to know the date South Africa entered the war?

Do you use h.sie's Diesel Damages Fix? Real commanders knew that they couldn't run the Diesels indefinitely at maximum RPM without risking a breakdown. Is it cheating to order "Ahead Flank" and not have to worry about an engine failure, which your crew might or might not be able to repair at sea?

Each of these cases represents a trade-off which we all have had to make, between historical accuracy, game capability, and personal enjoyment. You might feel that using a scientific calculator spoils the immersion of the game - for you. I might feel that using binoculars with a built-in compass readout is just plain wrong - for me. We all play the game to enjoy it, and the way you play it is the right way for you. But there is no wrong way. And there certainly is no cheating in a single-player game. If manual targeting is too hard, turn it off. And go have fun. Because, if you are having fun, you are playing the game just the way you should play it.

banryu79 07-15-14 06:04 PM

Quote:

Originally Posted by Zosimus (Post 2224985)
Finally, I've never had fuel as a consideration. You usually sail off, sink a bunch of ships, and sail back without using even half your fuel. As long as your normal day-to-day operations is ahead one-third, you're fine.

So, if I understood it the right way you are usual to intercept your contacts using very high speeds but for day-to-day ops on your patrol grid you move "carefully" (ahead 1/3).

Funny thing, I usually do it the other way around. As I already explained, I extensively plot my contacts routes and my intercept runs in such a way to try and minimize speed. Instead I normally run my day-to-day ops (grid patrol) ad at ahead standard (>10 knoten) when navigating above surface (my strategy is to cover my over-the-surface legs, where my detection radius is limited (visually based detection) in the fastest possible way till my next underwater stop-point, where I creep at 1 knoten silent running for about 20-30 minutes (this is my best chance at picking contacts because my acoustical detection range is far larger than the visual one).

Instead I usually run ahead 1/3 for my long range transitions (to/from home port) or for my strategical deployment at medium range (changing patrol zone).

desirableroasted 07-15-14 06:40 PM

Quote:

Originally Posted by Zosimus (Post 2224985)
Third, if you're using a scientific calculator in the game, then imo you're cheating. You should make your intercept with the same tools that real u-boat commanders had to use. Accordingly I don't see what an expert at trig has to do with it.

In the nine years I have been playing, I have used only the in-game tools provided by the developers and modders. No more, no less. And I don't find intercepts difficult.

I am sure you will pick it up if it is giving you trouble. The guide presented earlier in the thread, while a bit of a "buzz kill" if you just want to go do some arcade shooting, is invaluable.

Good hunting.

Zosimus 07-16-14 08:43 AM

Quote:

Originally Posted by BigWalleye (Post 2225086)
Whoa! "Cheating" seems a harsh term to toss around at someone who plays the game differently than you do. "The same tools that real U-boat commanders had to use" would have to include a plotting party of officers and POs who were themselves trained to be "expert at trig." Because the U-boat commander didn't waste his time drawing lines on a chart. The navigator and the plotting party did, using the best available high-tech tools - slide rules and tables of logarithms. Whether you use an HP 11C or beads on a string, without a plotting party we cannot begin to approach the way real U-boat commanders did it

Do you use the stadimeter to measure range? Because real U-boat commanders didn't. Only Typ IIs and the oldest Typ VIIs had them. Is it cheating to let the computer measure the angles for you?

Do you use a periscope with 10x magnification? Because real U-boat commanders had to live with 6x magnification. Is it cheating to get a better view than was ever possible on a U-boat?

Do you use binoculars with a built-in gyrocompass readout? Because real U-boat commanders never had such devices. It's much farther beyond WW2 technology than a scientific calculator. Is it cheating when you use a device which is state-of-the-art a half-century later?

Do you use the mod called RND campaign layers with zigzagging units for GWX and NYGM? Real U-boat commanders had to deal with zigzagging, maneuvering convoys. Is it cheating to know that your contact will almost certainly hold its last reported course?

Do you use the Flaggen chart to tell when a nation has changed sides? Real U-boat commanders had to get that information from radio transmissions, which might be delayed or missed. Is it cheating to know the date South Africa entered the war?

Do you use h.sie's Diesel Damages Fix? Real commanders knew that they couldn't run the Diesels indefinitely at maximum RPM without risking a breakdown. Is it cheating to order "Ahead Flank" and not have to worry about an engine failure, which your crew might or might not be able to repair at sea?

Each of these cases represents a trade-off which we all have had to make, between historical accuracy, game capability, and personal enjoyment. You might feel that using a scientific calculator spoils the immersion of the game - for you. I might feel that using binoculars with a built-in compass readout is just plain wrong - for me. We all play the game to enjoy it, and the way you play it is the right way for you. But there is no wrong way. And there certainly is no cheating in a single-player game. If manual targeting is too hard, turn it off. And go have fun. Because, if you are having fun, you are playing the game just the way you should play it.

First of all, I don't know what a stadimeter is. When I measure range, I do it on the map with a ruler. That means I'm guessing whether the target is at 2400 or 2500 meters. It's somewhere in there. As we've covered in other threads, the range is usually not that important. Even in extreme cases it will only make a 1º difference in the TDC. Additionally you cannot put high degrees of accuracy into the TDC.

As for magnification, I didn't even know that the scope had a magnification switch. As far as I'm aware, however, the magnification only goes to 4.5x so I don't know where the 10x figure comes from. On the Uzi maybe? For weeks I've been sinking ships with the 1.5 magnification provided by the attack periscope–sometimes at ranges of up to 4 km.

As far as I'm aware, the binoculars in GWX do not include a compass. Yes, the Uzi does but the binoculars do not.

I do not use a Flaggen chart (I don't know what it is or how to use it) but so far I've only sunk English ships and those in convoys. I prefer night attacks and if the ship is lit I do not fire on it.

I do not use H.sie's diesel engines, but I don't go flank on the surface anyway. Although I cannot measure how much fuel is used by each setting, I have noticed that flank speed offers at best 1 knot of extra speed. I usually use ahead full. My first action after switching to the IXB was to determine the speed at each setting. I have a paper here on which I have written: 6, 10, 14, and 17. These numbers represent the speed I noticed at ahead slow, one-third, standard, and full. I don't have a number for flank written down because I'm not going to need it.

In conclusion, as I said, imo (which means in my opinion) using a scientific calculator in the game is cheating. As far as I'm aware, the crew didn't even use sine look-up tables. They aren't necessary. Before I learned how to draw the triangles, I used the TDC to calculate intercept courses by doubling the target ship's known or estimated velocity and feeding the data into the TDC. That gave me the right lead angle to travel at 15 knots to overtake the ship so sometimes I had to pad it a bit by, for example, adding another knot to the ship's speed if I felt I couldn't make 15 knots.

Zosimus 07-16-14 08:45 AM

Quote:

Originally Posted by banryu79 (Post 2225104)
So, if I understood it the right way you are usual to intercept your contacts using very high speeds but for day-to-day ops on your patrol grid you move "carefully" (ahead 1/3).

Funny thing, I usually do it the other way around. As I already explained, I extensively plot my contacts routes and my intercept runs in such a way to try and minimize speed. Instead I normally run my day-to-day ops (grid patrol) ad at ahead standard (>10 knoten) when navigating above surface (my strategy is to cover my over-the-surface legs, where my detection radius is limited (visually based detection) in the fastest possible way till my next underwater stop-point, where I creep at 1 knoten silent running for about 20-30 minutes (this is my best chance at picking contacts because my acoustical detection range is far larger than the visual one).

Instead I usually run ahead 1/3 for my long range transitions (to/from home port) or for my strategical deployment at medium range (changing patrol zone).

On my first outing with my u-boat (the first one with only 5 torpedoes total) I left Wilhelmshaven at ahead full. Before I reached my patrol area I got the notice that I had used up half my fuel!! Fortunately when I completely my patrol I just quit and was instantly teleported back to base. That was before I knew about realistic settings. Since then I have always left the base at ahead one third and I'm happy with that decision.

banryu79 07-16-14 09:18 AM

Quote:

Originally Posted by Zosimus (Post 2225259)
... Before I learned how to draw the triangles, I used the TDC to calculate intercept courses by doubling the target ship's known or estimated velocity and feeding the data into the TDC. That gave me the right lead angle to travel at 15 knots to overtake the ship so sometimes I had to pad it a bit by, for example, adding another knot to the ship's speed if I felt I couldn't make 15 knots.

That is most intresting, Herr Kaleun! :hmmm:
I never thought to use the TDC in such a creative way (or read about it).
Kudos to you for this idea :up:

maillemaker 07-16-14 10:05 AM

Quote:

First of all, I don't know what a stadimeter is. When I measure range, I do it on the map with a ruler. That means I'm guessing whether the target is at 2400 or 2500 meters. It's somewhere in there. As we've covered in other threads, the range is usually not that important. Even in extreme cases it will only make a 1º difference in the TDC. Additionally you cannot put high degrees of accuracy into the TDC.
http://en.wikipedia.org/wiki/Stadimeter

There are markings inside the periscope that allow you to determine range to the target based on the apparent height of the masts of the target - if you know the height of the masts.

I've got custom optics (Hitman) so I don't even know if they work for me. Anyway there are so many ships in the recognition manual for GWX I don't bother trying to hunt them down to find their specs.

I just eyeball for range, or ask my WO if we are on the surface.

Quote:

As for magnification, I didn't even know that the scope had a magnification switch. As far as I'm aware, however, the magnification only goes to 4.5x so I don't know where the 10x figure comes from.
Both periscopes have a magnification switch. The actual zoom factor depends on what mods you have installed. I think the Hitman optics gives you a 6X zoom.

Quote:

On the Uzi maybe? For weeks I've been sinking ships with the 1.5 magnification provided by the attack periscope–sometimes at ranges of up to 4 km.
That's pretty darn good shooting. How are you measuring target speed? Do you have map contacts on?

Quote:

As far as I'm aware, the binoculars in GWX do not include a compass. Yes, the Uzi does but the binoculars do not.
This is correct, though there is a mod that gives you bearing with binoculars. I've been tempted to find and install it as if you are standing on the bridge you would have some spacial perception as to which direction you were facing, which you completely lack in the stock view of the binoculars.

Quote:

I do not use a Flaggen chart (I don't know what it is or how to use it) but so far I've only sunk English ships and those in convoys. I prefer night attacks and if the ship is lit I do not fire on it.
Depending on which mods you have, in the corner of the map screen you will see a little tab, which is the corner of some "maps".

One of them is a convoy/ship route map (the one that comes in the box with the box version of the game). Another shows friendly port mine fields and sub nets. Another shows time/knot/distance conversions. Some people have a "flags" overlay. Now that I think about it, maybe the flag overlay is only visible in the scope screens?

Quote:

In conclusion, as I said, imo (which means in my opinion) using a scientific calculator in the game is cheating. As far as I'm aware, the crew didn't even use sine look-up tables. They aren't necessary.
Since I've started using no map updates, pretty much everything I do is bye guesstimation. A calculator would be of little use to me as I don't have inputs to put into it.

My primary keyboard key on the keyboard for driving the sub is the "=" key which means "Head thataway!". I usually use a default target speed of 6 knots and fire from 500-700 meters. I have probably an 80% hit rate.

Steve

Zosimus 07-16-14 10:23 AM

Quote:

Originally Posted by maillemaker (Post 2225319)
http://en.wikipedia.org/wiki/Stadimeter

There are markings inside the periscope that allow you to determine range to the target based on the apparent height of the masts of the target - if you know the height of the masts.

I've got custom optics (Hitman) so I don't even know if they work for me. Anyway there are so many ships in the recognition manual for GWX I don't bother trying to hunt them down to find their specs.

I just eyeball for range, or ask my WO if we are on the surface.

Both periscopes have a magnification switch. The actual zoom factor depends on what mods you have installed. I think the Hitman optics gives you a 6X zoom.

That's pretty darn good shooting. How are you measuring target speed? Do you have map contacts on?

This is correct, though there is a mod that gives you bearing with binoculars. I've been tempted to find and install it as if you are standing on the bridge you would have some spacial perception as to which direction you were facing, which you completely lack in the stock view of the binoculars.

Depending on which mods you have, in the corner of the map screen you will see a little tab, which is the corner of some "maps".

One of them is a convoy/ship route map (the one that comes in the box with the box version of the game). Another shows friendly port mine fields and sub nets. Another shows time/knot/distance conversions. Some people have a "flags" overlay. Now that I think about it, maybe the flag overlay is only visible in the scope screens?



Since I've started using no map updates, pretty much everything I do is bye guesstimation. A calculator would be of little use to me as I don't have inputs to put into it.

My primary keyboard key on the keyboard for driving the sub is the "=" key which means "Head thataway!". I usually use a default target speed of 6 knots and fire from 500-700 meters. I have probably an 80% hit rate.

Steve

Yes, I use map updates. If I didn't, I'd just use the four bearings method. Speed can easily be determined by measuring how far a ship has moved in 6:29. If I cannot get a visual sighting on the ship, I'll measure it using the hydroscope for 9:43. Most of the time you kind of know the speed of the ship already. If the contact shows "slow" (either by hydrophone or on the map) then that's max 7 knots. So if you calculate an intercept at 6 knots and the ship arrives before you, then he must be going at 7 knots. If you arrive before him, he must be going 4-5. If you both arrive on time, he must be going 6.

The = key doesn't work for me, but I have the integrated orders mod that lets me click on the helmsman and order him to come to bearing.

maillemaker 07-16-14 11:04 AM

Quote:

Yes, I use map updates.
It would be interesting to see what kind of hit ranges you can pull off with no map updates. :)

Steve

desirableroasted 07-16-14 12:34 PM

Quote:

Originally Posted by Zosimus (Post 2225259)
First of all, I don't know what a stadimeter is.

Which pretty much explains a lot.

maillemaker 07-16-14 01:48 PM

Quote:

Which pretty much explains a lot.
Well, to be fair, I never use mine and I've done pretty well tonnage wise. :)

If you have map contacts on, you really don't need it.

Steve

BigWalleye 07-16-14 02:21 PM

Quote:

Originally Posted by Zosimus (Post 2225321)
Yes, I use map updates.

I agree with maillemaker. You should try playing with map updates off. It really changes the game.

Quote:

Originally Posted by Zosimus (Post 2225259)
As far as I'm aware, the crew didn't even use sine look-up tables.

They did. Surviving examples of KM-issue trig tables can be found on the web.

Quote:

They aren't necessary.
They are if you are doing Real Nav. Real U-boat commanders used celestial navigation to determine their position. They didn't have a 21st century computer to draw little circles on the map. They had a navigator guy who had to calculate the boat's position. And sometimes, they had to check it themselves.

Quote:

Before I learned how to draw the triangles, I used the TDC to calculate intercept courses by doubling the target ship's known or estimated velocity and feeding the data into the TDC. That gave me the right lead angle to travel at 15 knots to overtake the ship so sometimes I had to pad it a bit by, for example, adding another knot to the ship's speed if I felt I couldn't make 15 knots.
It's called a TVR. The TDC was an American device which was quite different in function to the TVR. And I don't know if it was possible to use an historical TVR the way you describe. If not, then you are just using your computer to do the calculations for you. That would be rather like using a scientific calculator, only easier.:)

BigWalleye 07-16-14 03:09 PM

Quote:

Originally Posted by maillemaker (Post 2225379)
Well, to be fair, I never use mine and I've done pretty well tonnage wise. :)

If you have map contacts on, you really don't need it.

Steve

maillemaker, if you are using the Hitman's Optics mod, you don't have a stadimeter. Only prewar boats had them, and Hitman removed it from his mod. When using Hitman's Optics, the graticle is a very good aid to estimating range and AoB. It's quick, it's more accurate than the rectal housing group method, and you only need a generic ID (big tanker, small cargo) to use it effectively. Check Hitman's documentation that comes with the mod. It takes an hour or so of practice to get proficient, but it's way better for AoB. (Unless, of course, you are playing with map contacts on, in which case you can just read AoB off the plot.)


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