Threadfin
03-11-06, 01:58 PM
I know plenty of guys around here already have their own methods for doing manual targeting, but I wrote little piece a few days ago and thought I'd post it in case it might help someone, or give you something new to think about.
----------------------------------------------------
The term manual TDC implies that the player is manipulating the dials of the TDC, which is certainly possible in SH3, and sometimes necessary, and always fun to do. However, this post will be about manual targeting. This means the player is determining four important pieces of the targeting solution -- target ID, range, angle-on-bow and speed. On a U-boat, the Captain (or sometimes the exec) would be responsible for making periscope observations of the target. From these, the target's position, course and speed were determined, and the Torpedo Data Computer, or TDC, would calculate the proper gyro angle to ensure the torpedos ran on target. Therefore, the accuracy of the torpedos is a direct reflection of the acuracy of the observations made by the skipper. The method described here is essentially SH3's modelling of the true role of the Captain in a submerged torpedo attack. As mentioned, the player can 'twist the dials' if he pleases, but for this piece we will leave that to the weapons officer so to speak, and enter our observations via the datapad.
Difficulty settings are 88%, with only Map Contact Update enabled. In my opinion, having MCU enabled is in essence modelling the information that would be available to the skipper via voice communications with his officers and sensor station men. The navigator would be plotting the boat and the target, the soundman would be tracking the targets and reporting on speed and bearing, etc. This info is displyed to the player via the map if MCU is enabled, though with unfailing accuracy.
Interception:
Some targets will be aquired visually, some by sound and some by radio position report, or the contacts that appear out of nowhere on your map. It's up to the skipper to make the most of each contact. In all cases except against fast moving warships, the player holds tactical initiative. Do not give it away by forcing the shot. Always, always, always conn your boat to an advantageous position. Positioning is the absolute key to successful attacks. We want short shots from abeam. Any other position diminishes the likelihood of success. Learn to rely on end arounds. Rarely are merchant ships making more than 10 knots in this sim, so you always have the speed to end around.
A proper endaround is done at a range where you can see the target, but the target cannot see you. Depending on visibility, light, seastate and weather, a type VII is generally safe outside of 4000 meters. Medium or heavy fog will prevent you from making a visual endaround, but in any other weather it should be possible to conduct without being sighted and with keeping the enemy in sight. Using your speed move to a position well up-course of your target, then submerge on a beam approach and let him come to you. This allows you to pick your range and angle and dictate the shot. Resist the temptation to fire at the first opportunity unless your positioning is advantageous. A 2500 meter shot from a 130 AoB is not retaining tactical control. Get your boat in postion for a 1000 meter or shorter shot from an AoB of around 80 degrees. The earlier this position can be reached, the more time is available for observations needed for an accurate warshot. Position, position, position, always think position. Your accuracy will reflect the effort you put into obtaining a proper firing position.
In visual or sound contacts the skipper will have to decide on the spot the best course of action, but what about those radio reports? Easy. Let's run an interception and attack on a contact whose position is revealed through one of our regular radio position reports. U-123, type IXB, on patrol in the North Atlantic, January 1941 recieves one of these reports.
http://home.comcast.net/~dbond41/mt1.jpg
First thing to do is click on the target to see it's 'speed'. This will be shown as one of 5 -- stationary, slow, medium, fast, or very fast. Stationary, consider yourself lucky. Slow is all speeds from 1 to 7 knots. Medium is all speeds from 8 to 13 knots. Fast is all from 14 to 25? And Very fast is over 25. I am certain of slow, but I do not know if 13 knots falls under medium or fast. And I do not know the exact cutoff for fast to very fast. Regardless, in terms of merchant shipping, we only need to be concerned with speeds up to medium, except in the case of tankers or liners. Tankers can indeed be, and often are, making fast speeds of about 14 knots. Liners sailing alone are almost always making 21 knots.
Knowing the generic speed range gives us the necessary info for interception, and a framework for the speed settings we will enter into the TDC here shortly. If, for example, I click the icon and it shows medium, I'll know that if I generate a speed of 4 knots, or 14 knots, it's in error. Only a speed of 8-13 knots in this case is possibly accurate, providing the target does not change speed, which is rare unless the player's presence is revealed through sighting or attack.
In the case shown here the generic speed is revealed as medium. Therefore I plot a course to intersect the target's course. By making each leg here roughly equal (15km) I can ensure U-123 arrives first by using speed. Use the target's 'tail wake' to set the second leg. Here we ring up ahead standard for 15 knots, likely 6-7 knots faster than our medium speed target, and unless the target changes course, it guarantees we arrive at the intersection first. (More margin is generally preferable, it's better to arrive too early than too late. But here the short distance means a guaranteed intercept. The medium speed target could be making up to 13 knots, but my experience in SH3 told me it would be making 8 or 9 knots) This type of plotting takes exactly 5 seconds once you get the idea. There are lots of fancy, intricate methods for plotting an interception floating around out there, but why make it difficult? Just plot two even legs, or a little more for the target's leg, ensure your boat is faster, and if you arrive early just trace the reciprocal of the target's course. Simple. And besides, if you arrive a little behind where you want, the last thousand yards is always run by your torpedos.
http://home.comcast.net/~dbond41/mt2.jpg
In a few minutes the sighting is made. A couple of quick measurements show U-123 about 2,200 meters from the intersection, and the target about 4,200 meters. So we are ahead, just as we want to be.
http://home.comcast.net/~dbond41/mt3.jpg
Identification
We want to attempt to to identify the target as early as possible. The ID is important, because the ship the player enters is used as the basis for the mast heights, which are then used to determine range with the stadimeter. A mistaken identification will almost certainly result in inaccurate range readings, and this error will domino down through subsequent calculations. A look through the UZO shows our target to be a C3 cargo. I can see the lifeboats stacked astern, a dead giveaway, and also the very large diameter stack. To ID the ship, open the recog book to the right page, and enter a checkmark in the box at the lower right, like this
http://home.comcast.net/~dbond41/mt4.jpg
From this point on, the player needs only to click the word ship on the datapad to return to the proper page of the recog book.
When the target is about 5000 meters U-123 submerges to avoid detection and continues on at ahead full. We want to reach a position about 1000 meters off the target's track, come to a full stop, and take speed readings for the TDC.
Attack
Range
Once we reach a position that will leave us with the desired shot, 1000 meters in this case, we come to a full stop by running some backscrew to slow quickly. Be sure to put rudder amidship. As we are coming to a stop we can make range and AoB observations. To set the range, lock the target with L key, then click on the word range on the datapad, then the crosshair icon that appears. This activates the stadimeter. This introduces a new horizontal line on your periscope (or UZO if surfaced). To get an accurate range you must put the lower line on the target's waterline, and the upper line on the top of the target's tallest mast. Using the mouse you can adjust the separation, and when satisfied, click. This will set a range into the datapad. This can be challenging in rough seas, and you can use the contol key in conjunction with the arrow keys to try and center the scope for a good reading. Don't get too caught up in being absolutely precise and steady. After a while you can set the separation and judge as it swings up and down over the target, then click when satisfied. Take as many readings as you want, then click the check mark on the datapad to enter the range into the TDC.
http://home.comcast.net/~dbond41/tm6.jpg
Angle-on-bow (AoB)
Next we need to estimate the Angle-on-bow. This may be the most difficult part of the process, but an accurate speed and resulting solution are very dependant on an accurate AoB. AoB is the angle formed by the target's longitudinal axis and the line of sight from the target to the player's boat. It might help to think of standing on the target's bridge and looking at the U-boat. The angle from the bow to the sub is the AoB. When the player is directly ahead it is an AoB of 0. Directly behind is 180. Either beam is 90, and is differentiated by adding starboard or port to the AoB. This is always off the target. So if your are on the target's starboard beam, the AoB is 90 stb.
This takes practice and some experience doing it. I might recommend practicing with weapon officer assistance. Make your call, then click on the WO to see how close you were. Of course the protractor can be used for this, though I do it visually, as was done in reality. But whatever works for you to obtain an accurate AoB.
To set the AoB, click on AoB on the datapad. An icon of a ship will appear, and you can drag the AoB indicator around to set it. When satisfied, click the checkmark to enter the AoB into the TDC.
http://home.comcast.net/~dbond41/mt7.jpg
Speed
Now that we have the ID, range and AoB, we need to determine speed. The TDC computes the speed by measuring the angular change of the optic based on the range and AoB readings we have entered. I think it's extremely important to be stopped when taking a speed reading, as any movement by your boat affects the amount of angular change used to calculate the speed. To get the speed, lock the target with L. Click the word speed on the datapad and a small stopwatch icon will appear. Click this to begin the speed reading then click again after the desired interval and a speed will be shown on the datapad. A minimum of about 6 seconds is required, though longer should result in more accurate readings. The sharper the angle, the less the rate of angular change, and the more difficult it is to obtain accurate speed readings. The sharper the angle, the longer your speed timings should be. In most cases I use readings of 10-20 seconds. I will take several, sometimes many, depending on how sure I am of a correct speed. It can be a good idea to get range and AoB, take a few speed readings, re-do the range and AoB, take more speeds, and so on until you are reasonably certain you have an accurate reading. Again, remember the generic speed from clicking the icon on the map, and ensure your speed reading here falls within the range. In the case of convoys, you may get a report giving exact speed, and it's then easy to get it right (and this can be entered by true manual TDC, that is, twisting the dials on F6 screen).
Here, my first reading of 20 seconds nets 6 knots, which I suspect is slow for a 'medium speed' target.
http://home.comcast.net/~dbond41/mt8.jpg
I believe this is due to an overestimation of the AoB, which I had at 30, but was probably closer to 20. Subsequent re-readings though generate 8 knots and that is entered into the TDC by clicking the checkmark on the datapad. The AoB will of course continue to 'broaden', or increase, and the range will diminish, as the target moves across your front.
The Shot
Now I am satisfied with the speed entered, and I can now set the shot. In essence you determine the shot ahead of time. You predict where the target will be when you take the shot, since this has to be entered in the TDC some time ahead of actually taking the shot. It's up to you how soon before firing you wish to update, but against a non-maneuvering target making a steady speed this point is easy to predict in advance. Here, we double check the range to the firing point, 1000 meters. By 'fudging' the stadimeter, meaning taking an intentionally wrong oversize reading I can set the range at 1000 meters, even thoughthe target is still 1500 meters away. I can also predict the target's AoB at firing, and choose 80 starboard in this case. Ensure all info is entered in the TDC by clicking the checkmark on the datapad. Many a fine shot has been foiled by forgetting this last click of the checkmark. At this point I always give a look at the gyro angle as a failsafe. Seeing a gyro angle you wouldn't expect can reveal a reversed AoB or a stern tube selected.
http://home.comcast.net/~dbond41/mt9.jpg
----------------------------------------------------
The term manual TDC implies that the player is manipulating the dials of the TDC, which is certainly possible in SH3, and sometimes necessary, and always fun to do. However, this post will be about manual targeting. This means the player is determining four important pieces of the targeting solution -- target ID, range, angle-on-bow and speed. On a U-boat, the Captain (or sometimes the exec) would be responsible for making periscope observations of the target. From these, the target's position, course and speed were determined, and the Torpedo Data Computer, or TDC, would calculate the proper gyro angle to ensure the torpedos ran on target. Therefore, the accuracy of the torpedos is a direct reflection of the acuracy of the observations made by the skipper. The method described here is essentially SH3's modelling of the true role of the Captain in a submerged torpedo attack. As mentioned, the player can 'twist the dials' if he pleases, but for this piece we will leave that to the weapons officer so to speak, and enter our observations via the datapad.
Difficulty settings are 88%, with only Map Contact Update enabled. In my opinion, having MCU enabled is in essence modelling the information that would be available to the skipper via voice communications with his officers and sensor station men. The navigator would be plotting the boat and the target, the soundman would be tracking the targets and reporting on speed and bearing, etc. This info is displyed to the player via the map if MCU is enabled, though with unfailing accuracy.
Interception:
Some targets will be aquired visually, some by sound and some by radio position report, or the contacts that appear out of nowhere on your map. It's up to the skipper to make the most of each contact. In all cases except against fast moving warships, the player holds tactical initiative. Do not give it away by forcing the shot. Always, always, always conn your boat to an advantageous position. Positioning is the absolute key to successful attacks. We want short shots from abeam. Any other position diminishes the likelihood of success. Learn to rely on end arounds. Rarely are merchant ships making more than 10 knots in this sim, so you always have the speed to end around.
A proper endaround is done at a range where you can see the target, but the target cannot see you. Depending on visibility, light, seastate and weather, a type VII is generally safe outside of 4000 meters. Medium or heavy fog will prevent you from making a visual endaround, but in any other weather it should be possible to conduct without being sighted and with keeping the enemy in sight. Using your speed move to a position well up-course of your target, then submerge on a beam approach and let him come to you. This allows you to pick your range and angle and dictate the shot. Resist the temptation to fire at the first opportunity unless your positioning is advantageous. A 2500 meter shot from a 130 AoB is not retaining tactical control. Get your boat in postion for a 1000 meter or shorter shot from an AoB of around 80 degrees. The earlier this position can be reached, the more time is available for observations needed for an accurate warshot. Position, position, position, always think position. Your accuracy will reflect the effort you put into obtaining a proper firing position.
In visual or sound contacts the skipper will have to decide on the spot the best course of action, but what about those radio reports? Easy. Let's run an interception and attack on a contact whose position is revealed through one of our regular radio position reports. U-123, type IXB, on patrol in the North Atlantic, January 1941 recieves one of these reports.
http://home.comcast.net/~dbond41/mt1.jpg
First thing to do is click on the target to see it's 'speed'. This will be shown as one of 5 -- stationary, slow, medium, fast, or very fast. Stationary, consider yourself lucky. Slow is all speeds from 1 to 7 knots. Medium is all speeds from 8 to 13 knots. Fast is all from 14 to 25? And Very fast is over 25. I am certain of slow, but I do not know if 13 knots falls under medium or fast. And I do not know the exact cutoff for fast to very fast. Regardless, in terms of merchant shipping, we only need to be concerned with speeds up to medium, except in the case of tankers or liners. Tankers can indeed be, and often are, making fast speeds of about 14 knots. Liners sailing alone are almost always making 21 knots.
Knowing the generic speed range gives us the necessary info for interception, and a framework for the speed settings we will enter into the TDC here shortly. If, for example, I click the icon and it shows medium, I'll know that if I generate a speed of 4 knots, or 14 knots, it's in error. Only a speed of 8-13 knots in this case is possibly accurate, providing the target does not change speed, which is rare unless the player's presence is revealed through sighting or attack.
In the case shown here the generic speed is revealed as medium. Therefore I plot a course to intersect the target's course. By making each leg here roughly equal (15km) I can ensure U-123 arrives first by using speed. Use the target's 'tail wake' to set the second leg. Here we ring up ahead standard for 15 knots, likely 6-7 knots faster than our medium speed target, and unless the target changes course, it guarantees we arrive at the intersection first. (More margin is generally preferable, it's better to arrive too early than too late. But here the short distance means a guaranteed intercept. The medium speed target could be making up to 13 knots, but my experience in SH3 told me it would be making 8 or 9 knots) This type of plotting takes exactly 5 seconds once you get the idea. There are lots of fancy, intricate methods for plotting an interception floating around out there, but why make it difficult? Just plot two even legs, or a little more for the target's leg, ensure your boat is faster, and if you arrive early just trace the reciprocal of the target's course. Simple. And besides, if you arrive a little behind where you want, the last thousand yards is always run by your torpedos.
http://home.comcast.net/~dbond41/mt2.jpg
In a few minutes the sighting is made. A couple of quick measurements show U-123 about 2,200 meters from the intersection, and the target about 4,200 meters. So we are ahead, just as we want to be.
http://home.comcast.net/~dbond41/mt3.jpg
Identification
We want to attempt to to identify the target as early as possible. The ID is important, because the ship the player enters is used as the basis for the mast heights, which are then used to determine range with the stadimeter. A mistaken identification will almost certainly result in inaccurate range readings, and this error will domino down through subsequent calculations. A look through the UZO shows our target to be a C3 cargo. I can see the lifeboats stacked astern, a dead giveaway, and also the very large diameter stack. To ID the ship, open the recog book to the right page, and enter a checkmark in the box at the lower right, like this
http://home.comcast.net/~dbond41/mt4.jpg
From this point on, the player needs only to click the word ship on the datapad to return to the proper page of the recog book.
When the target is about 5000 meters U-123 submerges to avoid detection and continues on at ahead full. We want to reach a position about 1000 meters off the target's track, come to a full stop, and take speed readings for the TDC.
Attack
Range
Once we reach a position that will leave us with the desired shot, 1000 meters in this case, we come to a full stop by running some backscrew to slow quickly. Be sure to put rudder amidship. As we are coming to a stop we can make range and AoB observations. To set the range, lock the target with L key, then click on the word range on the datapad, then the crosshair icon that appears. This activates the stadimeter. This introduces a new horizontal line on your periscope (or UZO if surfaced). To get an accurate range you must put the lower line on the target's waterline, and the upper line on the top of the target's tallest mast. Using the mouse you can adjust the separation, and when satisfied, click. This will set a range into the datapad. This can be challenging in rough seas, and you can use the contol key in conjunction with the arrow keys to try and center the scope for a good reading. Don't get too caught up in being absolutely precise and steady. After a while you can set the separation and judge as it swings up and down over the target, then click when satisfied. Take as many readings as you want, then click the check mark on the datapad to enter the range into the TDC.
http://home.comcast.net/~dbond41/tm6.jpg
Angle-on-bow (AoB)
Next we need to estimate the Angle-on-bow. This may be the most difficult part of the process, but an accurate speed and resulting solution are very dependant on an accurate AoB. AoB is the angle formed by the target's longitudinal axis and the line of sight from the target to the player's boat. It might help to think of standing on the target's bridge and looking at the U-boat. The angle from the bow to the sub is the AoB. When the player is directly ahead it is an AoB of 0. Directly behind is 180. Either beam is 90, and is differentiated by adding starboard or port to the AoB. This is always off the target. So if your are on the target's starboard beam, the AoB is 90 stb.
This takes practice and some experience doing it. I might recommend practicing with weapon officer assistance. Make your call, then click on the WO to see how close you were. Of course the protractor can be used for this, though I do it visually, as was done in reality. But whatever works for you to obtain an accurate AoB.
To set the AoB, click on AoB on the datapad. An icon of a ship will appear, and you can drag the AoB indicator around to set it. When satisfied, click the checkmark to enter the AoB into the TDC.
http://home.comcast.net/~dbond41/mt7.jpg
Speed
Now that we have the ID, range and AoB, we need to determine speed. The TDC computes the speed by measuring the angular change of the optic based on the range and AoB readings we have entered. I think it's extremely important to be stopped when taking a speed reading, as any movement by your boat affects the amount of angular change used to calculate the speed. To get the speed, lock the target with L. Click the word speed on the datapad and a small stopwatch icon will appear. Click this to begin the speed reading then click again after the desired interval and a speed will be shown on the datapad. A minimum of about 6 seconds is required, though longer should result in more accurate readings. The sharper the angle, the less the rate of angular change, and the more difficult it is to obtain accurate speed readings. The sharper the angle, the longer your speed timings should be. In most cases I use readings of 10-20 seconds. I will take several, sometimes many, depending on how sure I am of a correct speed. It can be a good idea to get range and AoB, take a few speed readings, re-do the range and AoB, take more speeds, and so on until you are reasonably certain you have an accurate reading. Again, remember the generic speed from clicking the icon on the map, and ensure your speed reading here falls within the range. In the case of convoys, you may get a report giving exact speed, and it's then easy to get it right (and this can be entered by true manual TDC, that is, twisting the dials on F6 screen).
Here, my first reading of 20 seconds nets 6 knots, which I suspect is slow for a 'medium speed' target.
http://home.comcast.net/~dbond41/mt8.jpg
I believe this is due to an overestimation of the AoB, which I had at 30, but was probably closer to 20. Subsequent re-readings though generate 8 knots and that is entered into the TDC by clicking the checkmark on the datapad. The AoB will of course continue to 'broaden', or increase, and the range will diminish, as the target moves across your front.
The Shot
Now I am satisfied with the speed entered, and I can now set the shot. In essence you determine the shot ahead of time. You predict where the target will be when you take the shot, since this has to be entered in the TDC some time ahead of actually taking the shot. It's up to you how soon before firing you wish to update, but against a non-maneuvering target making a steady speed this point is easy to predict in advance. Here, we double check the range to the firing point, 1000 meters. By 'fudging' the stadimeter, meaning taking an intentionally wrong oversize reading I can set the range at 1000 meters, even thoughthe target is still 1500 meters away. I can also predict the target's AoB at firing, and choose 80 starboard in this case. Ensure all info is entered in the TDC by clicking the checkmark on the datapad. Many a fine shot has been foiled by forgetting this last click of the checkmark. At this point I always give a look at the gyro angle as a failsafe. Seeing a gyro angle you wouldn't expect can reveal a reversed AoB or a stern tube selected.
http://home.comcast.net/~dbond41/mt9.jpg