For purpose of illustration the following pics have been edited to slide the TDC and AOB indicators closer to center.

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This one I measured his course and maneuvered to be 1000 yards off the track at about 90 degrees to the track for the perfect angle shot. He's only doing 5 knots so nothing is happening too fast to keep up with. This pic is at 3000 yards range, with me 1000 yards off the track the AOB is starboard 25.

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At 2000 yards range the AOB has only changed 7 degrees, starboard 32.

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1500 yards up to 43, the AOB starts swinging faster, in 500 yards got a 11 degree change.

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AOB 50 at 1350 yards, 7 degree change in 150 yards.

For those unaware, on the left side PK the lower ship is your sub showing the compass heading, upper is the target showing his heading. The arrow in the lower one shows the gyro angle for the torpedo, which way and how much it would need to turn if you fired at this moment. Upper dial arrow shows the angle at which the torpedo will hit the target, in this case about a 45 degree angle from the bow.

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Here's the shooting setup we're looking for, close to zero gyro angle and close to a 90 degree impact angle. Note the AOB shows 80 degrees but the dial in the TDC shows the torpedo impacting at 90 degrees, the difference is how long it takes a Mark 14 at 46 knots to travel 1000 yards.

Again this is the training wheels study, note the crosshairs for a 5 knot target with a zero gyro angle 46 knot torpedo show 10 degrees off center at the moment of firing. When you move up to manual targeting and no map contact realism, if you want to use the angle off firing method set the bearing for straight ahead, speed zero AOB doesn't matter if the speed is zero, click the "send range and bearing to TDC" button so the gyro angle will be zero and the fish will go straight out of the tube. Range actually doesn't matter with the angle off method, set the crosshairs at 10 degrees right (010) for a target coming from the right, a target crossing your bows left to right set for 350. Whatever the range is when he crosses the 10 degree left (or right) crosshairs you fire, and if he doesn't turn or change speed the torpedo will hit. Get to know different convoys and merchant ships and the speed they usually cruise, that will tell you if your speed guesstimations are close. Make notes on what the angle off is for different speeds and different torpedoes, for a Mark 10 you would need to lead the target by more than 10 degrees, for a task force going 20 knots you would need a lot more lead angle.

I must respectfully disagree. There is solid evidence to indicate that historically, the Approach Officer was expected to provide an observed AoB substantially more precise than "less than 30" or "more than 30" or "about 60". First, the Submarine Torpedo Fire Control Manual, SLM-1, cited repeatedly in this thread, emphasizes the importance and use of the observed AoB. SLM-1 lays out the procedures for developing a firing solution in some detail. At no point does SLM-1 imply that AoB should be derived principally from range-and-bearing data. Second, Plate VII of SLM-1, cited above by TorpX, includes a table of Aob observations stated in 5 degree intervals. SLM-1 is a training manual. If the Navigational Plotter could not expect to receive AoB data of that precision in the field, then only a poor training manual would teach him to expect it. Third, Dick O'Kane has a long passage in his book "Wahoo" describing the training regimen he set up for himself when he learned that he, the XO, was to be Approach Officer. He and other officers set up a simulator, using a ship model and an inverted binocular. He trained on this until he was proficient at judging AoB to within 5 degrees. Pete Galantin describes doing the same thing in the Attack Simulator at New London. As I said, a lot of evidence that reasonably accurate and precise AoB observations were expected of and provided by the Approach Officer.

In the game, there are several methods which players commonly use to determine AoB with an accuracy and precision of +/- 2.5 to 5 degrees. One is the Dick O'Kane Mark 1 Human Eyeball method. The SH4 Solution Solver, by gutted (http://www.subsim.com/radioroom/down...o=file&id=1358) provides a computer version of O'Kane's AoB training tool to assist in developing the needed skill. Sublynx, in his Charts Add-on v1.4, (http://www.subsim.com/radioroom/down...o=file&id=3675) includes a very useful (KM, I believe) chart of a merchant ship photographed at 5 degree intervals. The photos are annotated to show the important features to observe in making an AoB estimate. A second method, the method apparently favored by the KM, was to use the periscope graticle and a simple circular slide rule, the RAOBF. This tool is available in many SH3 mods and in OM, but not in SH4, although it is quite easy to make a hand-held version from the images provided in the mods. (It's metric, but that's just a scale factor.) Using the periscope or TBT graticle, it is possible to quickly determine first the range of the target and then the AoB. I have used a fleet-boat style graticle very successfully for both range and AoB. And, unlike the stadimeter, it is not necessary to know the exact identity of the target first. Merchants were generally of sufficiently similar dimensions that generic numbers are adequate. Once the range to the target is known, the angular length of the ship is used to calculate the AoB. Of course, if an identification can be made, then more accurate numbers can be used for both mast height and LOA.

AoB was historically determined to significantly better than +/- 15 degrees, and the same techniques are available for use in-game. Being able to determine AoB improves your approach planning. It frees you from dependence on the "God's-eye" automatic chart updating. It makes longer range shots more productive, giving you opportunities to attack targets you might not otherwise close. It extends your approach time, making firing more methodical and less hurried. - and less error-prone. And, it allows you to conduct your attacks in a way more like what was actually done historically.

Hee-hee, it's a lot like math - some people have a talent for it and others don't. My thinking is if it's a large AOB at a long distance you need to quickly figure out the general course and get closer to the track in a hurry, if it's less than 10 degrees you're close to where you need to be so you can daydream until he gets closer. The main thing is if it's less than 10 degrees it's not going to change very much until he gets a LOT closer, then it will change very quickly. Reading SILENT RUNNING recently the author (who was the TDC officer for that sub) commented that he set the AOB to the general course and speed to calculated overall speed of advance into the TDC since the complicated zigzag plan the approaching convoy was using was just too much to handle. When the targets got close enough to get an accurate range and bearing the TDC guess was only 500 yards off the original estimate. Looking at it now page 124;

"Before long Dykers had their tops in sight through the periscope. Alec Nading and Kent Lukingbeal had worked out an overall speed of advance for the convoy based on its zig plan, and I had just set that in the TDC rather than trying to estimate the convoy's many zigs and zags."

That's the worst trouble with trying to play this game on full realism, note he mentions himself on the TDC along with two other guys on the plot. He only mentions the Captain on the periscope, but there were always two - the assistant approach officer waltzed around the back side of the periscope reading off the ranges and bearings when the Captain said "mark". All the captain (or whoever was doing the periscope work) had to do was center crosshairs, adjust stadimeter, and estimate AOB, he had a whole team to do everything else. For me trying to be Captain and the entire approach team along with the crew setting torpedo speeds and depths is just too much in too little time to screw around with unrealistic realism.

Hey, it's your game. You can play it any way you want, as long as you have fun. THAT is the most important thing.

But your choice is not the only one. And, for anyone who wants to learn how to make accurate observations, it is not impossible, it is done by many players, and there are tools to help do it.

As for realism, after a point the question is not "What is realistic?" but "What you do want to simulate?" Is it more realistic to have a God-like omniscient plotting party or to have the Approach Officer do all the plotting? The correct answer is "No." That's why I did not use the word "realism" in my post. But it is possible to play it either way, and many players enjoy each alternative.

There are posters on this site who like to play at 50% difficulty, and have a ball doing it. It would be wrong to suggest that they are not playing the game the way it is supposed to be played. But it would be equally wrong to suggest that playing a 100% difficulty is either impossibly challenging or less historically accurate than playing at 50%.

I wouldn't want a new player, who has read accounts of careful, cold-blooded stalking approaches, to become turned off because he read on SubSim that the game only allows hip-shots and that the way he wants to play is impossible.

I just have one question? How to do a good estimation of speed? Several times are just guessing and if wrong, load a pre-attacking saved game.

I have read several posts, statimeter is not always a good, exact method in rough seas......and in addition the wrong in game mast height recorded in the recognition manual.

The most logic I have read is to use periscope cross, take time in how long does the ship takes to move from bow to stern and make simple maths but the problem is that "cleverly" US navy forgot to record the ships lengths, (not cool). Plotting? Well, how are you supposed to estimate speed by plotting without updated contacts on the map?

Thanks! :salute:

Plotting is the best way. That is what RL USN skippers did.

It is not easy, or effortless, but will get the job done, if applied with skill. I think people become discouraged, because they start with the mindset that they should be able to come up with a tight firing solution, after plotting only 2 or 3 points.

There are only two differences between using map contacts and plotting yourself:

1. you must do more work; that is actually plot the points yourself.

2. you must deal with a realistic level of error (observational error).

The second point is probably the sticking point for most players. Realistic errors require that more points be plotted to sort things out
, and many dislike this. It also means that there are no 'sure things'. There is a real possibility of missing the target. Again, this is a realistic part of the game. Many attacks did fail for these and other reasons.

Once you have a good number of points plotted, it is a simple matter to calculate speed. I like to calculate speed based on a rolling average of the last 3 or 4 points. Relying on the last 2 only, introduces more error, imo. I usually don't include any from a great distance, as stadimeter errors make these dubious.

You can use the 'timing by wire' method also, but you must either steer the boat so the target is crossing your bow (or stern), or use trig to compensate for the angles. I find plotting easier, and must plot anyway, in order to develop the approach properly. Also, as you point out, you must know the target length. BTW, it wasn't the Navy that forgot to include the lengths, it was Ubisoft.

You haven't read the "High Realism Tutorial" have you. This very problem is explained in the tutorial. You'll learn to plot a targets position on the Navigation Map to gain its course heading (which comes from its Angle on Bow), and estimate its speed by marking the targets position from the observations you take. The speed is learned when you know the distance between two marked points, and the time it took the target to travel between these two points. Nothing you can't learn if you read the tutorial.