Stupid questions I should know by now

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1. What is the best nav map magnification for ploting target course & speed?
2. I am not using OLC. What is best for speed the 3.15 rule or the inbedded
speed graph on the nav map?
3. Is the protractor a good tool for getting AOB from target to U-Boat?
4. Is the ruler good for getting range from U-Boat to target?

If I enter into the TDC the speed from 2 above. The target course from several markings over a timed period + my heading (realitive target heading + my heading = true heading?). If I have the AOB from 3 above & have my target locked with TDC on automatic will I have a good shot?

I am trying to go 100% and having problems with targeting. Any help is appreciated,,,,

[A Very Super Market]

AoB and range don't really matter for TDC stuff. Bearing and speed trumps all.

All the range function affects is the stopwatch. If its set to 100m, the watch will take 30 seconds, if its 5km, it will go for 10 minutes. Range is only important if you do your planning from the periscope notepad

If you have bearing and speed, you have an idea of where your torpedo needs to go. AoB changes the path negligibly, but will change the angle of impact, but you don't need it until the very last

[Pisces]

1. What is the best nav map magnification for ploting target course & speed?
2. I am not using OLC. What is best for speed the 3.15 rule or the inbedded
speed graph on the nav map?
3. Is the protractor a good tool for getting AOB from target to U-Boat?
4. Is the ruler good for getting range from U-Boat to target?

If I enter into the TDC the speed from 2 above. The target course from several markings over a timed period + my heading (realitive target heading + my heading = true heading?). If I have the AOB from 3 above & have my target locked with TDC on automatic will I have a good shot?

I am trying to go 100% and having problems with targeting. Any help is appreciated,,,,Your understanding or use of the word "heading" might not be correct. Atleast it is a bit confusing to me what you mean.

As I like to differentiate them (and afaik mostly correct maritime terms, but I've allways been a landlubber, so may not be completely exact):
heading = direction the bow is pointing,
bearing = direction of 'looking',
relative bearing = direction you 'look' relative to your bow
true bearing = direction (of 'looking') on the map relative to north.

1. I usually have the magnification set to have the target and uboot in view on the map. So, at the most, whatevert allows max visual range (16 km) to be on the screen vertically. Further zooming out isn't neccesary. Zooming in really deep has a tendency to make my pc get laggy. That could be because I leave alot of drawing tools on the map. And zooming in much to make your drawing precise isn't practical as you need to pan the view around sometimes. Accuracy is much better gained in longer times between plots.

2. My prefference is the nomograph (distance-time-speed-thingy on the map). It's alot more flexible than just using 3m15s intervals to plot. (using the nomograph you can also calculate how far a contact progressed in X time, once you know his speed, or the time it takes to cross X distance) And imho 3m15s only get's you a rough speed indication. And only that if the target is near. Drawing a plot at max visual range the drawing/bearing report inaccuracy comes into play, 1 degree is 300m wide at 16km. If the bearing has drifted to the next degree it could mess up your speed measurement: you could get distances on the map between 400m and 1000m if the real moved distance was 700m (@ 7 kts). It's better to get more plots and average the total distance. Or just wait 15 minutes or longer and use the nomograph to calculate the average speed between 2 plots.

3. Using the protractor to measure AOB graphically you need to know first where the target is on the map, and where his course (same as heading) is pointing to. With that settled the protractor is more accurate than you can ever enter into the AOB dial of the TDC. When setting this dial, make sure the periscope is pointing to the target right after you measured on the map, BUT DON'T lock the scope on the target. If the scope moves (drifts) the set AOB is matched to the wrong bearing if you take to long to do it. If the movement or drift is slow/hardly noticeable it might not be such a big problem. But when the target is close the drift might be quick. There is no real reason to lock the target during manual targeting based on plotting. Just getting the scope line on the approximate center or consistantly the same structure will do. The notepad procedure wants you to lock the scope just as way to transmit recognition manual ID info to the stadimeter (mastheight), and to measure the bearingdrift during the speed measurement (in a rather unrealistic lazy way).

4. Same as 3. Measuring the range graphically requires a (current) position plot on the map. But that's obvious I think. The number displays rounded to every 0.1km which is just as accurate as the watchofficer does. Some people consider this roundoff a bug. I don't, the number changes perfectly centered around the exact number. i.e. exact 5km is midway between where 4.9 changes to 5.0, and where 5.0 changes to 5.1. Remember the human eye/brain can never give crisp distances like a ruler. Aside from that the 100m resolution of the watch officer is somewhat of a cheat anyway. He could never be that good and reliable in reality. Aside from that, depending on the firing situation, range is usually not a big factor in the end of the shooting proces (thinking about the 'across target track'-situation here). Obviously it is a major factor in plotting courses.

Ask away if anything is still unclear.

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http://i262.photobucket.com/albums/ii113/laufen345/ThankU1.gifPisces. Understandable.