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twm47099 · 05-06-12, 02:09 AM

I've been trying to learn how to use different attack methods including radar only and sonar only (active and passive and passive only).

I have a practice mission (one merchant ship, dark night) that I use. I've been pretty successful using radar only (with the OTC mod) and find that the radar range agrees closely to the chart plot ranges (with the radar and sonar only attacks, I do check once I've fired the torpedoes).

Today I tried the 4 bearing passive sonar method to get course, bearing, and target speed (3 bearings with sub stationary + one more after moving to get range.) I had the sub at 70 ft so I wouldn't get any cues besides the sonar trace which I used for the bearing measurements. I did check range with active sonar once I had a plot running, but the range was more than double the predicted (and later verified range.) So far I have not had any success with using active sonar to predict range (always over estimates.)

As the passive only attack evolved, I chickened out and decided that since the range was the most questionable thing I would use a constant bearing attack (once set up I did a second 3-bearing check on target course, but was running out of time and couldn't make the run to get a check on range)

I choose a 60 degree attack, and loaded the aim bearing, AOB, and speed into the TDC. I used the attack map which showed the sonar bearing and when the sonar trace crossed the 353 degree bearing (my aim bearing) I fired one torpedo. Once I launched I rose to P depth and raised the scope so that the ship would show up on the attack map. I had calculated the ship would be at 1600 yrds when it crossed my zero bearing, but it actually measured out to 1950 yrds. The course (and actual AOB) were accurate. The torpedo hit.

Biggest issue is that it took me a long time to collect the bearings (I used 5 minutes between bearings), and a very long time to do the graphic construction (zoom in to the chart to locate the points accurately, and zoom out to extend the lines.) Thank goodness for "pause game". I bet the WWII submariners really appreciated their pause buttons

And there was not enough time to recheck range.

I am surprised that my active sonar ranges are so far off.

Tom

05-06-12, 02:09 AM	#11
twm47099 Bosun Join Date: Apr 2012 Posts: 67 Downloads: 93 Uploads: 0	I've been trying to learn how to use different attack methods including radar only and sonar only (active and passive and passive only). I have a practice mission (one merchant ship, dark night) that I use. I've been pretty successful using radar only (with the OTC mod) and find that the radar range agrees closely to the chart plot ranges (with the radar and sonar only attacks, I do check once I've fired the torpedoes). Today I tried the 4 bearing passive sonar method to get course, bearing, and target speed (3 bearings with sub stationary + one more after moving to get range.) I had the sub at 70 ft so I wouldn't get any cues besides the sonar trace which I used for the bearing measurements. I did check range with active sonar once I had a plot running, but the range was more than double the predicted (and later verified range.) So far I have not had any success with using active sonar to predict range (always over estimates.) As the passive only attack evolved, I chickened out and decided that since the range was the most questionable thing I would use a constant bearing attack (once set up I did a second 3-bearing check on target course, but was running out of time and couldn't make the run to get a check on range) I choose a 60 degree attack, and loaded the aim bearing, AOB, and speed into the TDC. I used the attack map which showed the sonar bearing and when the sonar trace crossed the 353 degree bearing (my aim bearing) I fired one torpedo. Once I launched I rose to P depth and raised the scope so that the ship would show up on the attack map. I had calculated the ship would be at 1600 yrds when it crossed my zero bearing, but it actually measured out to 1950 yrds. The course (and actual AOB) were accurate. The torpedo hit. Biggest issue is that it took me a long time to collect the bearings (I used 5 minutes between bearings), and a very long time to do the graphic construction (zoom in to the chart to locate the points accurately, and zoom out to extend the lines.) Thank goodness for "pause game". I bet the WWII submariners really appreciated their pause buttons And there was not enough time to recheck range. I am surprised that my active sonar ranges are so far off. Tom