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Rosencrantz · 07-08-08, 03:35 PM

It's very well known fact that for a new U-boat it was compulsory to carry out 66 torpedo attacks during daylight, submerged, and another 66 torpedo attacks on the surface at night. What isn't widely known is the reason for the exact number of attacks. Why exactly 66 + 66 and not for example 60 + 60 or 70 + 70, or 50 + 50? That's what I have thinking for awhile. Why 66 attacks? I have three theories now, every single of them drawn from "far distance", as far I can see.

1. Basic idea was to practise approaches from different start points relative to target. If divide 180 degrees half circle (from dead ahead to targets stern) into six equal arcs, we can see each arc covering somewhat magic 30 degrees. Now we could think there was six different positions for a submarine to start it's approach: Sector 1, dead ahead, 000 - 030 (330-360); sector 2, abeam, 030 - 060 (300 - 330); sector 3, flank, 060 - 090 (270 - 300); sector 4, flank, 090 - 120 (240 - 270); sector 5, abaft 120 - 150 (210 - 240) and sector 6, astearn, 150 - 180 (180 - 210). Was the boat in the port or the starboard side of the target didn't matter.

Now we could assume the boat had to carry on 10 attacks from each 6 position for a practise. 6 x 10 = 60 separated attacks. In the assumed final exam (vitnessed by the inspectors) boat had to carry on one attack from each point, target vessel "choosing" the "sector" for the boat as an "surprise" when making first zig. Now we have total 66 attacks (60 + 6).

The trick for the crew of the boat would be (as always) determining the targets overall course and speed, and then move out from the optimal approach course or from the normal approach course to the shortest possible attack course as fast as they ever could. Sometwhat easy thing for the inspectors to measure, with other things affecting to the overall performance of the crew.

The problem of the theory is at least the attacks from the sector 6, astearn. If the target's speed wasn't slow, the boat was in the impossible situation if trying to catch the target. Of course that kind of situation could have been build up for a practise, to test commanders will for an approach and of course the captain of the target (who knew the boat's position in the start) could set his speed so that the boat could reach the attack position with determined actions.

Theory 2. There was six different levels for the target's overall behavior, starting from the target running on the straight course with a steady speed to the target zigging wild and unforeseeable, maybe also changing his speed. (Like a destroyer going back and forth while escorting the convoy.)
Again 10 attacks for a level + exam, 1 attack per each level.

Theory 3. Theory 1 merged with theory 2. My best quess.

Comments, ideas? I'm posting this because I haven't been able to find any official documents giving description about the details.

Greetings,
-RC-

07-08-08, 03:35 PM	#1
Rosencrantz Grey Wolf Join Date: Dec 2004 Location: Finland Posts: 758 Downloads: 78 Uploads: 0	Why 66 + 66 attacks? It's very well known fact that for a new U-boat it was compulsory to carry out 66 torpedo attacks during daylight, submerged, and another 66 torpedo attacks on the surface at night. What isn't widely known is the reason for the exact number of attacks. Why exactly 66 + 66 and not for example 60 + 60 or 70 + 70, or 50 + 50? That's what I have thinking for awhile. Why 66 attacks? I have three theories now, every single of them drawn from "far distance", as far I can see. 1. Basic idea was to practise approaches from different start points relative to target. If divide 180 degrees half circle (from dead ahead to targets stern) into six equal arcs, we can see each arc covering somewhat magic 30 degrees. Now we could think there was six different positions for a submarine to start it's approach: Sector 1, dead ahead, 000 - 030 (330-360); sector 2, abeam, 030 - 060 (300 - 330); sector 3, flank, 060 - 090 (270 - 300); sector 4, flank, 090 - 120 (240 - 270); sector 5, abaft 120 - 150 (210 - 240) and sector 6, astearn, 150 - 180 (180 - 210). Was the boat in the port or the starboard side of the target didn't matter. Now we could assume the boat had to carry on 10 attacks from each 6 position for a practise. 6 x 10 = 60 separated attacks. In the assumed final exam (vitnessed by the inspectors) boat had to carry on one attack from each point, target vessel "choosing" the "sector" for the boat as an "surprise" when making first zig. Now we have total 66 attacks (60 + 6). The trick for the crew of the boat would be (as always) determining the targets overall course and speed, and then move out from the optimal approach course or from the normal approach course to the shortest possible attack course as fast as they ever could. Sometwhat easy thing for the inspectors to measure, with other things affecting to the overall performance of the crew. The problem of the theory is at least the attacks from the sector 6, astearn. If the target's speed wasn't slow, the boat was in the impossible situation if trying to catch the target. Of course that kind of situation could have been build up for a practise, to test commanders will for an approach and of course the captain of the target (who knew the boat's position in the start) could set his speed so that the boat could reach the attack position with determined actions. Theory 2. There was six different levels for the target's overall behavior, starting from the target running on the straight course with a steady speed to the target zigging wild and unforeseeable, maybe also changing his speed. (Like a destroyer going back and forth while escorting the convoy.) Again 10 attacks for a level + exam, 1 attack per each level. Theory 3. Theory 1 merged with theory 2. My best quess. Comments, ideas? I'm posting this because I haven't been able to find any official documents giving description about the details. Greetings, -RC- Last edited by Rosencrantz; 07-08-08 at 03:49 PM.