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I want to know the U-boat submerged (surfaced) attack process in detail from a crew member role and process point of view. Who stood where, when were measurements taken, how often, who took them, who operated what machinery, how was target data deduced, etc.
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See if this helps. Also sent it to you by PM, in case you miss this thread :salute:
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When an uboat sighted a ship (mast tip, smoke column) the captain would be called to the bridge inmediately, while the officer in command at the deck would order the uboat to put his bow to the contact bearing. This served two purposes: A) Determine if the target is moving left or right, B) Minimize own ship silhouette. As the captain arrives to the bridge, he ascertains the contact with his 8x60 binoculars. Those are more powerful than the crew ones (7x50s), because they are conceived to see better details of something already detected, and not to scan a wider area. By then the contact will have moved either left or right, and the captain will have decided -based on the area he is patrolling, possibility or air cover, etc- his course of action. Asuming he is decided to stay surfaced, he will put the boat on full power in the direction of the contact, seeing it grow above the horizon. When mast heads are clearly visible, and before the superstructure appears, the captain will have enough data to know wether it is a merchant or warship, and a rough idea of his angle on the bow (Bsed on mast separation). The next step is to order the helmsman (On the conning tower interior) a course which he considers is paralell to the target, and the navigator (Also on the conning tower) to keep a log. The captain will then watch on regular, 5 minutes intervals, wether the ship is coming closer or dissapearing below the horizon, and as such will correct the uboat's course and speed to ensure he steers a paralell course, while overtaking the enemy. Each time an observation is done, he will shout to the navigator the result of it, bearing (Obtained from the graded scale of the UZo by the IWO and called out), rough distance and AOB. Knowing that the horizon is at a distance of 9 km from the uboat's bridge, the captain will be able to estimate roughly distance to target by making a guess about the mast heigth of the enemy ship, and calculating with a simplified formula how far behind the horizon it is. It will also allow him to note how much closer/distant the ship came each 5 minutes. Comparing how fast he overtakes the target with own ship speed, he will also be able to make an estimate of enemy ship speed (Like when you overtake another aumobile in the highway slowly, you know he is in paralell course to you, and more or less how much slower than you)
Comparing own uboat course log and the bearings to target, the navigator will determine the zig-zag pattern of the enemy ship, and its speed and base course.
Once determined, the commander will accelerate as fast as the uboat permits and gain attack position in the front quarter of the enemy. Outside 45º left or right from the bow of the enemy, the uboat has the less chances to get close enough for a torpedo attack, specially if he needs to approach submerged. Depending on the hour of the day, the captain will decide wether to make a surfaced night attack, or a submerged day attack.
SURFACED NIGHT ATTACK:
The uboat will gain position in the front quarter of the enemy, and reverse course to approach from approximately 60-45º AOB using a dog-leg curve. This means that the uboat will proceed at moderate speed (5-8 knots) to prevent a large, phosphorescent bow wake, and will be constantly making small turns to point its bow to the target, presenting the smallest silhouette. The captain will direct the attack from the bridge, while the IWO will direct the shooting from the UZO. A petty officer will man the TDC in the conning tower, and the navigator will keep a log from the attack, as well as follow the compass repeater to give the commander an idea of the uboat's position. When the uboat approaches the target, captain and IWO will discuss its details and determine wether friend or foe, as well as its dimensions (Using naval construction porportions for ships, counting number of cargo bays and multiplying with average tonnage, etc.). Up from then, and if the attack is continued, the IWo will be constantly calling the estimated AOB, range and speed to the petty officer, who will be making inputs in the TDC so as to have a ready solution in all moments. He will make his estimates of range based on the amout of lense covered by the target (A 125 metres target wll cover the full optics at 1000 metres, half the lense at 2000 and so on), AOB based on naked eye, and speed also on naked eye, and guided by the bow and stern wake, and the general speed of movement of the enemy. He might double check his speed estimates using a chronometer and the fixed vertical line in the UZO. If the night is too dark or data are deemed not reliable, he will resort to the ones gathered during the day time end-around. The commander will be looking constantly in all directions, keeping the best situational awareness possible, specially of any possible threats, and will plan the route of escape after the shooting, while the IWo will concentrate in the firing solution.
When the IWO is ready to shoot, he will ask the commander for a constant course, a constant turn for a fan shot, or an abort of the attack, and the commander will decide the most apropiate course of action. The IWO will also instruct the petty officer the type of shooting he will do, and the fan spread if applyable. If the commander presses the attack on, he will give the IWO authorization to commence shooting, and the IWO will then shout at the TDC petty officer his last instructions and train the UZO some metres before the target. This will alow the TDC's analogic mechanism to turn all dials and compute the solution (Our modern computers do it instantly, but WW2 analog technic required some seconds before teh cascade of dials moved) The operator will shout "ready", and the IWO will wait till the target's juicy parts cross the wire for shooting. He will press the handle in the UZO column each time a torpedo has to be released. When all torpedoes have been discharged, the commander will conn the uboat out of the zone through the best route, and at maximum speed. The TDC operator will keep a log of the time to impact because the TDC shows in a partition the estimated torpedo run (And knowing the torpedo speed, he will use the chronometer to estimate the moment of impact)
SUBMERGED DAY ATTACK:
The procedure is very much the same until the moment the uboat has gained attack position, but this time it will submerge and have the captain conn and direct the attack from the periscope. He will do it from the attack one in bright light conditions, and from the observation one in low light/twilight ones. Estimates of distance, AOB, speed can no longer be done by naked eye easily, because the monocular periscope causes to lose a lot of depth perception, and therefore the captain has auxiliary tools like stadimeter or graded reticle for distance, and fixed line for speed.
VARIATIONS:
In the surfaced night attack, if the uboat found the target at night and was not able to follow it for a while in daytime, the commander will conn the uboat on paralell surfaced course and speed, at night visibility limit for the enemy, to ascertain enemy speed and course. Then he will accelerate and turn to the target to proceed as described.
In the daylight submerged attack, if the uboat had to submerge before ascertaning the target data, the commander will conn the uboat at right angles to the enemy, progressively turning to it if the bearing moves backwards, until a constant one is achieved (collision course), and will have the navigator plot the enemy course by giving him regular estimates of distance and bearing. He might however also decide to base the firing solution purely in naked eye estimates, if the situation does not allow enough plot to be done.
EDITED to correct some typos and some info.
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