I'm not sure the level of interest this will generate, but I'm bored, so to hell with it. I only have a few images, but if people are interested I'll do another more indepth one. Also, sorry for the thumbnails. I forgot to resize the images and Imageshack only does 4:3 images. So, gonna show a really simplified version of tracking and firing on a basic merchant. (Adding escort's or Military ships to the mix makes the hunt more interesting, but also takes longer, so I'll pass for a initial LP) Early war this target can be deck gunned without wasting Torpedo's but the Japanese Navy very quickly learned to arm their supply ships, so I'm not risking it. Initial Contact occurs at 0632 near the Gilbert Islands. Both my PPI and A Scope radar show contact, indicating it's a vessel rather than a plane. This is good news for me, as even at night ASW Patrols can be a nasty experience. My A scope Radar and it's ranging unit is shown. Accompanying this unit is a bearing indicator that's unfortunately mounted off screen. By placing my radar in precision mode i can make the white arrow on the scope underneath the spike, giving me Range and Bearing to the target. With this, i can begin plotting his course and intercept Fast forward past the tedious course plotting, here's a fairly developed plot. This is made by repeated range and bearing plots from the Radar. As you can see, this particular skipper is Zig Zagging. Makes my life more difficult, but not by much. Here is the lifeblood of the US Submarine service. The Torpedo Data Computer was a Mechanical analogue computer and for it's time was fairly advanced. No other country had such a good method of inputting data to the Torpedoes. It required 2 people to operate it and it's large size was a pain in the already cramped control room, but it's implementation was part of the success of the US Sub fleet. With the information gathered from the plot i know the targets course and speed, so i can begin programming it! With the target now visible, it's only a matter of time before he can see us. Submarines have a very small profile and ride low in the water, so unlike the trained military spotters, this Merchant won't have seen us yet. The men at Battlestations as we go under. They'll retreat inside once the deck becomes awash. Leveled off at Periscope depth, we're nearly in firing position. With the target now in sight, i can tweak my firing solution to ensure it's accuracy with the tools visbile. The red GSP Button is the "Position Keeper", the crucial advantage the TDC Brings. By using the data i entered into the TDC, this tool predicts the position of my target. It's only as good as the info i feed it however. Here's our TDC Again. That Solution is looking pretty good. The range match's my measurements with the Stadimeter in the Periscope and the spray off the bow is consistent with the speed. Finally, the angle of the boat roughly match's my solution's projected angle. Alright, this is it. Torpedo doors are open, tubes are flooded!