I have discussed the basic calculations behind firing "straight-running" torpedoes in other posts (here, here, and here). Youtube has a couple of interesting videos showing a basic mechanical torpedo fire control computer from World War 1. It is a nice illustration of the geometry that I discussed in my previous posts on this topic. For those folks who are interested in naval history, I do recommend the Dreadnought Project website. The dreadnought folks do amazing work.
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