Just in case I missed it in my search, please have this deleted if this has been discussed at length. From what I have read on the internet, the pagoda mast was originally used on early Japanese battleships as a method to make more use of deck space by going vertical. But were they also used for the benefit of the rangefinders? Besides the fact that you could see the ships over the horizon quicker because of their height, were there any other reasons that the IJN stopped using them in later designs? Was it because of the greater size and space that the Yamato class had and therefore they felt they were not needed? From what I understand, the Yamato and Musashi could fire their guns over the horizon, and it could use its spotter plane to help with targeting. (I know that most warships had spotter planes) But would a tall pagoda mast help that class with giving the range finders a higher platform? Or would the taller superstructure just make the class more unstable?
From what I've been able to figure out, the Pagoda style of "high" started showing up in the late twenties as a way to track the shell hits further from the ship. If I'm not mistaken they were "retro fitted" to existing Fugo, Ise, and Nagato class ships pre-radar range finding developments. Don't hold me to that, but it is something that sticks in my mind for some reason.
Most battleships could fire over the horizon. Out at sea, the horizon is 12 miles, hence the measurement for the 12-mile territorial limit. A battleships gun could usually range farther than that. The Pagoda masts were in the same philosophy as American cage or tripod masts: Spotting shell splashes. Designed before shipboard aircraft were standard, or trusted.
Distance to the horizon is a function of altitude above the surrounding area. At sea this can be very roughly calculated in nautical miles by the formula 1.17 x sqrt(feet above sea level). Thus, if one is 100 feet up in a crows' nest, presuming a nice clear day, the horizon is about 11.7 nm away; if you're floating by yourself with nothing but a life jacket, and presuming no swell, the horizon is about 2 nm away.
