Comments by "Steve Valley" (@stevevalley7835) on "HMS Devastation - Guide 221" video.

@tjokflots before GPS, they used celestial navigation: to find latitude, use a sextant to measure the angle of elevation above the horizon of Polaris, if in the northern hemisphere, or the Southern Cross, if in the southern hemisphere. Finding longitude was a much tougher nut to crack, which brings up your other question, the revolutionary invention. To find longitude, use the sextant to find noon where you are, then compare local noon to GMT shown on a chronometer (hyper accurate clock) which shows how many hours, and degrees of planet rotation, you are away from GMT. The chronometer was the revolutionary invention. The first practical chronometer was invented by John Harrison, in England, around 1761, after several years of working the problem and several previous failed attempts.
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@CTXSLPR I read somewhere along the line that the USN switch away from hammocks in the late 30s was due to the hammocks being suspected of contributing to back problems among the crew. I can't recall what the source was for that, so can't attest to it's accuracy.
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@kemarisite iirc, the Illinois class used the modern Mk IV turret, but still used the 13"/35. The Maine class, and the Arkansas class monitors, were the first to use the 12"/40. The performance of the 12"/40 was so much better than the 13'/35, once the guns had been reinforced, that I have wondered why the Illinois class were not rearmed with them. According to my 1910 USNA gunnery text, the turntable of a big gun turret is built up from common steel plate and angle iron, so making a new turntable for the Mk IVs on the Illinois class to take the 12"/40s would not seem to have been a big problem.
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@kemarisite The Navy's choices on the Illinois class are counter-intuitive, mounting obsolete guns in a new and innovative turret. I did a pretty deep dive into the 12"/40 as part of a thought exercise several months ago, working out which ships had it, and the status of all of those ships as of the end of 1914. The objective of the exercise was to find a heavy gun the US could have declared surplus and sold to the UK as armament for their monitors, if President Wilson had been as interested in helping as FDR was a generation later.
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