Dayshot: Admittedly it looks and moves more like a worm (it's even partly made of slime blocks), but hey, it's underwater and it keeps you dry. A bit proof of concept-y, but it's a Minecraft submarine. Designed by Minecrafter Alex_you, the sub is constructed out of slime, redstone blocks and glass, with glowstone for lighting and pistons that actually move the cabin forward. The start/stop mechanism is operated by way of flint and tinder, as the video shows:
Looks like a bumpy ride. Still, some engineering. If you wanna give it a try yourself, a download link to the map with the submarine in it can be found here, in the video description.
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