(An example of the physics with a shader pack installed)
Important Announcement for the 1.12.2-1.0.0 Release:
It is highly recommended to install all 3 mods, otherwise you won't have the blocks and items you need to actually build ships!
Valkyrien Skies aims to be the Minecraft ships mod everybody's always wanted. That means it includes interactive blocks, custom collision for walking on ships, mod compatibility, and more.
Truthfully a lot of the problems other ship mods have claimed to be as impossible and impractical are indeed quite solvable, and Valkyrien Skies remains as proof of that. A fully integrated custom control system is in the works, but for now the mod is stable enough to be used as a physics sandbox built into Minecraft.
There's are also the following addon mods available for Valkyrien Skies:
Plasma Cannons by Ice2670: curseforge.com/minecraft/mc-mods/plasmacannon
Plasma Engines by Ice2670: curseforge.com/minecraft/mc-mods/plasmaengines
Airship Battle Example: