Mooring: An arrangement for securing a boat.
At sea, these are large chains holding the ship in place.
At dock, it is restrained using mooring ropes that tie the ship to the dock.
Fluid Dynamics: The science of fluids (liquids and gases) - how they move, what forces act upon them, etc. Essentially, fluid dynamics investigates the properties of moving fluids.
Fenders: A device that acts to reduce the shock from impact. For ships, these are placed between the ship and the dock.
