Unlike structures on land where a floor refers to something horizontal that you can stand on, floors on ships are the transverse stiffeners mounted vertically on the ship’s bottom. Floor structure is continuous from the center to the side plating and supports the inner shell (tank top). They may either be solid plates (no cut holes except small half round drain holes at the bottom part) or plates with cut lightening holes .
Solid Floors
It is the easiest to comprehend, and consists of a solid plate, with no lightening holes cut into it (they lessen the weight of the plate and allow for the free flow of any liquids stored in the space). Normally it form a tank, below watertight bulkheads these floors are using
Plate Floor
Plate Floor is the one if the stiffener / floor plate is made of a solid plate with openings. This is done to optimize weight and also to allow free flow of fluids based on the purpose of the floor plate / part of the ship ( Like a tank)
Bracket Floor
Bracket floor is the one if the stiffener / floor plate is made of a built up section with a large opening. This is also done to optimize the weight, provided where much strength / structural integrity is not required and also on the purpose of the area of the ship
