Plate
It is a rectangular shape steel with a certain thickness. The most common place you can see the plate in ship construction is the main deck and side of the ship.
Bar
There is only one principle difference between steel plate and steel bar. The steel bar has less cross sectional width than the steel plate.
Beam
A beam is a structural element that increases load bearing capability and avoid bending of the structure. Beams can be categorized by many types but from the point of ship construction, we need to categorize it through cross sectional shape.
For example, there are L-Shaped beams, H- Shaped beams, C-shaped beams, I-shaped beams and so on
