Laden meaning loaded aboard vessel and Displacement the weight of water displaced by the immersed volume of a ship's hull, exactly equivalent to the weight of the whole ship.
The displacement is usually measured in Ibs or Kg: 1Kg = 2.2 Ibs.
The Laden Displacement is the weight of the vessel including all the added accessories on the boat including sails, stores and crew.
Basically calculating how far the water goes up the wall. For example; taking a bath is you displacing water in a tub.
So if you go over la maximum laden displacement of a vessel, this is what happens...