Compartmentalisation of the shore occurs where there are major obstacles or objects, especially headlands on deeply embayed coasts. The beaches that are the most enclosed are commonly known as pocket beaches. On these type of beaches the volume of sand remains constant and are closed compartments. Littoral cells can be defined as sediment within a coast that is circulated e.g. rip currents. Littoral cells usually develop on coast which are not impeded by headlands and where longshore currents are allowed to develop.