These are the conditions which must be met before free board is assigned to a ship and load line certificate is issued following a load line survey. Free boards are computed assuming ship to be a completely enclosed and water tight / weather tight envelop. The convention then goes onto recognize the practical need for opening in the ship and prescribes means of protection and closure of such openings. These are called condition of assignment since the assignment of computed free board is conditional upon the prescribed means of protection and closure of openings such as hatchways, doorways, ventilation, air pipes, scuppers, etc. Following are the conditions which must be met before assigning the load line.

1. Enough structural strength should be possessed.
2. Enough reserve buoyancy should be possessed.
3. Safety and protection of crew.
4. Prevent entry of water through hull.

Ships to be surveyed annually to ensure that they fulfill the condition of assignment.

Most of the condition of assignment are concerned with the water tight integrity of the ship. Hull construction should meet the highest standard laid down by the classification society. This ensures protection against flooding of the ship. The superstructure and bulkheads must be strengthened sufficiently. Some of the condition of assignment which contribute towards water tight integrity are:

1. Hatchways
2. Machinery space openings
3. Details of opening in free board
4. Details of opening in superstructure deck
5. Ventilators
6. Cargo ports
7. Air pipes
8. Scuppers
9. Side scuttles
10. Inlet and discharges

All the above parameters ensures water tight integrity and protection against flooding of compartment. If above are not water tight then during rough weather water can enter into the areas below main deck causing to reduce the free board. So, condition of assignment very much contributes towards water integrity of the ship. Also if green sea effect is not reduced and water is being accumulated on the deck, it can cause free board to reduce and add free surface effect. In rough weather if any longitudinal or transverse girder give way it can cause structural failure and water can enter area below main deck.

Because of this coaming, height of hatchways, height of sounding pipes and vent pipes are prescribed in M.S. load line rules.