The restricted area is characterized by a great number of factors being present at the sometime. It caused that possibility of navigational accident in these areas is more then in other ones. It means the navigation safety is lower in restricted areas. The assessing of navigation safety requires the application of proper criteria, measures and factors.
The ship during process of navigation has to implement the following safety shipping conditions:
- keeping the under keel clearance,
- keeping the proper distance to navigational obstruction,
- keeping the proper air drought,
- avoid of collision with other floating craft,
In other words we can say:
The following criterion of safety assessment will be used:
- Safety under keel clearance (SUKC)
- Safety distance to structure (SDS)
- Safety distance of approach (SDA)
- Safety air drought (SAD).