The Russian shipping register has developed a regulatory and procedural requirements for vessels, which operation involves landing on the ground, called NAABSA (Not always afloat but safely aground). With the development of some remote areas of the Far East and the Far North is required unloading goods on unequipped shore in the shallow parts of the Arctic seas. The similar operations in safe mode can make the court constructed with draining hull and landing on the ground. The regulatory and methodical shipping register requirements include recommendations for strengthening the bottom structures and protect the vessel’s hull. There are also requirements for the cargo plan, general and local strength of the hull.
During experimental use of vessels that meet these requirements in the Classification Certificate is an entry about the possibility of landing on the ground during their operation with the corresponding NAABSA category.
According to the results of an experienced application requirements NAABSA vessels to be adopted by the Russian shipping register rules and enter the following additional class character symbols:
– NAABSA1 – allowed partial or full grounding on flat homogeneous sand and gravel or sandy-muddy bottoms with no forward movement in enclosed waters with excitement;
– NAABSA2 – in addition to the conditions regulated for NAABSA1 mark allowed the presence of the translational motion of the contact and stroke the bow of the bottom ground with limited options excitement and pitching;
– NAABSA3 – in addition to the conditions regulated for NAABSA2 sign grounding allowed at a given point at a distance from the water’s edge in a moored condition in terms of pitching, accompanied by shock contacts with the ground at any point of the bottom.