Abstract: An oil tanker ship having an oil tanker hull assembly and method of operation operable to prevent oil spillage in case of an accidental hull rupture. The oil tanker assembly includes 1) an inner main tank oil cargo assembly to receive, support, and convey a primary oil cargo; and 2) an outer hull tank oil cargo assembly adapted to receive and convey a secondary oil cargo therein and mounted about and enclosing the inner main tank oil cargo assembly. The outer hull tank oil cargo assembly is provided with a plurality of compartment bulkhead assemblies operable to divide same into a plurality of spaced adjacent compartmentalized hull tanks with each one independently operable on being ruptured to prevent oil spillage into the surrounding sea water. The compartment bulkhead assemblies are each provided with an upper top surface engineered and positioned below a sea level line when obtaining a full load of oil cargo therein.