Table: ship_info_2
Columns: ship
built
in_service_for_nal
type
tonnage

Question: The ship MS Vistafjord has what in service for NAL?
SQL: SELECT "in_service_for_nal" FROM ship_info_2 WHERE "ship" = 'ms vistafjord'

Question: The ship SSBergensfjord built before 1973 has what tonnage?
SQL: SELECT "tonnage" FROM ship_info_2 WHERE "built" < 1973 AND "ship" = 'ssbergensfjord'