Table: chiwawa_oiler
Columns: name
original_name
commissioned
final_decommission
fate

Question: When was the ship that had a fate of 'converted to laker, 1961; still in service' commissioned?
SQL: SELECT "commissioned" FROM chiwawa_oiler WHERE "fate" = 'converted to laker, 1961; still in service'

Question: When was the ship originally named sachem finally decommissioned?
SQL: SELECT "final_decommission" FROM chiwawa_oiler WHERE "original_name" = 'sachem'