user: Question: what is the total tonnage grt of the cargo ship(s) sunk or captured on 4 feb 16?
Columns: ['Date', 'Ship', 'Type', 'Nationality', 'Tonnage GRT']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['11 Jan 16', 'Corbridge', 'Cargo ship', 'United Kingdom', 3687.0]
SQL:

assistant: SELECT SUM("Tonnage GRT") FROM "Table" WHERE "Type" = 'cargo ship' AND "Date" = '4 feb 16';