CREATE TABLE table_59848 ("Date" TEXT, "Ship" TEXT, "Nationality" TEXT, "Tonnage" FLOAT, "Fate" TEXT)

What was the tonnage on 12 september 1942?
SELECT "Tonnage" FROM table_59848 WHERE "Date" = '12 september 1942'
SELECT "Tonnage" FROM "table_59848" WHERE "Date" = '12 september 1942'