CREATE TABLE table_42580 ("Ship size" TEXT, "Cargo" TEXT, "2004" TEXT, "2005" TEXT, "2006" TEXT)

What ship size had a cargo value of $46,000 in 2006?
SELECT "Ship size" FROM table_42580 WHERE "2006" = '$46,000'
SELECT "Ship size" FROM "table_42580" WHERE "2006" = '$46,000'