CREATE TABLE table_17028 ("Ships name" TEXT, "Date entered service" TEXT, "Date withdrawn" TEXT, "Tonnage" FLOAT, "Type of Ship" TEXT)

what are all the date withdrawn for twin screw ro-ro motorship
SELECT "Date withdrawn" FROM table_17028 WHERE "Type of Ship" = 'Twin Screw Ro-Ro Motorship'
SELECT "Date withdrawn" FROM "table_17028" WHERE "Type of Ship" = 'Twin Screw Ro-Ro Motorship'