CREATE TABLE table_48871 ("Model" TEXT, "Length Over All" TEXT, "Beam" TEXT, "Sail Area" TEXT, "Crew" TEXT, "Comments" TEXT)

Which Comments has a Length Over All of 4.5m?
SELECT "Comments" FROM table_48871 WHERE "Length Over All" = '4.5m'
SELECT "Comments" FROM "table_48871" WHERE "Length Over All" = '4.5m'