CREATE TABLE table_23956 ("Position" FLOAT, "Race number" TEXT, "Sail number" TEXT, "Yacht" TEXT, "State/country" TEXT, "Yacht type" TEXT, "LOA  ( Metres ) " TEXT, "Skipper" TEXT, "Elapsed time d:hh:mm:ss" TEXT)

How many sail numbers for boat skippered by Geoff Ross?
SELECT COUNT("Sail number") FROM table_23956 WHERE "Skipper" = 'Geoff Ross'
SELECT COUNT("Sail number") FROM "table_23956" WHERE "Skipper" = 'Geoff Ross'