Apparently it is. OED makes no connection either.
small boat, etc
[Ir. curach boat, little ship; also corrach boat, coracle; cf. Welsh corwg, also corwgl, cwrwgl CORACLE; these point to an OCelt. *kuruk-os, *kurok-os boat. (The spelling carrogh in Camden and his citers is prob. only a misprint.)]
marshy waste ground
[Ir. corrach marsh, Manx curragh moor, bog, fen.]