 In general a jackass barque is a sailing ship which is half square-rigged and half fore-and-aft rigged.The name appears to be an erroneous reference to a mule, which is half horse and half donkey.A five-masted jackass barque, which has probably never been built, would be equipped with square-rigged fore and main masts, with a partially square-rigged and partially fore-and-aft rigged mizzen mast, and fore-and-aft rigged jigger and spanker masts.