if yours just locked up is prolly not frozen yet..if you are gonna work on it immediately and have a place for it , gently see if the nut turns--if it doesnt--spray with an anticorrosive ...if that doesnt work--be careful of the shaft log--will break with pressure in excess.....the shaft log in these is a bolt in bronze tube -- is subject to electroll-y-sis, wear, pitting from salt---many things over time----is a haul-out for replacement--and costly to replace....replace able with bronze bolt in or plastic.....gooood luck......be gentle woith your old girl---gooodluck....have fun with her....