I''m not familiar with the Newport but generally it''s a simple job(if out of the water or top of post is above water line) I''ve never done it while in the water but have heard of people raising the stern by various means. Basically you just loosen the threaded top and remove the packing rings with a packing removal tool (like a small corkscrew made of stiff wire) and install the new rings. It helps to know what size packing beforehand. Cut the new rings using the old as a guide for size and install so that none of the diagonal cuts line up with each other. Tighten and recheck after a little use.