Had a constant drip, tighten packing stopped drip, ran boat 100miles drip came back.water flow tube is not clogged. Tightened again at dock. Ran boat 10 minutes after tightening content drip came back again. Tightened at dock again drip stopped. There is at least 2.5 inches of adjustment left but I expect the result to be the same. My question is can we replace the packing or add to the packing in the water? Should we Keep tightening? Boat is a 2003 and I don’t think the packing nut has even been moved. If it can be done in the Water should a professional handle it or can we do it? Thanks in advance.