Conceivably the line could be changed with the boat in the water, but it will be much more difficult. I cannot imagine how it could be done while on a trailer unless there are no supports below the swing keel, and you dig a hole under the area where the swing keel will come down so that you can access the trailing edge of the swing keel where the lifting line is attached. My 222 lifting line was/is attached with a shackle to the trailing edge of the swing keel, but on my O’Day 19, the line goes through the trailing edge of the swing keel to a counterbored hole that comes in from the side. A knot is tied in the end of the line that then resides in the counterbored hole with the line passing up through a hole in the top of the swing keel trunk to the cockpit. The counterbored hole was then filled and faired with a caulking compound of some type. Either way, it is much easier to remove the boat from the trailer while on stands to accomplish the work. If your 222 has the shackle, it would be possible to do the work with the boat in the water. You’d have to cut the old line above the splice, attach the new line to the old one and pull the new line up over the block, through the stainless tube into the cockpit. Perhaps it would be easier to use a smaller line attached to the old line, and then attach the smaller line to the new line to pull that up through to the cockpit. The new line would have been spliced on the shackle end before it was installed. It would not be easy to remove the shackle under water and reinstall it without an air supply, unless you can hold your breath longer than I can. See photos for the shackle connection and the stand to pull the trailer out from under the boat. I built one similar to this, but I found this one on line.
