gets by the sealant
it can damage the chainplates and the area where the chainplates go through the hull, especially if it's a foam laminate deck. It is probably safest to take out the chainplate if it has been happening for a while, inspect it, swap it out if need be. Dig out any sealant
and any soft foam / glass around it, fill it in and replace the sealant. 5200 would be fine and fairly permanent. If the water is running down the same space as the chainplates you may be very glad you pulled them out to check them. It probably isn't an easy job but if it is an old boat then you may save yourself a lot of problems down the road. I get two years usually out of 5200. It sucks to get it back out... but I only do it once every two years.