How to Weatherproof new shoreline power cord connectors

Whatever solution is used, be wary that trapping water inside the connections is far worse than having it get wet and then dry out.

For example, I have a relation that connected two extensions and then wrapped the connection with a plastic bag and then electrical tape to "water proof" it. That didn't last long... rain got in there, corroded things and I had to put on two new ends.

The water gets in there and can't evaporate quickly, so it corrodes and then electrolysis eats away the connectors.