Full-liner, foam-injected hulls help make small boats hard to sink. Yet they create issues when it comes to installing flush-mount gunwale rod holders. Spray and wash-water can pour into the rod tubes and accumulate inside the gunwales, soaking the foam, adding weight and promoting mold and mildew. Also, cup holders can drain into wiring, causing shorts and corrosion. The solution is to install drains, allowing any water that enters to quickly exit. Here is how we installed drains on an existing set of gunwale rod holders on a full-liner boat.