Even well-made splices in wiring can wick up moisture, especially if they are in a boat’s bilge. Wicking, of course, can cause corrosion, prematurely ruin a splice, and cause electrical issues. To prevent this sort of thing, I suggest adding a drop or two of oil to a splice before you crimp, heat-shrink, or otherwise seal it. The oil will block salt moisture from entering and will keep the splice like new.
This article originally appeared in the September 2011 issue of Power & Motoryacht magazine.