Care should be taken to inspect through-hull fittings every 6 months for signs of corrosion and damage
When dissimilar metals are unavoidable, one needs to either break the ion path (keep dissimilar metals out of the water), or break the electrical path (use a plastic or rubber insulator between the dissimilar metals to break contact).
Superyacht hulls are formed from either composite plastic, low carbon or mild steel, 5000 series aluminium or lightweight aluminium alloys. Each has unique characteristics.
Through-hull fittings serve many purposes on yachts, but probably one of the most fun applications is housing underwater lights used to illuminate the water around the boat.6, and a part of Lloyd’s Registry approval. Shipyards know that before they cut a hole below Led High Bay the waterline into an otherwise perfectly good hull, the first design problem they face is a mechanical one.
Installing underwater light through-hull fittings below the waterline, if done correctly, is a safeand secure way to extend your boating fun into the night. This is the essence of American Boat and Yacht Council (ABYC) standard H27.6. Graphite fiber reinforced composites, for example, should be treated like a metal hull as graphite holds a very noble station on the galvanic series of metals and alloys, and conducts pretty much like metal.
Light fixtures must be able to survive wave slap, impact with flotsam or pier pilings, exposure to hydrocarbon fuels or solvents, and other dangers that are part of normal yachting operations. Whatever they use to plug that hole must maintain hull integrity, performing as well as any other hull section in keeping the ocean in its rightful place.
The simple rule about minimizing corrosion of metal yacht hulls is to avoid dissimilar metals, unless you want one of them to corrode, like zinc anodes do on a steel hull. A design must also work to minimize LED High Bay Lamp effects of stray electrical currents and galvanic corrosion due to dissimilar materials.