🚰 18. The Truth About Thru-Hulls and Dezincification
🗣️ The Myth: "The thru-hulls and valves look thick and solid. A little green patina is perfectly normal."
⚙️ The Technical Reality:
Brass is an alloy of copper and zinc. If the manufacturer used standard commercial brass (instead of Dezincification-Resistant DZR or true marine bronze), the zinc reacts with the saltwater in a destructive galvanic process.
⚠️ The Hidden Risks:
The zinc leaches entirely out of the alloy, leaving behind a porous, pinkish copper shell. The thru-hull may look solid, but the metal has become as brittle as a cracker. The moment you push hard to close a stiff valve, the entire fitting snaps off in your hand, allowing thousands of liters of water to flood the vessel in minutes.
🔬 The Evidence Method (NDT & Analys):
Mechanical resonance testing, core-scratch indicators (identifying the pinkish hue of leached copper), and advanced galvanic potential analysis of the hull.
⚖️ The Chairman's Verdict:
Below-waterline fittings are the vessel's most critical vulnerability. We do not accept visual assumptions; we physically verify the metallurgical integrity.
➡️ Secure your vessel against flooding: