More of this Feature • Part 1: VacuFlush, and more • Part 2: Galvanic Corrosion, and More
Related Resources • Maintenance Q&A Index

How are galvanic corrosion and electrolysis different? B.E., via e-mail
Electrolysis is the chemical breakdown--otherwise known as corrosion--of an electrolyte, a liquid that can transfer ions between metals. For example, when the seawater around your boat undergoes a chemical change, that is electrolysis. It is also what happens inside your lead-acid battery when the electrolyte--battery acid--dilutes and is therefore unable to interact with the lead plates, the chemical reaction necessary to produce electricity. (Electrolytic corrosion, also known as stray-current corrosion, is caused by an external electrical current.)

Galvanic corrosion is the decomposition of one of two metals of different electrical potential--known as voltage--when they're immersed in an electrolyte. A natural battery is formed by two metals--say, a propeller made of Nibral (an alloy of nickel, bronze, and aluminum) and a prop shaft made of stainless steel--playing the role of anode and cathode, when they are immersed in seawater, an excellent current-carrying liquid. As electrons move from anode to cathode--that is, from the metal with higher electrical potential (less noble on the galvanic scale) to the one with the lower potential (more noble on the scale)--the metal deteriorates. Placing a sacrificial anode made of a metal, such as zinc, which has a high electrical potential, between the metals in the circuit will cause the zinc to decompose first and thus save the other metals.

Need help with a maintenance problem? Write to Maintenance Q & A, Power & Motoryacht, 260 Madison Ave., 8th Fl., New York, NY 10016. Fax: (917) 256-2282. e-mail: ken_kreisler@primediamags.com. No phone calls, please.

PMY Tries... Tuf Enuf
I just tried out a new product on my boat, Tuf Enuf Natural Bilge Cleaner. Actually, it's an old product--intro'd in 1993--with a new logo. Wallace and Sons of St. Augustine, Florida, bottles and sells the milky stuff that has a citrus scent both intense and Floridian. After I poured a quart into the bilge of the Scrumpy Vixen, it promptly began smelling like a freshly peeled orange, thanks to a compound called d'limonene, which the company says is derived from crushed orange peels.

What about the product's cleaning abilities? I've never been one to keep a spotless bilge, so the Scrump's nether areas were a tad grungy. Nor have I ever been one to scrub bilges with brushes and sponges, so I added a little fresh water and let the mixture slosh around for a day or so, washing-machine-style. Tuf Enuf removed some grease and grime, but not all, thereby suggesting that a complete job might call for further applications.

Since the company says the mildness of the product makes it safe on fabrics and the environment, I also tried a little on fiberglass surfaces and vinyl upholstery inside the wheelhouse. It removed smudges, dirt, and even rust stains almost instantly. Cost: $9.95 per quart and $29.95 per gallon.—Capt. Bill Pike

Wallace & Sons Phone: (800) 223-5969. www.tufenuf.com.

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