When the Alternator Fails: A Westsail 32’s Close Call and How Proper Diagnosis Saved the Passage

The autopilot warning was blunt and unnerving: “Low Battery.” We had motored two straight days from Chesapeake Bay to Cape May, N.J., and had finally killed the engine a half-hour out of the inlet as evening closed in and a steady Atlantic breeze filled the sails. The batteries should have been fully charged. How could the system be low?

I climbed into the cabin of Robin, my Westsail 32, while John Morrison took the helm. The voltmeter confirmed the autopilot’s alert: both Battery One and Battery Two sat well into the yellow “low charge” range. I started the Beta engine—installed seven years earlier—and rechecked the voltmeter. Nothing. The alternator wasn’t producing charge. Without a functioning alternator we had no reliable power for running lights, communications, radar or other essential electronics for offshore sailing. Faced with nightfall and dwindling options, we turned back toward Cape May to seek help.

The next morning we tied up at a local marina. The on-duty mechanic felt he wasn’t qualified and pointed us to a shop about 40 miles north in Pleasantville. Within the hour a young mechanic was aboard Robin and quickly made a simple diagnosis: the battery cables were secured with wing nuts. He replaced them with hex nuts, tested the running engine with a multimeter and pronounced the problem fixed. For one hour’s work, parts and travel, the bill was $462.24. Expensive, but if it meant we could safely return offshore, I was satisfied.

To our surprise, the autopilot flashed “Low Battery” again the following day as we motored roughly 50 miles off New Jersey and Long Island in light conditions. We limped on for 24 hours until we could reach Newport, R.I. There the local Beta dealer was unavailable until Monday. I called Stanley Fiegenbaum, the U.S. Beta distributor, who advised what any marine electrician will tell you: check every wire and every connection—corrosion can hide anywhere and cripple a charging system.

I’m no professional mechanic, and the idea of probing unfamiliar wiring is daunting. Still, I inspected what I could and found severe corrosion at a plastic coupling that joined a dozen thin copper leads. With a tiny fingernail file I scraped away green crust on the contacts and briefly saw the engine appear to charge the batteries—then it stopped. We now faced a shrinking window to reach Rockland, Maine, where my wife Monica planned to meet me. With a Honda 2000 EU generator lashed in the cockpit as backup, we decided to press on conservatively.

On Saturday we sailed to Chatham, Massachusetts, and passed Monomoy Point on Sunday, setting a course for Rockland a little more than a day to the northeast. At 5 a.m. on Monday, with Robin about 70 miles offshore and I sleeping in the cockpit, my crewmate John called out, “What’s that smell?” I recognized it immediately as burning electrical insulation. I grabbed the extinguisher, opened the engine compartment and saw a small blue flame on top of the alternator with smoke and sparks. I shut the engine down and the blaze snuffed out. The engine was dead. With no wind we would have been stuck, but fortunately the air filled in from the east later that morning and we were able to sail the rest of the way under the spinnaker and keep making headway toward Penobscot Bay and Rockland.

By Tuesday morning we were on a Rockland city mooring. Stanley Fiegenbaum had shipped a replacement alternator and introduced me to the local Beta dealer, Johanson Boatworks, whose mechanic David “Jonesy” Jones could look at Robin in two days. When Jonesy arrived he didn’t rush aboard. He stayed in his launch, clipboard in hand, and interviewed me for 15 minutes. “I have a pattern of how I do things,” he told me. “Take in all the information first. Listen to the owner. They can tell you, ‘It used to do this; now it doesn’t do this.’ You’re gathering facts so you know what you’re dealing with before you step onto the project.”

Jonesy’s instincts took him straight to the plastic coupling I had tried to clean. He suspected intermittent or reversed current flow from a bad connection could confuse the alternator and overload the system. One by one he cut the dozen thin wires out of the coupling, hard-wired each conductor to its counterpart, and sealed every joint with heat shrink to keep moisture out. With the coupling eliminated as a failure point, he traced every remaining wire to the engine, checked the battery bank and installed the replacement alternator.

He started the engine and the voltmeter showed the batteries were charging, just as it had briefly earlier. But Jonesy didn’t stop there. He told me to run the engine for two hours, then went ashore to return later and perform a load test. The batteries passed the test confidently, and so did Jonesy. His four hours of labor came to $192—$48 per hour—and, more importantly, the repairs were done right.

With the alternator and electrical system properly diagnosed and repaired, Robin resumed cruising the New England coast. Monica joined me in Rockland and for the next two weeks we sailed without further mechanical trouble.

This article originally appeared in the March 2012 issue.