Tom Cunliffe March podcast: It’s tempting, at this time of year, to take things apart just to check they’re not about to break. But it’s a dangerous game...

“If we could persuade the current to flow, it would go on flowing. The problem was, how?”


If it ain’t broke, don’t fix it! Good advice generally, especially at this time of year, but when you’re planning a cruise far from help it’s tempting to pull things apart just to make sure they aren’t on their last legs.


Take the starter motor and alternator on the Ford 4-D in my 1911 pilot cutter. The engine was fifteen years old and had already developed one or two little individualities. You’ll be familiar with the scene. It might be a particular way you have to wiggle a switch, or maybe the engine runs for ever at 1,800rpm with plenty in reserve for short bursts, but if you dial up 2,300 for more than half an hour it overheats, despite all efforts to sort it out. You know what’s going to happen, so you live with it.


I was off to Greenland and had no means of starting the engine except a rudimentary electri- cal system, so I decided that I’d send the starter and charger back to Lucas for a check-out. Back they came in smart boxes, all painted up, com- plete with the sort of invoice that wakes you in the small hours. They functioned as well as they had been doing before their holiday and away we went, bound for points north.


We’d sailed as far as Norway when the charg- ing packed up. My crew were a competent lot and I’m not just dug up myself, so we got cracking with the multimeter. An hour later we looked at one another and declared unanimously, ‘It has to be the alternator.’ But we knew it wasn’t, and I had the invoice to prove it.
The root of the problem seemed to lie in delivering enough oomph up the field wire to excite the windings. In plain English, if we could persuade the current to flow, it would go on flowing. The problem was, how? Finally, my shipmate John came up with a working idea. He deduced that the ammeter (we still had one back in the 1980s, and very useful it was too) which was connected in series, was generating enough resistance to cause our problem. His answer was to fire up the engine, open the electrical panel, produce a length of low-resistance wire and short it across the contacts for the ammeter.


The alternator then got the message and would spring into life. Once the wire was removed, the ammeter set about its business and all was well. It wasn’t con- venient and after a while the screws for the panel began to burr. We clearly hadn’t found the root of the issue, but we did have a get-you-home lashup.


Anxious lest things deteriorate further, my first job at every stopover, before even opening a beer, was to hunt down the local electrical engineers. A handsome young Scandinavian in the Faeroes spent half an hour poking around, only to point the finger at the alternator. His taciturn, huge- handed Icelandic colleague was also adamant, but both backed off on sight of my invoice.


It was only when a pragmatic American with an enviable kit of ‘Snap on’ tools made a paral- lel declaration that I invited him to strip it and take a look. Fifteen minutes later he was in the saloon with the brute in his hands, minus case.


‘Check this thing out.’ he said, as though expecting nothing else. ‘Lucas. Prince of Darkness. The slip rings are only just making contact with the brushes. Whoever rebuilt this wants a bullet.’
He came back that afternoon with a cheap- as-chips AC Delco automotive unit. It worked faultlessly for the next ten years – as mine would no doubt have done, had I been less zealous in the first place.


Tom Cunliffe