A Creative Solution to a Broken Alternator Belt

Written by Pim Van Hemmen, crew on SV Critical Path

Five days into Critical Path’s crossing from Hampton to Antigua, while motorsailing, the engine overheated.  Upon investigation, we discovered that the pulley on the Balmar alternator had begun to wiggle, causing the drive belt to come off.  The alternator had been replaced in June of this year.  Possibly, the washer or bearing behind the pulley had failed, or was never installed.  The aluminum pulley was rubbing into the alternator’s metal housing and spewing metal shavings inside the engine compartment.  A spare alternator had been on backorder.  We didn’t have one aboard, so replacing the alternator was not an option. 

Removing the pulley from the alternator’s shaft also proved to be impossible.  A JD Weld epoxy repair on the pulley did not succeed, so we sailed without an engine for the next 5 days until someone on Facebook suggested a marlinspike repair.  One of our crew made a belt out of some spare 3/16-inch line using a daisy chain (also known as a monkey’s braid).  We then spliced the ends together to give us a shorter belt that bypassed the alternator pulley and forced it onto the two remaining pulleys on the engine’s crankshaft and coolant pump shaft.  We were skeptical that it would hold for long, so we saved the belt so we could at least motor into English Harbour.  We made two spare belts in case the first belt failed, but we never needed them.  The one belt allowed us to motor into English Harbour, pick up a mooring, and later motor from the mooring to the dock.  In retrospect, had we thought of it earlier and had more faith in our handiwork, we might have shaved a day or two off our 13-day passage by motorsailing into the wind on the improvised belts, rather than sailing north and east to get to the tradewinds and spending time in multiple doldrums and lulls.  In the end, desperation turned out to be the mother of invention. 

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