In the pantheon of sailing saints, nestled between St. L. Francis Herreshoff and Father Joshua Slocum, I propose that we canonize Rudolf Diesel as the patron saint of the windless wanderer. For it was Diesel who, in 1892, had a revolutionary idea regarding the fledgling internal combustion engine. He postulated that if the compression ratio was sufficiently high as to create intense heat and a viscous fuel was injected in a vaporized form, there would be no need to introduce a high-voltage spark to create ignition.
For many years, these large-lunged thumpers did not change significantly. Their strength was in their robust simplicity. Their fault lay in their ponderous weight and sooty emissions.
Through spurts of evolutionary design, those faults have disappeared in the modern diesel. What remains is a long list of clear advantages over gasoline engines. The weight-to-power ratio now outstrips the gasoline engine, the fuel economy is approaching twice that of petrol, the emissions are markedly more environmentally friendly and, if given clean oil, fuel and air, the reliability and longevity are legendary. In the European passenger- vehicle market, diesel engines now outnumber their gasoline cousins, and of course, diesels totally dominate freight transport on the rails, highways
For the cruising sailor, however, the most critical difference is safety. Whereas gasoline is highly vaporous and explosive, diesel emits little vapor and is almost impossible to ignite. When burned, it creates far less carbon monoxide than gasoline, an important consideration in small and relatively unventilated spaces.
But diesel oil, as it is sometimes called, is a complex fuel with a long list of properties, such as lubricity, cetane rating (equivalent to octane in gasoline) stability and cold-weather performance.