4,295 supertankers ferry oil from producers to consumers on the Earth’s oceans.  If the average deck size is 3.5 acres, the oil supertanker fleet has created 15,032 acres of dry surface area (or 23 square miles, the size of Manhattan).  What if this deck surface was irrigated farmland?  An estimated 543 million acres are currently irrigated for farming in the world, feeding some 7 billion people.  The 15,032 acres of supertanker deck is .003% of this area, and could feed 63,000 people.  That’s a city the size of Waltham, MA!

The supertanker has one advantage over a traditional farm: mobility!  The course and speed of the Farmtanker (as these converted tankers are now called) can simulate the growing season for any crop growing on its deck.   As the Farmtanker descends in latitude, the length of day either increase or decreases, depending on the season.  For example, a Farmtanker is cultivating a crop of corn during the northern-hemisphere’s winter would travel deliberately into the higher latitudes as it crosses the Atlantic Ocean, increasing temperature and length of day, tricking the corn unaccustomed to growing on the move.  Indeed the timing of the beginning and end of the growing cycle of any given crop would become irrelevant: with the ship’s position setting the season, crops could be harvested and planted back-to-back.  Of course, the tankers are pulled along by a computerized kite/sail, convenient for the slow transit times necessary to simulate a suitably long growing season for on-board crops.

Perhaps as these behemoths become obsolete with the onset of peak oil (or not, as an op-ed in the NYT recently reported), this repurposing will delay their decommissioning in Bangladesh.