Twenty sixth day of the voyage; third day of the Caribbean crossing, threading our way through the Bahamas.
What do walnut shells and heavy black fuel oil, barely refined from crude, have in common? They both go through massive two-stroke ship’s engines. The fuel oil is obvious: so thick it needs to be warmed in colder climes before it can be used, they talk not of litres but of tonnes. And at about the 80 revs a minute needed to sustain a speedier vessel like this one at 20 knots, the engine burns about 100 tonnes a day. A quick calculation: with about three days stoppage for six ports in a 37 day voyage, that is 3400 tonnes for our voyage. All of which does not include diesel for the four generators and fuel oil heater.
But walnut shells? A few bucket-loads thrown into the engines every couple of weeks clears the pipes. You know when, for suddenly it will be raining black pieces of ash about the size of those shells.