Due to its low cost, most large cargo vessels are powered by bunker fuel which contains higher sulphur levels than diesel.
The ship originally burned heavy bunker fuel.
The vessel suffered a mechanical problem after seawater got into its bunker fuel.
The captain had sufficient bunker fuel to get his ship to Brisbane at her most economical speed, but no further.
Both ran their trials on a mix of algal oil - between 7% and 100% - and conventional bunker fuel.
The price of "bunker" fuel, which powers many cruise ships, rose 30 percent in the past three months alone.
A private investigation was initiated and a system for the use of heavy oil as bunker fuel was revealed.
The worst polluters are the large container ships that burn heavy bunker fuel.
Now, most ships have an engine using a slightly refined type of petroleum called bunker fuel.
The stations carry the following fuel types: petrol, gas oil, bunker fuel and diesel.