oilberg

plural oilbergs

1. informalA supertanker that transports oil.

   That is a lot of ship, about the the^([sic]) size of big tankers before they grew so rapidly to become supers, mammoths and oilbergs.

   1973, Jeffrey Potter, Disaster by Oil, page 46

   1 more example

   With the advent of supertankers — aptly nicknamed "oilbergs" — the danger increases that 300,000 tons or more may be dumped in a single mishap.

   1970, LIFE, volume 68, number 8, page 29