Two black tanks
One rounded, one more cylindrical. Design differences due to fashion or
function? The round one has less surface/volume. The cylindrical one lets you cram more tank volume into the same building volume.
After the whaling operations ceased, these tanks were used for boiling basking shark liver oil.
These tanks are also seen in the background of a fire drill.
More or less similar tanks can be seen at Hector.
(Requires Google Earth)