How does mazut compare with other marine fuel oils?

How does early twentieth-century engine oil compare with Russian mazut?

The former is considered substantially better; mazut receives a strongly negative assessment of its quality and handling.

The comparison receives a strongly negative answer about mazut's handling and quality. Heavy ship fuel already needs warming before it flows readily, and mazut is described as an especially difficult case. Exaggerated comparisons with rocks and road material convey that criticism. Those jokes express the severity of the criticism rather than supplying a measured fuel specification.