Aristotle Onassis of his fleet, while having trouble managing their own fleets, which operated under US flags and thus at high cost. The high profitability of the Onassis fleet has been attributed in large part to his disregard for standards that normally govern international shipping. For example, after his Liberian registered tanker SS Arrow ran aground and spilled oil into Chedabucto Bay in 1970, still the most significant oil spill off Canada’s East Coast (about 25% of the amount spilled by the Exxon Valdez in Alaska in 1989), there was a Commission of Inquiry. Led by Dr Patrick McTaggart-Cowan, executive director of
Architecture of the oil tanker a mid-deck design overcomes this by eliminating the double-bottom compartments that are void with air. Since the density of seawater is greater than that of oil, water comes into the tanks instead of oil escaping out, and rather than spilling, oil is vented upwards into overflow tanks. If the "Exxon Valdez" had been a Mid-Deck ship, she would have spilled very little oil. A variation on the Mid-Deck Tanker is the Coulombi Egg Tanker, which was approved by IMO as an alternative to the double hull concept. The design consists of a series of centre and wing tanks that are