Equilibrium - a ballast-free crude oil tanker

Abstract

Equilibrium is the name of a ballast-free oil tanker concept invented by naval architects at Det Norske Veritas (DNV) and further developed in this master’s thesis at the Norwegian University of Science and Technology (NTNU).

The task is to analyze the conceptual design work done by DNV and further develop the concept. The main focus is on a cost comparison with a conventional tanker with a deadweight equal to Equilibrium and a conventional VLCC. The cost comparison focuses only on the costs that are expected to be different in these designs: Building costs, fuel costs and the cost of ballast equipment and operation. This comparison serves as an indicator of the profitability and thereby feasibility of the design.

A trapezoid shaped hull and longitudinal cargo boundaries make Equilibrium independent of ballast in transit and during loading and discharging. The ballast-free return legs result in a significant annual saving of fuel and CO2 emissions. This is Equilibrium’s main advantage  over a conventional design.

Equilibrium’s main disadvantage is that the cargo capacity is about 60 000 tons lower than on a conventional VLCC. This again affects the cost efficiency of the ship. Since Equilibrium is bigger than the Suezmax limitations, the VLCC is regarded as the main competitor.

A cost-efficiency index of the relevant life cycle costs over 10 years divided by the amount of cargo delivered in the same period, shows that Equilibrium is a profitable design. Further analyses needs to be done on the ship’s sea keeping abilities with special attention to accelerations in roll motion. The proposed Equilibrium design can compete against existing tankers on both cost-benefit and environmental impact.