Maximising efficiency and minimising cost in high speed craft

To reduce the capital cost of a RORO vessel the minimum structural material weight is desired which would result in a fairly short vessel. In conflict with this is that to reduce operating costs a much longer vessel is normally desired to allow the vessel to operate at low Froude number so resistance is mainly frictional. However, the resistance effect can be more than offset by reduced displacement for a given deadweight. The conventional steel mono-hull RORO vessel is generally very long for this reason but incurs high capital cost as a consequence. Thus the alternative to a long mono-hull RORO is a much shorter but wider wave piercing catamaran that can have both low capital and operating costs. This opens up the possibility of operating at medium speeds where the high overall efficiency of the catamaran hull form and structure enables operation at medium speeds more efficiently than a conventional RORO mono-hull vessel. This paper explores how a large wave-piercing catamaran can be optimised to operate with high deadweight, high efficiency and high manoeuvrability.