Hull form optimization

In general, optimization means finding the best solution with an unlimited number of variables. Ship design is closely linked to optimization and in general the owner has three options when acquiring a new-build when it comes to hull form optimization: accept standard design, modify existing design or develop a new design. The two last options involve optimization for specific service conditions, modification to the forebody and stern shape design and optimization of the vessel hull. Minimizing hull resistance will lead to lower fuel consumption.

While main particulars are generally well optimized across shipyards, there is significant variance in the degree of hull form and propeller optimization. A comprehensive series of model tests and computational fluid dynamic (CFD) assessments are needed to fully optimize a hull form. Shipyards tend to optimize around the specified design draft and speed, while giving less attention to the efficiency at the ballast draft, and little or no attention is paid to partial load conditions.

Applicability and assumptions

Computational fluid dynamic (CFD) assessments are needed to fully optimize a hull form, source: DNV GL

Hull form optimization can be applied to all vessel types and ages. There is larger potential for fuel saving where the expected operating profile differs from the standard design. A CFD analysis typically includes three or more iterations of lines refinement and should be carried out with multiple trims and drafts.

Cost of implementation

When considering hull form optimization, it is beneficial to include sister vessels in the CFD analysis to reduce the cost for the fleet. The cost of a full CFD analysis to find an optimum hull form to one specific vessel will be in the range of $150,000 to $500,000 (USD).

Reduction potential

The reduction potential is dependent on vessel size, segment, operation profile and trading areas. A reduction of 4% to 8% on main engine fuel consumption is likely.

Other References

1. Hull form optimization / Overview over most recent hull form optimization related papers from Maritime Research Institute Netherlands