Tosca

Bulbous Bow Retrofit of CMA CGM Tosca 

CMA CGM Tosca is an 8500 TEU container ship, part of the Otello Series. With rising gas prices and large changes in operating profile, CMA CGM decided to perform a bulbous bow parametric optimization in order to reduce ship fuel consumption.
   
Bureau Veritas Solutions Marine & Offshore was contracted with the objective of reducing ship power for a given operational profile of 17 conditions combining ship speed and draft.

Initial bulbous bow

Initial bulbous bow

Optimized bulbous bow

Optimized bulbous bow

Over 50 bulbous bows were automatically generated with our parametric hull modeler, OptNav. The directions and amplitudes were defined with CMA CGM in order to respect all given constraints (ship volume, stability rules, architectural and construction constraints). The hull forms were then evaluated using the CFD free surface Navier Stokes solver, ICARE. The main particularity of this project was that overall 850 RANSE-CFD computations were performed (50 bulbous bows x 17 operating points) in only a few days.

deformations

CFD results allowed CMA CGM to identify optimal designs with huge resistance gains in operational conditions as compared to the initial hull form. The pictures show the free surface elevation of initial and optimal designs for a selected condition, and a histogram of gains obtained for each condition of the operational profile.

resistance

Resistance gains for each operational condition

Comparison of initial and optimized bulb performances

Comparison of initial and optimized bulb performances