Bulbous bow pays off in a year

The findings came from a DNV optimisation project with Hyundai Merchant Marine (HMM) and Daewoo Shipbuilding and Marine Engineering subsidiary DSEC, which saw the Korean yard retrofit an optimised bulbous bow to a five year old, 8,600 teu HMM container ship.

The retrofit increased fuel efficiency by 5%, exceeding predicted gain from computational fluid dynamics models.

Affectionately known as a nose job, bulbous bow optimisation replaces a bow designed for faster operating speeds with one better suited to a vessel's actual operating speed and draft, adjusting to current market realities such as slow steaming.

For the HMM ship the design speed was 27 knots and the vessel currently operates between 15 and 18 knots, rendering its original bulbous bow inefficient.

Costing around $625,000 in total and completed within a routine dry-docking period of two weeks, the refit did not add any extra downtime for the vessel and will repay the initial investment within one year at current bunker prices.

DSEC said, "after we got the results of this modification, we gave the information to some owners who built container vessels at DSME and several owners are interested and have requested proposals."