APL Saves $30M/Year through Hull Optimization

by Cosmin Ciortan, DNV
Tuesday, October 29, 2013
New hull design (image courtesy DNV).

In connection with an order of a series of 10 new 13,800 TEU container vessels from the world’s largest shipbuilding company Hyundai Heavy Industries (HHI), the global container transportation company APL requested DNV Maritime Advisory to cooperate with the shipyard to ensure superior hull efficiency of the vessels.

Optimizing the Hydrodynamic Performance of a Vessel
Ships used to be optimized for the design point (i.e. to give the best performance at the design draft and speed); however, the ship seldom sails in that condition. As a result, APL asked for a different kind of optimization to be performed, this time targeting various speed-draft combinations as described in the operating profile.

The overall hydrodynamic performance of a vessel is directly connected to the resistance and propulsive efficiency. The resistance is influenced by the hull shape, the wetted surface area and the configuration of appendages, while the propulsive efficiency is influenced by the propeller open water characteristics and the interaction between hull and propeller. The performance depends on the variation of operating conditions, i.e. vessel speed, draft and trim.

Vessels have traditionally been optimized for a single condition, normally the contract speed at design draft. With the help of state-of-the-art Computational Fluid Dynamics (CFD) tools and modern computers it is now possible to optimize a vessel for various conditions in which the vessel will be trading.

DNV Maritime Advisory has worked with hull optimization for several years, serving shipowners, shipyards and designers with valuable advice during the design process. DNV’s experts have extensive relevant experience within ship hydrodynamics and energy efficiency, applied to numerous vessel types and sizes including the major segments: tankers, bulk carriers and container vessels.

The Optimization Process

A typical project for hydrodynamic hull optimization may include:
•    Establishing a close dialog between DNV, the shipowner and the shipyard
•    Defining a realistic operating profile
•    Discussing and combining DNV’s design ideas with the yard’s design philosophy to obtain an optimal hull in both a hydrodynamic and building perspective
•    Optimizing the hull forebody based on the operating profile
•    Optimizing the hull aftbody to improve the propulsive efficiency, including consideration on propeller and machinery configuration
•    Assessing the Energy Efficient Design Index (EEDI)
•    Supporting during preparation and attending the towing tank model tests

The delivered value for the ship owner and the shipyard is increased confidence in the hydrodynamic performance of the hull. Typically, considerably improved fuel efficiency and reduced gas emissions are achieved throughout the vessel’s lifetime. In this specific case, the scope of work included:
•    Establishing a weighing matrix for the vessel’s relevant operating profile
•    Optimizing the hull forebody and aftbody (shoulders, bulb, transom stern height, etc.) based on the operating profile
•    Analyzing the wake and propulsion efficiency
•    Predicting the speed – power and fuel oil consumption curves
•    Assessing the preliminary EEDI
•    Attending the towing tank model tests

All simulations of resistance and wake assessment were performed using STAR-CCM+. According to OlavRognebakke, head of ship hydrodynamics and stability at DNV, it is the availability of powerful CFD tools such as STAR-CCM+, combined with the expertise of highly qualified staff which made it possible to enhance Hyundai’s already very good design.

Outcome of the assessment

The hull was optimized for five different design points (different speed-draft combinations). The aft part was optimized for maximum propeller efficiency. In addition, the bulb was lowered to be efficient at lower drafts too. While this solution may result in a marginal penalty at the original design condition, the aim was to optimize the hull for a range of operating conditions. Instead of a design speed of 25 knots, the new vessels were optimized for lower speeds, with a top speed of 23 knots, following the “slow steaming” trend observed in the last years. The overall improvement in energy efficiency was 36%.

Conclusion
By working closely and keeping a continuous dialogue with APL and HHI, DNV ensured that the best ideas and results were combined into the final hull design. It was estimated that the optimized hull will result in annual fuel savings of about $3 million per ship, which amounts to annual savings of $30 million for the whole fleet. These achievements provided positive market attention and ensured improved market positions for both the ship owner and the shipyard. Finally, the cost of the service provided by DNV Maritime Advisory is negligible compared with the savings achievable through improved fuel efficiency. DNV, which is an independent foundation, has entrusted all commercial rights to Hyundai Heavy Industries.

Facts
DNV Maritime Advisory runs fully viscous and potential flow CFD simulations at full scale. STAR-CCM+ and Shipflow are used on a computational cluster with more than 600 CPUs. Several design applications are used, including MaxSurf, NAPA, Rhinoceros, HDef and ShipX. DNV has been carrying out hydrodynamics hull optimization projects in cooperation with major ship owners, world leading shipyards and design offices. Previous projects covered several container vessels ranging from 1,600 to 14,000 TEU, Aframax and Suezmax tankers, bulk carriers ranging from 38,000 to 206,000 dwt and offshore supply vessels.

(As published in the October 2013 edition of Maritime Reporter & Engineering News - www.marinelink.com)

Maritime Reporter September 2014 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Shipbuilding

Water-cooled WGM Motors From WEG

WEG, a supplier of drive technology, introduced its water-cooled WGM motors to the shipbuilding industry for the first time at SMM 2014. The WGM water-cooled induction motors are compact,

Henderson, Hanes & Associates Opens Doors in Miami

Ocean Engineering/ Naval Architecture Firm Brings Innovation to the Mega Yacht Community The Miami-based ocean engineering and naval architecture firm of Henderson & Associates, Inc.

Austal Launches Trenton (JHSV 5)

Second Joint High Speed Vessel to be launched at Austal in 2014 On September 30, 2014, Austal USA successfully completed the launch process of Trenton (JHSV

Ship Repair & Conversion

Henderson, Hanes & Associates Opens Doors in Miami

Ocean Engineering/ Naval Architecture Firm Brings Innovation to the Mega Yacht Community The Miami-based ocean engineering and naval architecture firm of Henderson & Associates, Inc.

Scanjet Secures 30-ship Tank Management Order

Scanjet Group has followed up its Tank Management order from Stolt-Nielsen with a series of contracts for its ITAMA Intelligent Tank Management concept including Tankcleaning,

Industry Professionals to Speak at ShipConstructor Conference

The speakers representing various companies at next week's SSI Americas ShipConstructor User Conference, October 7-9, 2014 in Mobile, Alabama, demonstrate SSI's

Container Ships

Chinese Manufacturing Expansion Affects Shipping Demand

The expansion of the Chinese Manufacturing Industry continued in September at unchanged pace as compared to the month before, BIMCO reports. The manufacturing industry

Going Big for Sustainability

Orkot Marine Bearings, developed and manufactured by Trelleborg Sealing Solutions, contribute to the build of the world’s largest and most efficient containerships,

MOL Restructures Asia to S. Africa Service

Mitsui O.S.K. Lines, Ltd. (MOL) announced the restructuring of its existing Asia to South Africa liner services into two direct loops. One service will call South China,

Naval Architecture

Henderson, Hanes & Associates Opens Doors in Miami

Ocean Engineering/ Naval Architecture Firm Brings Innovation to the Mega Yacht Community The Miami-based ocean engineering and naval architecture firm of Henderson & Associates, Inc.

MAN Propulsion Packages for New Trawler Series

Orders for five fresh-fish trawlers feature two different ship designs and MAN 6L27/38 engines and aft-ship equipment Icelandic owners, HB Grandi, Vinnslustodin hf.

General Dynamics takes Rudy deLeon on Board

The board of directors of General Dynamics has elected Rudy deLeon to be a director of the corporation, effective September 30, 2014. DeLeon is a senior

News

Livorsi Launches New Throttle Lineup

Livorsi Marine introduced the all new Platinum Series throttles, which they say are designed to be more ergonomically comfortable to the operator while being lighter

Henderson, Hanes & Associates Opens Doors in Miami

Ocean Engineering/ Naval Architecture Firm Brings Innovation to the Mega Yacht Community The Miami-based ocean engineering and naval architecture firm of Henderson & Associates, Inc.

Austal Launches Trenton (JHSV 5)

Second Joint High Speed Vessel to be launched at Austal in 2014 On September 30, 2014, Austal USA successfully completed the launch process of Trenton (JHSV

Vessels

Austal Launches Trenton (JHSV 5)

Second Joint High Speed Vessel to be launched at Austal in 2014 On September 30, 2014, Austal USA successfully completed the launch process of Trenton (JHSV

DOF Installer Sells Offshore Vessel

DOF Subsea AS subsidiary, DOF Installer ASA, reported the sale of one of its three sister ships, an anchor handling tug supply (AHTS) vessel, to an international buyer.

Chinese Manufacturing Expansion Affects Shipping Demand

The expansion of the Chinese Manufacturing Industry continued in September at unchanged pace as compared to the month before, BIMCO reports. The manufacturing industry

Software Solutions

BCG Upgrades Virtual GMDSS Simulator

Buffalo Computer Graphics (BCG) Inc. released an updated version of its Virtual Global Maritime Distress and Safety System (VGMDSS) Simulation software. BCG’s VGMDSS

General Dynamics takes Rudy deLeon on Board

The board of directors of General Dynamics has elected Rudy deLeon to be a director of the corporation, effective September 30, 2014. DeLeon is a senior

New Simulation Tool for Collision Reconstruction

BMT ARGOSS and BMT Surveys, subsidiaries of BMT Group Ltd, the international design, engineering and risk management consultancy, announced an innovative new service

 
 
Maritime Careers / Shipboard Positions Naval Architecture Navigation Pipelines Pod Propulsion Salvage Ship Electronics Ship Repair Sonar Winch
rss | archive | history | articles | privacy | terms and conditions | contributors | top maritime news | about us | copyright | maritime magazines
maritime security news | shipbuilding news | maritime industry | shipping news | maritime reporting | workboats news | ship design | maritime business

Time taken: 0.1714 sec (6 req/sec)