Wave Added Resistance

By Patrick Hooijmans
Thursday, September 20, 2012

MARIN Unravels Secrets of Wave Added Resistance

Model tests for the evaluation of ship designs should not only be performed in calm water but also in waves. MARIN’s new Depressurized Wave Basin (DWB) helps unravel some of the mysteries of wave added resistance.
A ship is usually designed with a focus on its performance in calm water. However, operational conditions should be taken into account, including added resistance due to waves because it is an important factor in the economical performance of a ship.
The sustained speed in storm conditions should be investigated but also the power increase in typical service conditions. And with the trend for an increasing ship size, the latter becomes even more important. In addition, upcoming regulations such as EEDI require a very careful correction for the added resistance during speed trials.
Using large ship models in a 240x18x8 m towing tank can make the difference when trying to understand the secrets of wave added resistance. In the DWB a large ship model of a Very Large Container Ship of about 350 m for instance, can be tested at a model scale ratio of 1 to 30.
In our Seakeeping and Maneuvering Basin (SMB) the scale ratio typically doubles, which means that a 1.5 m wave for the ship would require a 2.5 cm wave in the SMB and a 5 cm wave in the DWB. This increase, in combination with increased measurement accuracy, improves the prediction of wave added resistance in typical service conditions.
A further benefit of the DWB is that only one large ship model is used to perform calm water resistance and propulsion tests, cavitation observations, hull pressure measurements and wave added resistance tests for mild to severe weather conditions. When well prepared, all the tests can be conducted within one week. A ship model can be chosen with large propeller models with a diameter of about 300mm, reducing significant scale effects on propeller blade cavitation and propeller thrust and torque. This provides a high level of accuracy when measuring for instance the wave added resistance. In this way MARIN expects to unveil some of the secrets of wave added resistance.

The Author
Patrick Hooijmans is project manager at the Ships department of MARIN, the Maritime Research Institute Netherlands. MARIN offers simulation, model testing, full-scale measurements and training programs, to the shipbuilding and offshore industry and governments.
Email: p.hooijmans@marin.nl

(As published in the August 2012 edition of Maritime Reporter - www.marinelink.com)

Maritime Today

The Maritime Industry's original and most viewed E-News Service

Maritime Reporter November 2015 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds


Bill on Danish Maritime Planning Submitted

The bill is to form the basis of a maritime planning act intended to promote economic growth and development of sea areas. The Danish Maritime Authority is to head the work.

Seaspan Implements ECO Insight solution

Seaspan Ship Management Ltd. will implement the DNV GL fleet performance management solution ECO Insight to improve their fleet monitoring. ECO Insight will

New Appointments at Becker Marine Systems USA

Becker Marine Systems USA continues growth in North America. Becker Marine Systems, the leader in rudder technology and the inventor of the Becker Mewis Duct

Naval Architecture

Henriksen Unveils Strongest SOLAS Boat Lifting Hook

H Henriksen of Norway has received SOLAS certification for a new off-load single-point boat lifting hook capable of holding up to 22.5-tonnes. The quick release

Escort Tug Launched for Bay-Houston Towing

Eastern Shipbuilding Group, Inc. announced the launch of the Escort Tug H. DOUGLAS M (Hull 236) for Bay-Houston Towing Company on November 17, 2015. This series of Robert Allan, LTD.

Nakilat Damen Shipyards Qatar JV is 5

On 23 November 2015, Nakilat Damen Shipyards Qatar celebrated its first 5 years of operation. With 40 vessels delivered or under construction, the yard has proven

Maritime Contracts Maritime Security Maritime Standards Navigation Offshore Oil Pipelines Salvage Ship Electronics Ship Simulators Winch
rss | archive | history | articles | privacy | 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: 0.0957 sec (10 req/sec)