Contra-Rotating Propellors: New System Prediction Software

Press Release
Sunday, February 17, 2013

New features for the industry-standard resistance and propulsion software, HydroComp's NavCad.

Many contemporary marine vehicles are being outfitted with contra-rotating propellers (CRP), and naval architects need the ability to model the performance of CRP systems – a capability that has been lacking until now.

As part of its ongoing internal R&D program, HydroComp, Inc. has just deployed a new CRP system analysis module into HydroComp NavCad®, the industry-standard software for the prediction and analysis of vessel speed and power performance.

Published comparisons of the efficiency between standard fixed-pitch propellers (FPP) and CRP propellers typically indicate that CRPs are between 3% and 10% more efficient. It is often presumed that the efficiency gains of a CRP are due solely to recovery of energy lost in the rotational flow of a single propeller.

While recovery of rotational energy is partly responsible for the efficiency gains with a CRP, much of the gain actually occurs due to improved inflow and the reduction in propeller blade loading (with its corresponding change in RPM and blade area ratio).

HydroComp evaluated an extensive catalog of published studies that made direct comparison between FPP and CRP propellers. From the results of this evaluation, a new CRP performance prediction method was developed around a “system-level” model using only the representative definition of one propeller in the set to determine the overall system performance.

The intent of the new CRP method is to reasonably predict the overall performance of a CRP “system”, and is not intended to provide a means to design or size the specific details of the blade sets.

HydroComp’s new CRP (Simple) model includes proper consideration of:

• Thrust and torque division for proper individual blade loading.
• Reduction in loading due accelerated induced velocities.
• Increased efficiency due to improved inflow and recovery of rotational losses 
• Reduced hull efficiency due to rudder interaction. 

 

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

Technology

Port St. John to Install KleinPort System

Klein Systems Group Ltd. announced today that it has entered into an agreement to install the KleinPort Port Management Information System at Port Saint John, New Brunswick.

ST Marine Celebrates Naming of Vessels

Singapore Technologies Marine Ltd (ST Marine), the marine arm of Singapore Technologies Engineering Ltd (ST Engineering), held the Naming Ceremony today for the second Patrol Vessel (PV),

ABG Ties Up with GTT for LNG Technology

ABG Shipyard Ltd has tied up with Gaztransport and Technigaz (GTT) of France for the maritime transportation and storage of liquefied natural gas (LNG), reports Livemint.

Marine Propulsion

Palfinger Chooses NAMJet Waterjets

Netherlands-based Palfinger Boats has launched the first of two Damen-designed FRSQ 1200 fast-rescue/oil response vessels.   Built in Harderwijk, Netherlands,

ABG Ties Up with GTT for LNG Technology

ABG Shipyard Ltd has tied up with Gaztransport and Technigaz (GTT) of France for the maritime transportation and storage of liquefied natural gas (LNG), reports Livemint.

Methanol Powered Ferry Launched in Baltic Sea

Swedish ferry operator Stena Line has announced that it has converted the Stena Germanica to run on methanol, an industry first.   The company spent $24 million on converting the ship to methanol.

Software Solutions

Port St. John to Install KleinPort System

Klein Systems Group Ltd. announced today that it has entered into an agreement to install the KleinPort Port Management Information System at Port Saint John, New Brunswick.

Maersk to Install Transas ECDIS on 100 Vessels

Maersk Line, the world's largest container company, has selected Transas Marine for ECDIS implementation on more than 100 vessels, Transas announced today. The

KVH Outlines Ship-to-Shore Connectivity

The next generation of connectivity between ship and shore will be dominated by the development of applications to help ship owners and managers reduce costs by enhancing operational efficiency,

 
 
Maritime Contracts Maritime Standards Navigation Pod Propulsion Port Authority Ship Electronics Ship Repair Ship Simulators 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: 0.1791 sec (6 req/sec)