Close

DLBA UNIVERSITY

Low speed efficiency, high sprint capability - it's all in the hull

JUNE 26, 2019

The performance of three different shaped hulls was evaluated by experiments and computations to identify a hull form that provides low calm water resistance at cruise speed while remaining dynamically stable at high speed. The target cruise speed was at a length Froude number of 0.45, and the target high speed was at a length Froude number of 1.0.

 

The three hybrid hulls utilized a common round bilge after body shape derived from the NPL systematic series mated to different bow shapes:

Hull #1- Double Chine

Hull #2- Round Bottom with Spray Rail

Hull #3- Single Chine

Low speed efficiency, high sprint capability - it's all in the hull​

The 1:20 model-scale experiments were performed at the SSPA Towing Tank to evaluate the calm water resistance and dynamic stability characteristics of the three hulls. Two displacements and up to three Longitudinal Center of Gravity positions were evaluated for each model.


A computational study using STAR-CD, a Reynolds Averaged Navier-Stokes solver, was performed to investigate a limited number of the test conditions evaluated at SSPA. The computations included time-accurate runs designed to duplicate the dynamic stability testing methodology utilized in the experiments.


Model #3- Single Chine was found to represent the lowest drag of the candidate hull forms at cruise speed while retaining dynamic stability at high speed. The calm water resistance of this hybrid hull shape at cruise speed was found to be within 8.5% of a purely round bilge hull form as represented by the NPL systematic series.

 

In case you would like to receive the full paper, or discuss about this subject, please contact Jeffrey Bowles.

Low speed efficiency, high sprint capability - it's all in the hull​

Share this article online:

Share on facebook
Share on linkedin
Share on twitter
Share on whatsapp
HOW CAN WE HELP YOU?
FEEL FREE TO CONTACT US

DLBA Naval Architects

860 Greenbrier Circle, Suite 201  Chesapeake, Virginia 23320 USA

Phone: 757-545-3700  |  Fax: 757-545-8227  | dlba@gibbscox.com

STAY UPDATED

SIGN UP FOR OUR NEWSLETTER

Keep your finger on the pulse of the latest points of focus in naval architecture and engineering: subscribe to DLBA’s concise monthly newsletter. Within it, we briefly describe and picture our latest projects and concepts. We encourage feedback and seek to have our newsletter spark conversation regarding potential collaborations and further advancements as we share our passion for the industry.