0
Ocean Engineering

Wave-Induced Motions of Gas Cat: A Novel Catamaran for Gas Processing and Offloading

[+] Author and Article Information
Giles Thomas

 Australian Maritime College University of Tasmania, Australiagiles@amc.edu.au

Alexandra Ford, Landon Kibby, Jonathan Binns

 Australian Maritime College University of Tasmania, Australia

Ian Finnie

 WA ERA, Perth Western Australia, Australia

Neil Kavanagh

 Woodside Energy, Perth Western Australia, Australia

J. Offshore Mech. Arct. Eng 134(2), 021102 (Dec 02, 2011) (7 pages) doi:10.1115/1.4004957 History: Received July 27, 2009; Revised February 09, 2010; Published December 02, 2011; Online December 02, 2011

The preliminary development of the novel concept of using a large catamaran, known as Gas Cat, as a floating natural gas processing and offloading facility is outlined. The proposed system is based on two ship-shaped hulls joined by a spanning superstructure. For off-loading purposes a carrier may dock with or be tethered to the catamaran. A concept design has been developed based on two retrofitted VLCCs allowing for the processing and storage of 1 × 106 bbls of condensate and approximately 240,000 m3 of liquefied natural gas. A key aspect of the development of this concept is the accurate estimation of the motions of the catamaran in a variety of operational scenarios. Model experiments were conducted in the Model Test Basin of the Australian Maritime College using a 1:78 scale model of two full-form hulls converted into a catamaran configuration. Tests were conducted in head, beam, and oblique seas for two hull spacings and a range of wave heights. The experimental results show that for the range of wave conditions tested good linearity of the motions can be expected with respect to wave height. An increase in demihull separation was found to significantly reduce the sway, heave, and roll motions in beam seas. However, a change in demihull separation had little influence on the motions in oblique seas. A change in heading angle from head seas to beam seas significantly increased the sway, heave, and roll motions while reducing pitch motions. Bow quartering seas were seen to be the worst heading angle for yaw. The results from the experiments allowed the expected motions of the Gas Cat to be determined in extreme weather conditions.

Copyright © 2012 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Gas Cat preliminary design and layout

Grahic Jump Location
Figure 2

Gas Cat model during testing viewed from the bow. The active infrared markers can be seen as white spheres. The port hull contains a 6-component force balance used to measure coupling loads.

Grahic Jump Location
Figure 3

Sample raw roll data (condition 6)

Grahic Jump Location
Figure 4

Nondimensional heave, pitch, and roll, conditions 1 and 2

Grahic Jump Location
Figure 5

Nondimensional surge, sway, and yaw, conditions 1 and 2

Grahic Jump Location
Figure 6

Nondimensional heave, pitch, and roll, conditions 6, 7, and 8

Grahic Jump Location
Figure 7

Nondimensional surge, sway, and yaw, conditions 6, 7, and 8

Grahic Jump Location
Figure 8

Nondimensional heave, pitch, and roll, conditions 2 and 3

Grahic Jump Location
Figure 9

Nondimensional surge, sway, and yaw, conditions 2 and 3

Grahic Jump Location
Figure 10

Nondimensional heave, pitch, and roll, conditions 4 and 5

Grahic Jump Location
Figure 11

Nondimensional surge, sway, and yaw, conditions 4 and 5

Grahic Jump Location
Figure 12

Nondimensional surge for varying wave heading angle (conditions 3, 5, and 7)

Grahic Jump Location
Figure 13

Nondimensional sway for varying wave heading angle (conditions 3, 5, and 7)

Grahic Jump Location
Figure 14

Nondimensional heave for varying wave heading angle (conditions 3, 5, and 7)

Grahic Jump Location
Figure 15

Nondimensional pitch for varying wave heading angle (conditions 3, 5, and 7)

Grahic Jump Location
Figure 16

Nondimensional roll for varying wave heading angle (conditions 3, 5, and 7)

Grahic Jump Location
Figure 17

Nondimensional yaw for varying wave heading angle (conditions 3, 5, and 7)

Grahic Jump Location
Figure 18

Extreme motion amplitudes that should not be exceeded in 24 h exposure with 99% confidence in 10,000 year return period storm

Grahic Jump Location
Figure 19

Render of the Gas Cat concept

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In