General HydroStatics
Ship Stability Software
Command of the Week
(New or interesting aspects of GHS that you may not know about)

(Requires GHS version 16.02 or later with SeaKeeping Module)

Typically, FV.GF or TANKER.GF steal the show, and very little attention is given to the humble and hardworking BARGE.GF. We thought it was time to highlight one thing BARGE.GF does very well: carry ISO containers.

It is expected that a scaled-up version of BARGE.GF will be hauling sixty, 40-foot ISO containers on its way up to Alaska. The containers are to be loaded in a 5x6x2 arrangement as shown below.

The expected loading condition is given by the STATUS report shown. Note that the lightship gyradius is specified and each individal container gyradius was included using the ADD /BOX parameter.

BARGE.GF will be transiting some distance offshore, so a Narrow-Band Bretschneider wave spectrum with a characteristic period of 12.0 seconds and a significant wave height of 7.2 feet is specified:

 wave (spe) BR 12.0, 7.2, N

In the region of interest, the barge will be transiting at a speed of 6 knots with an expected wave heading of 135 degrees. The fastening points for container #1 and #60 are defined by critical points (1) through (8), so we include these points in the seakeeping analysis. We are interested in the most probable extreme acceleration response amplitudes in a 24 hour period, so we also specify a confidence level of 99% over the desired period and include a summary table of the accelerations.

 sea /head:135 /speed:6 /crt:1,2,...,8 /samp:30 /conf:99,24 /sum:A /gu

After running SEAKEEPING with the stated parameters, the resulting Absolute Response Summary table is given below. The surge, sway, and heave (x, y, and z direction) translational acceleration amplitudes are summarized for each fastening point. The rotational accelerations are also given for completeness.

Finally, BARGE.GF is getting some well-deserved attention. And judging from the accelerations, it looks like all sixty containers will be onboard when BARGE.GF reaches its destination.

Questions, comments, or requests?
Contact Creative Systems, Inc.

USA phone: 360-385-6212 Fax: 360-385-6213
Office hours: 7:00 am - 4:00 pm Pacific Time, Monday - Friday

Mailing address:
PO Box 1910
Port Townsend, WA 98368 USA

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