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General HydroStatics
Ship Stability Software |
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Command of the Week
(New or interesting aspects of GHS that you may not know about) |
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Loading Software (GLM review)
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GLM (GHS Load Monitor) is our on-board Trim and Stability software based on GHS.
It evaluates loading conditions for compliance with stability and strength requirements. Depending on the complexity of the vessel, a particular GLM may be as simple as a lookup against a curve of maximum VCG values or as complex as damage cases with cranes lifting heavy loads over the side with or without damage.
GLM uses the GHS model of the ship, and all calculations are performed using the same engine that you've trusted for years. Therefore, you can expect the results from the on-board version to match your approved T&S booklet. The model of the ship and tanks gives accurate results for a wide range of heel and trim angles and permits flooding, longitudinal strength, and even grounding calculations. This is far superior to software that uses pre-calculated data. GLM has been evaluated by and received approval from several Class authorities. This is unusual: We put the GLM configuration tools in the hands of naval architects and let them work with their clients to optimize the configuration. The result is pleasing to vessel owners and operators because the communication channel is short and responsive. It also pleases naval architects because they can sell the whole package to their clients, including the cost of their configuration process. The GLM configuration wizard presents a multitude of options, some of which are discussed here. The configured GLM software for a particular vessel can be installed on any number of computers without additional licensing fees. And the GLM licensing fee to begin with is much less than a GHS license costs because it is locked to the geometry of one vessel. What does GLM look like to the vessel operator? If Load Editor is in your GHS configuration, you're already familiar with it. Weight entry is by means of a spreadsheet-type interface. In the configuration you will typically supply the GLM with a set of initial weights added to light ship that would be expected aboard the vessel. The operator can of course add or remove weights as necessary to match the current condition. The Tanks tab lets the operator specify contents and load for each tank. Tank soundings can be entered manually, or if Sensor Interface is configured, tank loads will be set automatically according to the data from the ship's tank level sensors. In the rare occasion that a vessel's tanks can be rearranged, the GLM supports switching between different tank configurations easily. |
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| As a reality check for a condition, the operator can enter the current draft readings into the Verify Drafts dialog, which is shown below. This is a simple deadweight survey where the weight accounting in the condition is compared against the immersed volume predicted by the drafts and the difference is reported as either a WEIGHT EXCESS or a WEIGHT NEEDED. The amount of the difference and the location are provided to aid the crew in tracking down the unaccounted for objects on the vessel. |
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| A means of saving and naming each condition is provided as a way to retrieve them. Once a condition is finalized, the Reports button provides all the options needed to record the evaluation of the condition. |
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So, if you are a naval architect, consider configuring GLMs for your clients. If you are a vessel operator, ask your naval architect about a GHS Load Monitor for your vessels.
Note: The ship depicted above is not one of the hundreds of ships that have GLM installed aboard: it is simple geometry that we put together for demonstrating GLM. While we have all the actual GLM models in our files, they are the property of our customers, and we do not share them with anyone else. |
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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 Click here for an index to this and previous COWs |