HECSALV Charles Dorger Fall 2009
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Contents 1 Importing Your Model into HECSALV
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2 Tables 2.1 Hydrostatic Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Bonjean Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Cross Curves Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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3 Compartments
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4 Floodable Length
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5 Damage Stability
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6 Conclusion
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Today, we will be covering how to use HECSALV. HECSALV is a computer program specializing in Naval Architecture design work. Some feature such as damage stability and floodable length is easier to use in HECSALV rather than in Maxsurf. This tutorial will cover how to import your model. 1
Importing Your Model into HECSALV
We will start with the R/V Lemuria’s Hull:
Figure 1: R/V Lemuria Hull Select the hull and then choose Tools/Attach GHS Data. GHS data is another way of importing hull forms. It captures the shape of the hull by either using a default or user defined number of sections.
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Figure 2: Tools Menu A menu will then appear. Start by choose Hull Items.
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Figure 3: Attach GHS Data Window Then select Add Part and select your hull. This should then appear:
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Figure 4: GHS Data You will notice that pink stations have appeared. Nota Bene Sometimes only half of the hull stations will be selected. This is fine, since most hulls are symmetric and HECSALV should recognize that. As a personal preference, I choose the centerline option. Nota Bene Notice how the bow is more pink than the stern. This is because the bow is more defined and takes more stations to correctly define it. Now you can leave the default selection, or you can define how many stations you want to use. Select Edit Shape and you should see this:
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Figure 5: Attach GHS Data Window If you uncheck Refine Stations, you can input the number of stations you want. For HECSALV you want to input an odd number of stations. I’m going to change the number of stations to 255. Nota Bene Be sure to select Create Stations after you change the number of stations!! You will now notice that the number of stations has drastically changed. Now select the entire hull. Under the file menu, select Export Selected. Change the file type to a .gf file. Nota Bene gf means geometry file.
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Figure 6: Save Window Now its time to open HECSALV. This can be done by going to Start/ Courseware Applications/ NA470/ HECSALV/ Ship Project Editor. We will cover the other HECSALV applications in a different tutorial.
Figure 7: Start Window Cancel out of the opening menu. Go to File/ Import: 8
Figure 8: File Menu Be sure to change the file type to .gf in order to open your saved hull form.
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Figure 9: Import Window You will then see this:
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Figure 10: Geometry File Options You want to be sure your reference is from the FP. Enter your length between perpendiculars. Nota Bene Don’t change the units from feet. BE SURE TO ENTER THE LBP IN FEET! This is part of the program import/export system. Before we do anything, lets make sure the reference point and units are correct. Go to Tools/ Options.
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Figure 11: Options Window There is a tab for Units, so lets go there first and make sure the units are correct. Now lets go to References. Notice the Longitudinal is MS - Midship. Change that to FP. This can be done by selecting the MS and using the drop down box that appears. Now select OK. Double click on Particulars in the upper left.
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Figure 12: Design Particulars A menu will open that shows all your information in the units that your Rhino model was in.
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Figure 13: Design Particulars You will need to input the beam, draft and the design draft line. We are almost done. We will now save our file: File/Save As. After you choose where you want to save it a menu appears where you can make comments of changes in this version:
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Figure 14: Save Window
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Tables
This section discusses how to create tables in HECSALV. 2.1
Hydrostatic Table
To generate your ship hydrostatics go to Tables/Generate Hydrostatics:
Figure 15: Tables Menu Nota Bene Switching from the R/V Lemuria to a container ship hull. A dialog box should appear with the following options:
• General - Trim, change reference point, density and heel • Drafts - Change the number of drafts you want to analyze • Trim Corrections Nota Bene If you are unsure of the coordinate system in HECSALV, it should tell you when you type in a number. Notice in Figure 16, its 0.17A where “A” is aft. If it was forward a “F” would appear. Similarly in the Port/Starboard cases a “P” would appear for Port and a S for starboard.
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Figure 16: Hydrostatics Generation Options When the values seem reasonable then click on “Generate”. After a few minutes a new option will appear:
Figure 17: Explorer Menu Under Tables, select the Hydrostatic folder and an item called “Hull” will be there. Click on the “Hull” item in order to view your results. A series of tables will come up describing the hydrostatics of the ship at different drafts:
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Figure 18: Hydrostatic Results 2.2
Bonjean Curves
To generate the Bonjean Curves go to Tables/Generate Bonjeans:
Figure 19: Tables Menu A dialog box will appear:
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Figure 20: Bonjean Generation Window You can adjust the drafts at which your ship will be analyzed. Nota Bene Recall that Bonjean Curves are used for describing station area curves. When you are satisfied with the drafts, select generate. Again on the side a Bonjean Curve option will appear. Select it.
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Figure 21: Bonjean Results Since there are hundreds of stations describing your ship, there are hundreds of curves to describe the stations. By copying the data into excel you can select the stations to plot. 2.3
Cross Curves Curves
To generate the Cross Curves go to Tables/Generate Cross Curves:
Figure 22: Tables Menu
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A dialog box should appear with the following options: • General - Density, heel direction, trim GMt or KG, TCG and Pole Height • Displacement/ Angles - Change the number of displacements and heeling angles • Downflood Points - Points vulnerable to flooding
Figure 23: Cross Curves Generation Window Nota Bene You only need the GMt or the KG. Nota Bene Recall from class about the Pole Height. If Pole Height equals the KG then you can plot the curves as your GZ curves. If you set the Pole Height to zero then you must make a correction. When you are satisfied with the displacements and angles, select generate. Again on the side a Cross Curve option will appear. Select it.
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Figure 24: Cross Curves Results Now you can create your Righting Arm curve.
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Compartments
Now lets divide the ship into compartments. This will be usefull for the Damage Stability information. Go to Geometry/Generation Tables.
Figure 25: Explorer Options In the empty line type in a label for your compartments.
Figure 26: Table Generation To create the departments, simply double click on the box next to the label.
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Figure 27: Compartment Generation Now input all the different spaces of your ship. Remember you need to account for all the space so don’t don’t forget about the area forward of the collision bulkhead and aft of the Aft-peak bulkhead. When you are finished select the generate button in the lower left corner.
Figure 28: Compartment Generation After you have generated all your compartments, you will be able to see the compartments in the general view of your ship.
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Figure 29: Compartment Results
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Floodable Length
Do a search for “Floodable Length”.
Figure 30: Start Menu Import your “.shp” file to start the process.
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Figure 31: Floodable Length Window First go to Definitions/Basic.
Figure 32: Definitions Enter the permeabilities you wish to check. Check with the regulations and the Coursepack to verify the condition you need to meet. Next go to Project/Units. Here you can change your reference point. You will want to make sure your reference point is from the FP to match the rest of your project. Nota Bene Unlike in the Ship Project Editor, you will need to double click the reference you want.
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Figure 33: Units and Coordinate System Next go to Definitions/Bulkheads.
Figure 34: Bulkheads Input your bulkheads. After you input one bulkhead a new space will appear allowing another bulkhead to be inserted. When you are finished go to Calc/Run Calc. The process will take a couple minutes to finish. When the program finishes, go to Results/ Basic.
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Figure 35: Floodable Length If your bulkheads do fail you can change them without recalculating. The time spent calculating was towards forming the permeability lines.
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Damage Stability
Nota Bene Before you start this program, be sure to have created the compartments in your design. Start by searching for “Damage Stability”:
Figure 36: Start Menu Select the Damage Stability program and it will prompt you to select your “.shp” ship design file.
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Figure 37: Damage Stability Window First go to Project/Units/Prec.
Figure 38: Damage Stability Window
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Here we can change the units and coordinate system. Like in the Floodable Length Program, you need to double click the coordinate system you would like to use. Next go to Project/Stability Criterion.
Figure 39: Project Criteria Here you can change the criteria requirements. Nota Bene For NA470 you will want to use the Deterministic approach. If you are interested in the Probabilistic approach, I have some papers you can look at. After you have selected your criteria, select “OK”. Now we will go down the different options of the “Definitions” drop down menu. Drafts Here you can set the testing drafts. You will also need the GMt or the KG and the TCG.
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Figure 40: Drafts Compartment Status Here you can set whether a compartment is damaged or intact at the time of the test.
Figure 41: Compartment Status Damage Cases Here you can change which compartments get damaged in the tests. Simply double click on the compartment that you wish to test. You can test a series of compartments by selecting more compartments.
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Figure 42: Damage Cases View Damage Cases Here you can view the damage cases you selected in the option before. You can use the arrows to switch between cases.
Figure 43: View Damage Cases Subdivision This is used in the Probabilistic approach. Your compartments are further defined to be used in the probabilistic equations. Permeability Definition Here you can set the permeabilities of the different compartments.
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Figure 44: Permeability Definition Densities Here you add the density of the fluid inside any tanks in the model.
Figure 45: Densities Now when the drafts and damage cases are set the program will begin to start its calculations. If you need to restart the calculations, simply go to tools/Force Update or Force Complete Recalc. The calculations should take less than a minute. The Results can be viewed in either “Summary Results” or “Detailed Results”. A more convenient way to view your results is to through the print preview option. File/Print.
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Go to
Figure 46: Printing Options By selecting what you wish to see, you can “preview” the results. It is somewhat easier to navigate these results than the “Summary Results” or “Detailed Results”.
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Conclusion
Congratulations! You now have seen a basic overview of HECSALV. By continuing to play with the program, you will learn more of its quirks. Good Luck!
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