Adding Bulkheads 'n stuff to Freeship model

Discussion in 'Software' started by lewisboats, Feb 18, 2008.

  1. lewisboats
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    lewisboats Obsessed Member

    Adding furniture to a hull:

    To add bulkheads, bunks, cockpit seats, even consoles and such, extrude a handy boundry edge (the shear is good) by .1 units, then extrude it again by 2 units. Zoom in on the first extrusion and delete the two lines that join the larger panels. This gives you a new panel floating in mid air. Shape the panel to what you want (if a flat panel...to the length and width you want)(if a box by extruding the edges further to complete the shape).Assign the shape (or panels of a complex shape) to a new layer(s). Move the shape to the position you want it by highlighting all the lines, using Transform/Move then shape it to fit loosely. Use the shaded mode on the perspective view, along with varying the waterline to find gaps between the inside of the hull and the edges of your shape and adjust to fit. Move the perspective view around with the points enabled to see if any penetrate the hull exterior. Correct any that land outside the hull and this should get you quite close. When creating panels with the offsets for the parts, allow a bit of extra to trim to fit. In the layers properties add density and thickness to get a CG of all the panels to help with weight calcs. Luan is 38 lbs per cu ft which is 1 4x8 sheet of 3/8" ply...Ocumme is 28 lbs per sheet. 3/8" is .375 ft thickness... for any other type find the weight of a 3/8" sheet of 4x8 and this is the weight of 1 cu ft.. If you place a plane under or penetrating the waterline you must make it an enclosed figure for the hydrostatics to work. always extrude surfaces UP if possible so you have a sealed surface under the waterline and always extrude all the edges when extruding perpendicularly to a plane. It's a pain to move all the extra points and such but some can be removed without harming the shape. Moving an enclosed box takes a bit of patience but it is worth it when you can trim the hull properly and account for most if not all weights. The only problem is that whatever you put in is mirrored on the other side so asymetrical areas like the galley get mirrored. Best to put a box to represent galley on one side and a locker or something similar on the other.
    Read pictures from left to right top to bottom.


    Steve
    PS: missed a pic so it is out of sequence (pic of point outside of hull)...should go before the first perspective pic
     

    Attached Files:

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  2. deepsix
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    deepsix Senior Member

    I would like to add that it is worth while saving the flat panel as a part, this way you simply import it whenever you need it rather than extruding and deleting lines.

    When adding a bulkhead, I like to add a station at that point, then turn off all layers except the flat panel and simply add nodes and drag them to fit the station intersection in section view. You can use waterline intersections in a similar manner for horizontal panels.

    It is possible to turn the symmetrical option off in the layer properties window so that you do not need a locker and galley opposite each other. Just keep the center of gravity in mind.
     
  3. lewisboats
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    lewisboats Obsessed Member

    Maybe in Delftship but not in free ship...at least not in the copy that I have.

    Steve
     
  4. deepsix
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    deepsix Senior Member

    Is greyed out because "use for hydrostatics" is on, turn that off then you will be able to uncheck the symmetrical option. I tested on freeship 2.83+ and on v2.6, it works fine
     
  5. lewisboats
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    lewisboats Obsessed Member

    Ahhhhh!!!! did NOT know that....thanks much, works like a charm.

    Steve
     
  6. deepsix
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    deepsix Senior Member

    Im glad I could help
     
  7. drshaddock
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    drshaddock Design Engineer

    Thanks to both of you guys--saved me days of work!

    What about finding the intersections of layers? It seems to me that if you inserting a new bulkhead, for example, and made the bulkhead extend beyond the hull, and you used the Intersect Layer command to find the intersection of, say, Hull and Bulkhead3, a new set of points would be created where Bulkhead 3 hits the faces and edges of Hull. According to the manual, this new line of points can also be made into a control curve. It would seem logical to me that you could then delete the exterior parts of the bulkhead... Is this just too easy? Of course, it's easier for me to offer the idea than to go check it out--I'm supposed to be wrapping up the design of an engine wiring harness tonight and just took a break to browse. Thanks again for your ideas!
     
  8. deepsix
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    deepsix Senior Member

    I had not thought of this before so I gave it a try. It seems that the intersect command adds a node to an existing edge where another layer intersects that edge. In order to add a bulkhead using this command, the bulkhead part that is extended beyond the hull boundary must contain a series of closely spaced edges(I used vertical edges). A node will be added to the edge where the layer intersects it.

    The method does work but adding the edges and deleting the remaining nodes takes a long time. I prefer to add a station intersection, import a basic bulkhead part, and drag the nodes of a bulkhead part to the station intersection line.
     
  9. lewisboats
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    lewisboats Obsessed Member

    Think you could post a few pics on the process?

    Steve
     
  10. deepsix
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    deepsix Senior Member

    Method 1 - Intersect Layers

    1. Create a flat sheet with multiple edges. I have only added vertical edges but a complete grid would work better. Save this as a part.
    2. Open model, import part and move it to an appropriate location (Figure 1)
    3. Point>Intersect Layers, will add nodes to the edges on the bulkhead panel(Figure 2)
    4. Delete the nodes which are not required.

    [​IMG]
    Figure 1

    [​IMG]
    Figure 2

    I dont like this method, it is slow and tedious, but may be more accurate.

    Method 2 - Station Intersection

    1. Open your model and import or create a flat bulkhead panel
    2. Calculation>Intersections. Remove all existing station intersections and add a new one at the location of the new bulkhead.
    3. Make sure stations are visible - Visibility>Station if station is not visable
    4. Turn off all layers except the new bulkhead
    5. Move bulkhead part to the correct location in plan and profile views
    6. In body plan view, add nodes and drag them until they match station line

    [​IMG]
    Figure 3 -Blue is station intersection line, red is the flat bulkhead panel.

    [​IMG]
    Figure 4 - Simply move the bulkhead panel to match the station intersection line.

    [​IMG]
    Figure 5

    [​IMG]
    Figure 6

    This is how I would do it, but I am sure that there are better ways. If anything is not clear, ill gladly explain in more detail.
     
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  11. lewisboats
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    lewisboats Obsessed Member

    excellent info and I'll have to play with it to get comfortable. Here is a poser for you...how would you go about putting bilge keels on a hull? Looking at 2 keels about 20" deep, around 5.5 ft long (at the root) with a 55 or so deg rake forward and a 30 or so degree reverse rake aft, plate steel so there is no NACA shape to speak of. I tried backing the boundry edge off the centerline and extruding and shaping but it came out crappy with leaks. Perhaps a .part but how do you eliminate leaks?

    Steve
     
  12. Guest625101138

    Guest625101138 Previous Member

    Add a cyclinder, shape it to suit. Seal off the lower end by extending the edge and closing to a point. Move it to position and ensure the top extends through the hull. If it is left as symmetrical layer you will have two of them.

    If the keel is basically a flat plate it will stall at relativelt low angle of leeway.

    Rick W.

    PS Delftship Pro has a rudder and keel wizard - not sure if Delftship free has this.
     
  13. lewisboats
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    lewisboats Obsessed Member

    it is a rather common feature in GB. Most are described as steel plates...although the possibility exists of building some shape into it with epoxy and filler. right now I am more interested in getting the keels into the drawing to work on the hydrostatics and get the sail balance going. Thanks for the info.

    Steve
     
  14. lewisboats
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    lewisboats Obsessed Member

    OK...got the bilge keel done but I've run into a problem...it isn't being recognized properly in the hydrostatics. Select it to be included and the LCR only moves a tiny fraction...regardless of the placement of the keel(s) along the length of the hull. I have even taken the keel down to 6" long and it still doesn't change anything. Got any ideas? I attached the .fbm of just the hull, the keel and the skeg.

    Steve
     

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  15. deepsix
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    deepsix Senior Member

    I will have a closer look later, have you turned on the use for hyrostatics option in the layer properties box?
     
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