Lloyds and Germanischer Lloyd

Discussion in 'Class Societies' started by Arvy, Nov 6, 2007.

  1. Arvy
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    Arvy Senior Member

    Hi all,

    Just wondering, are these the same organisations but with different locations, or are they not related at all. And in the case they are not related, which of the class rules can be used best for yachts build in holland?

    As the GL rules are available for free, the LR rules are to be bought but they don't state any pricing information and just give you an opportunity to let them bill your credit card or sent an invoice... but I guess I must have missed the pricing somewhere. The GL rules are more attractive this way and faster to get an hold on, but will they suffice.

    Grtz,
    Arvy
     
  2. Guillermo
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    Guillermo Ingeniero Naval

    Hi, Arvy!
    GL and LR are totally different organizations (and competitors), as far as I know.

    Cheers.
     
  3. Arvy
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    Arvy Senior Member

    Hi Guillermo,

    Thanks for you reply.

    Now I am still confused which class rules I could use best for a home designed to be built ship. The GL are available for free, Lloyds are quite expensive and the ISO norms aren't final yet (and it is very unclear to me which ones have to be used as they all seem to link to eachother).

    I think this is rather confusing.

    Grtz,
    Arvy
     
  4. Olav
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    Olav naval architect

    Arvy,

    use the GL rules and regulations. Admittedly I've never worked with LR rules, but since the IACS members agree to accept the scantlings of each other, you shouldn't come out with too different results.

    The GL rules are quite straightforward and thus very comfortable to use (ABS rules, for example, are written "upside down", so you have to work from the end of the chapter to the beginning).

    ISO (I assume you refer to ISO 12215) gives only very vague information on how to actually build structures. It's merely something to determine the design loads on the ship, if I remember correctly.
     
  5. Landlubber
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    Landlubber Senior Member

    Arvy,

    Could you please direct me to where GL Rules are available free of charge. I have visited their site and cannot find such an offer anywhere, except the Pilot Scheme for up dates. The pdf attachment lists the contents of the rules, but does not include them, I guess I am looking in the wrong place.

    Kind regards, Landlubber
     
  6. Olav
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    Olav naval architect

    Landlubber,

    have a look here. ;)
     
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  7. Arvy
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    Arvy Senior Member

    Thanks Olav :D

    I was indeed talking about the ISO 12215 rules. I have started working through the GL rules for yachts < 24 meters and I am designing a 40 foot sailing yacht to be build out of steel. In the section about FRP the effective plating is mentioned, but in the metal hull section it isn't. Do you have any idea if the effective plating for frp is also to be used for metal hulls?

    In FRP they say the effectve plating width is from centre to centre of the unsupported plate with a maximum of 300 mm. Can this also be used for steel or aluminum?

    Landlubber: in the pdf that olav pointed you too, just click on the index on the left to open other pdf's they are like hyperlinks to the rest of the documents.
     
  8. Olav
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    Olav naval architect

    Arvy,

    as I couldn't remember I just quickly browsed the metal hull chapter again (it's been some time since I used them to do the scantlings of a 15m aluminium patrol boat) and didn't find anything like the effective plate width that is incorporated in the calculation of the section modulus as in the FRP chapter.

    Ergo: The section moduli of the frames/bulkheads/stiffeners are treated independently of the plate to which they are fitted.
     
  9. Arvy
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    Arvy Senior Member

    Olav,

    Thanks for you reply (again). I already thought that the section modulus of for example the stringers were rather small (about 1, which could give a flatbar of 40x5 mm which seems perfectly acceptable with a frame spacing of 400 mm and a stringer spacing of 250 mm) to include the effective plating. I just wasn't sure because I might just as well do something wrong in my calculations.

    Well, luckily there are people like you that can help out, and I guess I must rely more on my experience to interpret the results of the calculations (too bad the experience goes back over 12 years).
     
  10. PI Design
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    PI Design Senior Member

    The LR rules we use for steel ships (>>24m) allow an effective breadth for plating of 40t, where t is the plate thickness. I don't know if this would be allowable for you though.
     
  11. Arvy
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    Arvy Senior Member

    Hi PI Design,

    Thanks for posting the effective plate width from the LR rules, I don't think I can use it, as I am using the GL Rules. In another thread (see link below) I already posted my thoughts about using effective plate width, and I think you cannot interchange the effective platewidth from 1 set of rules with another set of rules.

    see: http://www.boatdesign.net/forums/showthread.php?t=20111
     
  12. Landlubber
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    Landlubber Senior Member

    Thanks Olav, My version was only showing the index, after I had saved the doc, I can see now that I have to open every section to save the full field. Thanks again.
     
  13. Dutch Peter
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    Dutch Peter Senior Member

    Arvy, a stringer is generally a main strength member, this means of substantial proportions. What you mean by stringers looks to me as being longitudinal framing. You should make up your mind on the building methode as it sounds to me you mix the two framing methodes.
    If you stick with the longitudinals, you can expect your webframes about 1500 mm apart.
     

  14. Arvy
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    Arvy Senior Member

    Thanks Dutch Peter,

    From what I remember in the past (some 12 years ago, in the Netherlands) we used to call the thin flatbars running from fore to aft rather closely spaced stringers. These stringers are more like longitudinal framing indeed.

    I now switched completely to longitudinal framing, but decided to keep the framespacing at 800 mm.

    Grtz,
    Arvy
     
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