watertight bulkhead

Discussion in 'Boat Design' started by Pammie, May 28, 2018.

  1. Alik
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    Alik Senior Member

    The rules say they we need to make holes in topsides, to let the boat sink at turn, right? ;)

    They are applying requirements deriving from load lines code, to the craft below 24m. Those are not intended to apply, see preamble of the code.

    Any reasonable surveyor would not require anything so dangerous. He should have brain!
    Thus, in this case, classification society is using the rules to reduce safety... Clear enough.
     
  2. Ad Hoc
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    Ad Hoc Naval Architect

    Well, please quote the rules to avoid ambiguity.

    No.
    Because you haven't quoted the part of the rules you are referring to.
     
  3. Alik
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    Alik Senior Member

    I don't have to quote any rules. This was official letter from senior RS surveyor doing the design approval. This well proves that class can cause degradation of safety, due to lack of understanding of small craft specifics by classification society surveyors. I just share our experience, You like it or not.

    I am not trying to convince You, we all know You are designing ships and have very limited experience with small craft. But there are other readers here who might know that classification does not necessary mean safety, and can mean degradation of safety.

    In every particular case boat builder needs to choose 'the right tool for the job' - ISO Small craft standards, specialized small craft standards like DNVGL St.0342 or MCA MGN280, or full classification - depending on the purposes of the project. Anything different from class does not mean less safety, and often means more safety because specialized standards better reflect specifics of small boats.
     
  4. Ad Hoc
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    Ad Hoc Naval Architect

    If you are unable to quote the rules, it proves nothing.

    I have more difficult surveyor stories/examples than I can shake a stick at. Your role, is to navigate around their ignorance of their own rules. :rolleyes:

    If you say so.

    You seem not to understand the distinction between Class and statutory. Since if you decided to use ISO for the structure of boat you posted earlier, it must still comply with statutory rules.
     
  5. Alik
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    Alik Senior Member

    I fully understand the distinction. Any boat should first of all comply to common sense. Making holes to interior just 200mm above WL is not common sense, whatever any rules say. This is ignorance of surveyor, and Your typical casuistry which we see a lot on this forum.
     
  6. Ad Hoc
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    Ad Hoc Naval Architect

    You have yet to quote/cite the rules that which you are stating.
    Thus in the absence of any rules for discussion, it is your subjective opinion of such, as nothing else to go on for a basis of discussion of its merits or otherwise.
     
  7. Alik
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    Alik Senior Member

    You want I quote the RS surveyor's letter, it is in Russian?? Again, I am not supposed to quote any rules. They are applying rules deriving from load lines code to this 10m boat, go and read it if You want.
    The difference is I share our valuable real-life boat design experience, and You can only offer lengthy quotes from rules for ships. Such discussion is waste of time.
     
  8. Ad Hoc
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    Ad Hoc Naval Architect

    Says who?

    So, quote the article of the rule they are citing from - the LL rules are in English too :D


    If you do not wish to understand the rules, this will be your default position every time - since, being argumentative with the surveyor and others that do not see your point of view, does not progress the design you intend it to be.

    We've done many like yours, see below, with similar arrangements :

    upload_2018-7-25_10-5-40.png

    upload_2018-7-25_10-6-32.png

    upload_2018-7-25_10-7-24.png

    Understanding the rules is always the key. But you are electing not to. That's your prerogative.
     
  9. Alik
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    Alik Senior Member

    You have nothing to offer other than quotes from the rules. No value. Get some small craft designer experience first, before lecturing the experts doing it every day.
    As to the rules, I am in few committees making/reviewing the rules and standards.
     
    Last edited: Jul 24, 2018
  10. TANSL
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    TANSL Senior Member

    Rules, rules, rules, .... rules are the refuge of those incapable of thinking, of innovating. "Quote the rules", what boredom !!!, is it no longer worth the common sense or the designer's experience? Is it no longer possible to argue with the inspectors interpretations of the norm or alternative solutions to it? Is it true that a designer can only be justified by strict compliance with the norm, there are no technical arguments? Poor to us !!
     
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  11. rxcomposite
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    rxcomposite Senior Member

    In my profession, I have come into contact with several Classification Societies. Deeper that mere contact with just the surveyors. These CS is an organization and as such have a hierarchy. There are many level of disciplines involved and the people that formulate the rules are not just Naval Architects. They maybe one or more Electrical Engineers, Structural Engineers, Civil Engineers, Marine Engineers, Merchant mariners, Mathematicians, ect as the organization deems necessary.

    The rules formulated is not a one man rule. It is a cohesive collected thought. The surveyor is not the end itself because he is the representative of the company. If there are any conflict/lack of/excesses with the rule, the surveyor discusses it with his boss. If it has merits, the experts are convened.

    I don't think a mere surveyor would be so thick skulled that he will refuse or take up any discussion or take up with his boss the rule in question. After all, it is an organization and he has the backing.
     
    Last edited: Jul 25, 2018
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  12. Pammie
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    Pammie Senior Member

    Ofcourse I'm no expert but I have been reading about Class Rules the past weeks. I noticed there is a lot discussion about it on the internet; some preferring one standard, others another. But isn't it so that every mathematical model is besides the reality per defenition? Physicists have been looking for an unified field theory for more than 100 years... Still not complete and will never be. The art is to know when it almost and mostly does and when to use one's healthy farmers sense (a dutch saying). In my almost 40 years of engineering experience (electronics, software and herbal formulae) I have come to believe there is a special law of preservation of energy which is called "law of preservation of misery". Having experience is very helpfull to know which way to go or not to go and I hope you will help me with that.

    The discussion has been led off-topic the last pages (no problem with me though) so I think I will start a new topic to discuss all kind of different design issues regarding my project.
     
  13. Ad Hoc
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    Ad Hoc Naval Architect

    It is not about the definitions Pammie. It is about the purpose of the application of said.

    As previously noted.
    Classification is about safety of the boat and the systems onboard the boat.
    Statutory is about safety of the crew/passengers and the associated system on board the boat for their safety.

    Basically Statutory is trying everything in its power to prevent you from going to sea...why?...because if you do not go to sea, there is no risk, it is that simple. So, if you do elect to go to sea, they place rules that must be satisfied in order to minimise the risk of going tos ea that could lead to loss of life.

    If you decide to design a plastic bath tub and go to sea in it, you can do...your choice your life. Nowadays the big EU has step in with its rules for pleasure vessels.
    If you decide to make that plastic tub carry passengers or crew that is used for commercial gain, then it is a totally different ball game. Safety is paramount.

    This has still nothing to do with maths.

    Thus below 12 passengers, the rules are fairly relaxed and easy. But once you go over 12 passengers, it changes into 'big ship rules'. Why 12 passengers, historical, and an anachronism. But it is the rule. Like it or lump it.

    We designed 6 small vessels, 5 of which were carry less than 12 pax and the 6th had 16 pax. The 2 boats were identical in every way, except one carried 16 pax. The rules we had to comply with because it carried 4 more pax had a major impact on the design, notably the weight and cost of the vessel. But, prior to contract we knew this, thus we made allowances for these rules. One must know the rules in advance, and often it is not ours to ask why...but merely to comply. Everyone else must do, why must we think we are any different? There are provisions of an equivalence of philosophy, one must simply argue the case and demonstrate equivalence to the statutory body. That's it.

    Thus it is all about administration of compliance and a paper trail of evidence should something go wrong...and it starts with carry passengers/crew for commercial purposes versus personal pleasure craft. One has significantly greater sets of compliance than the other. But - so what?

    So back to your point, whilst it may appear off topic, it is all design related. Since depending on what YOU wish to do with YOUR boat, can't escape the fact that YOU must comply with a set of rules somewhere along the way. Which, depends upon what you wish to do with your boat...forewarned is forearmed.
     
  14. Alik
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    Alik Senior Member

    On recreational boats under 24m covered by ISO Small Craft standards, there are no passengers, all persons on board are considered as 'crew'. This also applies to recreational boats used for commercial charter. There is always a proper niche to go with small craft, according to their limited budgets and specifics. Say, we got recreational boats licensed to carry 20+ persons which are not passenger boats.

    And yes, agree with TANSL, not all passenger boats are required to have a 'class'. In many jurisdictions, domestic service passenger boats would not have any formal class. Say, we recently did catamaran to Australian NSCV standards and despite it is a passenger vessel there is no requirement to have any formal class.

    As to 'statuary requirements', these are requirements of international maritime conventions, such as SOLAS, MARPOL, etc. Don't get fooled, by definition most of them apply only to ships involved in international voyages, and will have other limitations on application, say size and type of ships. They have very limited application to small craft.
     
    Last edited: Jul 25, 2018

  15. Ad Hoc
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    Ad Hoc Naval Architect

    This sounds exactly like:

    and
    So, you quoting rules defining "crew" now has value... i'm confused? :p

    As I said before, once you know the rules, you use them to your advantage...in this case, by not calling it a 'commercial vessel', one navigates around said rule.
    Sounds like using the rules again to me! But i though doing such was a case of :

    Again getting very confused now....is one using the rules to ones advatange or not?

    That's correct. No one ever said it was a requirement. If you satisfy the flag state rules, whatever they may say, it is not mandatory to be certified by Class.
    We've done that in the past even have 30m high speed passenger cats running without class...again, so what, nothing new there.
     
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