watertight bulkhead

Sorry, incorrect Alik.

Im talking about the administration of ISO, nothing else.

You're introducing a non sequitur:

I have not said they are or are not the same. As that is not the point I am stating above.

Joe Bloggs down the road, wants to build a small 5m RIB. He builds one that his mates like, so they ask him, can we have one, he sees the chance to make some money....so what rules of compliance can Joe Bloggs use for his 5m RIB, because anything he sells, must now have a measure of compliance, a CE mark as a minimum. Thus where does he turn?

Well, he doesn't or can't use Class rules....for endless reasons.

And, as stated above:

So, Joes Bloggs now has the option of using ISO rules.

But where does he buy his aluminium from?....er...no such thing as an approved ISO grade plate..or ISO approved filler wire and so on. Can you buy it from down the road at his local chandlery?

Yes!....why?..because ISO states:


SO Joe Bloggs can buy just about anything, as there is no formal measure of compliance for the sourced materials.

What about if there are failures, who does Joe seek? Well can't seek ISO, as the set of 12215-5 rules does not address these:


So, rather than repeat my statement above, let's use ISO's reason for their rules:


Thus, Joe Bloggs can use ISO rules to get his all important CE mark. But it comes nowhere near the measure of compliance required for Class build.

But..and this is the whole point that is lost on everyone, no one said it is. It is just a method to obtain by a quantitative perspective set of scantlings, nothing more, nothing less...and ostensibly for those that (I shall repeat again):

Simple!

 

It can also be affirmed, with all reason and foundation, that "in general, Class is for those not designing / building to ISO". And let me, again, cite a paragraph that appears on ISO 12215-5 page 9: "For the complete scantling of the boat, this part of ISO 12215 should be used. in conjunction with part 6 for details, with part 7 for the multihulls, with part 8 for rudders and with part 9 for appendices and rigging points ".
The ISO standard is what it is, it serves for what its editors created it and it is as technical as any other regulation. A very different issue is that some administrations do not demand great things from amateur builders (say Joe Bloggs).

 

2AdHoc:
OK if so yes I agree, the administration is very different. Classification Societies are actually making profit on certification of everything, some of them will certify every screw that goes into the boat. The same refers to the materials. The more calcs and tests they require, the money they get - very simple. It is not directly related to safety but more on increase of income. Tell me what responsibility classification society takes

In ISO, they declare minimum properties to which the material should comply. It is the responsibility of designer/builder to use materials according to specifications of the manufactures.

On other side, ISO standards are much better in terms of usability, as they are written by practicing specialists, in collaborated way. Rules of Classification Societies are often written by narrow groups of theoreticians, with a lot of errors, omissions and impractical design approaches.

So, my opinion, to tell it straight: class rules are developed to screw shipbuilders; ISO are developed to help boatbuilders

 

Indeed, and that is exactly the point. Just like when you buy a car say like a Ferrari, if something goes wrong, you want a genuine part fitted, rather than a cheap knock off alternative.
But who says the cheap one won't work...and that's the point....it's cheap, take your pick, and accept the consequences. But if the cheap one fails and causes even more damage, that's when it gets expensive, as Ferrari will walk away and say you fitted a non genuine part.

That!

They ensure that type approved means just that. So, take an M25 Class 70 S/Steel bolt that is made in a mill which has been checked audited an approved that the metals are what they say they are, the processes to make them and the testing to ensure quality and minimum properties are satisfied. But you could buy a shiny looking M25 bolt down your local shop where the owner says he buys in bulk from China and has no idea what grade they are. So, when you buy that more expensive bolt...it comes with the seal of approval that it does what it says, or buy the cheaper one..and you have no idea if when you torque it up...it'll fail or not. Everything in life costs.

So does Class.

But they also make sure you buy from type approved sources to guarantee those mechanical properties.
ISO does not, as noted above in the quote from ISO, and your comment too:

So, Joe Bloggs can cut corners to make his 5m RIB, because he bought knock off ally from some bloke down the road. It is shiny it is ally, what more do you need to know? No one checks it for compliance...as that is not ISO's role!
Just use the rules, oh yeah, the rules you have to pay for too.....whereas most Class rules are now free.

Where only 70% agreement between all those bodies is required...and can be altered by local authorities too. Hardly common agreement.

Nope, they are written from feedback from inservice vessels and R&D spent to refine and improve the rules, where needed. And, like LR, have a group of non-LR staff to independently review the rules to ensure it makes sense and has industry feedback prior to being issued.

ISO as I said from the ouset, is for small boat builders not wishing to use Class, which requires far more compliance to ensure traceability and adherence to standards from the drawing board to the final product and everything in between. Just like a car.

If you haven't seen the 12215-2018 rules yet, it is getting even worse and trying to muscle into the Workboat side...and it is a mess.

 

I did, as member of the group. As well as DNVGL group as well
Agree that ISO is becoming too complicated. But can't compare with classification societies rules, where developers often have no clue of practical engineering tasks; they just miss parts of formulas/values and publish that

 

More on this matter, if one saw DNVGL 2016 HSC rules for composite structures, design pressure for each sandwich panel should be calculated in 4 corner points, the formula also includes flare angle and waterline angle, measured at each point I can imagine the designer is doing all these measurements and calcs... By the way, withe boat's running trim, wouldn't the waterline angles change? This is a masochistic approach to design, nothing to do with engineering practice, and no understanding of approximate nature of such design loads. No understanding of design business as well. Yes, this 'design to class' will cost, but does it give any additional safety? The answer is NO, just wasted manhours and useless exercise with numbers.

 

Can a builder self-certify the boats they build as meeting the ISO rules for purposes of apply a CE mark, or must they use a notified body?

What is or should be the role of a notified body in certifying that the builder has used materials which result in a vessel which meets the ISO rule requirements? What information or documentation about the materials should the builder have available?​

 

Alik, are you talking about the new rule of DNV about the 4 edges rule? This a close fit or patterned after Timoshenko method. ISO has something similar (1-2 system) as outlined in 12215- 5 table H.3 to find the Effective Aspect Ratio (EAR). ISO referred also to Timoshenko in its annex section. It may appear to be complex but it is also in ISO rule. Average users use the coefficient 83.33 in rule bending moment as outlined in equation 52 and table H2 but should be amended as the rule specifies calculations in the short side and long side of the panel using EAR.

 

None. There is no minimum mechanical properties required. The builder can choose freely the materials s/he wants but there are 3 level of test (or non test) required.
1. Level A-Methodical testing of the finished material according to specified international/national standard specified in the rule if manufacturing.
2. Level B- Occasional testing in using recognized standards as proof that the finished material (laminate) default values are met or exceeded while building.
3. Level C- No test but the values used should be computed as 80% of the max value of the default standard (predicted finished material values by computations outlined)

1 and 2 in the presence of an ISO rep.

 

Totally disagree.
Those formulating the rules in Classification Societies are very competent and professional, with huge resources for R&D. It seems you're conflating, disagreement with dissention.
It is also a very broad brush statement and somewhat disingenuous to those the do this job very professionally to the best of their ability.

ISO - is ostensibly a group of people that meet to agree a common standard. That's all.
Independent objective research can only come from independent sources. Working professionals (whilst knowledgeable) are not objective - your comments above are evidence of that.

The 4 corners you cite have always been in DNV rules, in the 2016 rules it is just expressed differently. And is also the basis of any structural design, that of "fixity", the end conditions!
It simply wasn't addressed in 2008 ISO...not sure why?!

That's for you as the designer to establish. If you don't know the behaviour of your design and what it can or can't do...who does?

As noted from ISO, also above but with the emphasis highlighted:


The structural design rest solely with the designer, not the rules per se.

Says who..what evidence do you have for this statement?

Again, you're conflating a personal opinion about the implementation of said rules.
Where is manhours of calculations given as an input into the scantling rules and a fudge factor if you can cut corners and do it quickly, or you've taken too long so given dispensation?

One can elect to become "self certified", or just get a 3rd party to review and stamp the dwgs as "approved" or "compliant" as such.
As noted at a RINA WG Meeting sometime ago:


which is in stark contrast to Classification Societies procedures:


So, as the designer you take your pick. And that's it....just follow the rules. None are perfect, but Classification Societies requires far more demonstration of compliance and independent compliance too.
Choose your poison!
​

 

No, I am talking about design pressures in DNVGL.

 

2AdHoc
Regarding Your references that ISO12215 does not require validation of mechanical properties, and classification society do. This is not true.

ISO has 3 methods of establishing structural properties of materials: method a) is testing, method b) is testing of glass content only, method c) is no testing, but 20% margin to structural properties established by empirical formulas in ISO12215-5 Annex. So the designer can choose any, if it fits in project's budget. Regarding classification societies, not all of them require testing. Say, we just did composite project to LR without any testing, using formulas for structural properties from their Rule book (besides all, those formulas are almost same as ISO). Another example: GL HSC2012 rules is using CLT method for structural properties of composites, without mandatory testing.

This is all described in my paper published by SNAME/CPBS2014. Those on RINA meeting probably should read it

 

IMO you have misunderstood the sentence. It means the longitudinals to be high enough where they meet the watertight bulkhead ie at least 2'to 3' higher (towards the centerline of the boat) than the tabbing against the hull on the bulkhead.

 

I see you haven’t answered my question above about giving additional safety re: ISO v Class?

But you’re missing the elephant in the room.
ISO 12215-1, 4.1.3 and 4.2.7, states it is just a written declaration that it has been done. That’s all. Therefore, the onus of “approval” in that sense still rests/lies with the builder being open honest and understands what they are doing, not an independent surveyor, and recording what they have done.

Who verifies/approves your scantling calculations for ISO compliance?
And where is the manhours input to get better scantlings, as you seem to imply?

All Classification Societies allows this.

But you must use their minimum allowed values. Reason being:-
1) You must use materials that come from an approved source, i.e. the resins of matt etc, has been formally tested witnessed at made according to Class approved QA procedures and the final product satisfies minimum mechanical properties, thus a long chain of events to verify the product being used is well known to Class as doing “what it says on the tin”.
2) The minimum allowed values can then be used with confidence. Some may bleat it produces thicker or heavier scantlings that otherwise would. Well, that’s the point. Either you get proper certification and verification of what you wish to use, or, you accept the bare minimums values and it is what it is. As noted in Pt.8. Ch.3 Sec.1 Tables 3.1.4-3.1.7.

I do not know of any ISO approved materials. Class approved – yes. ISO – no.

I am offered many papers to read for accuracy and critical review prior to publication


ISO is becoming a behemoth and it won’t be long before many will see Class as an easier alternative. Thus shooting themselves in the foot!

 

It is not a pressure.
It is, as noted, just a more representative way of showing/establishing end fixity of a panel/structure. That's all. It has always been there, just presented in a different way in the new rules.

For ref, Pt.3 Ch.4 Sec.6: