Which Design Rules do you use?

[BarendGrobler]

So there are the ISO rules; there are the various classes (GL, DNV, LR, ABS, etc, etc); and then there are a couple of “un-official” scantling rules such as the well known Dave Gerr scantlings.

So what do most guys / design offices use?
Do you use more than one?
I have for instance used DNV rules for High speed small craft when designing high speed military boats; but I used GL and LR rules when working on motor yachts. Now I’m more using ISO standards for sailing boats.
Sure, once you’re working on commercial cargo or passenger craft it will be one of the class societies, but which ones have you used?

[APP]

Originally Posted by BarendGrobler

So there are the ISO rules; there are the various classes (GL, DNV, LR, ABS, etc, etc); and then there are a couple of “un-official” scantling rules such as the well known Dave Gerr scantlings.

So what do most guys / design offices use?
Do you use more than one?
I have for instance used DNV rules for High speed small craft when designing high speed military boats; but I used GL and LR rules when working on motor yachts. Now I’m more using ISO standards for sailing boats.
Sure, once you’re working on commercial cargo or passenger craft it will be one of the class societies, but which ones have you used?

Hi,
Where do you download ISO for yachts?
For Catamaran yachts, I heard the most convenient ones are the French BV.
Regards
APP

[BarendGrobler]

Firstly; ISO is an independent International Organisation for Standards.
BV which you are referring to, is a class society, one of many (10 main ones).
Most of the class societies rules are available on their websites; have a look at the "Class societies" forum-section on this forum.
The ISO standards you will have to buy. The ISO scantlings for catamarans are ISO 12215-7. However, part 7 is basically the same as part 5 (ISO 12215-5); so this is probably the one you want.

[Ad Hoc]

Originally Posted by BarendGrobler

.
.... but which ones have you used?

Whichever you are familiar with, comfortable with and/or the boat/shipyard prefer to work with. It is more than just rules and numbers. The personnel involved, the plan approval staff the surveyors, the Class fess, experience of the staff/surveyors etc all these are part in the selection process.

[BarendGrobler]

hey Ad Hoc
i guess you're right, it's not as simple a question as i'm making it out to be.

Thing is, i'm actually a class surveyor myself; but when i'm designing small craft (below 24m) i don't use the the rules of the society i work for, i prefer other rules; that is if / when i get to decide on the rules.

Thats why i'm interested in finding out what most designers use for small craft; kind of a survey of what most designers prefer.

[daiquiri]

Originally Posted by BarendGrobler

Thing is, i'm actually a class surveyor myself; but when i'm designing small craft (below 24m) i don't use the the rules of the society i work for, i prefer other rules; that is if / when i get to decide on the rules.

That's curious. Why is that so?

Reminds me of this eye surgeon who has examined me recently, I wanted to hear about the possibility of laser correction of my myopia. Well, he did tell me a lots of excellent and flashy things about it, expressed his favorable views etc... But the particular that remained mostly impressed in my my mind was - he was wearing glasses.

Cheers

[MikeJohns]

Depends where the boat is being built and which society covers that area. Also what's the relationship like between the yard and the local surveyor

Some materials are covered better with some, some types of vessel are covered better in others. Local support varies by region but these days email to head office is a good tool and all specific design goes to head office so local bureaucrats can be sidestepped. Usually though, the client dictates the class.

ABS OSRY has migrated to ISO but there's a gulf of difference between using ISO and a class approval process through to the finished vessel.

For budding yacht designers it may be best to look for whoever does the quickest cheapest plan approval and then use it, it will give invaluable feedback and an essential review. That comes back to who's present in your area and what are they like.

Even designing to scantling rules you can still get things muddled, the following thread was interesting: It illustrates a typical pitfall using class rules, it's not the role of the class society to ask why you have gone for such overkill and weight for example: Massive Stem bars ..........Why