HULL MATERIALS....3D Printing. Croatian Motion.

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Robert Grubisa
Posts: 143
Joined: 29 Nov 2003, 22:15
Sail number: CRO 68
Club: JK Opatija
Design: Kantun 2
Location: Rijeka, Croatia

Re: HULL MATERIALS....3D Printing. Croatian Motion.

Post by Robert Grubisa » 24 Jan 2021, 13:30

Hi Graham,

I am interested to know what is the outcome of the discussion here. A lot of a time and effort have been spent here, much information have been shared. CRO proposal is defeated on the last IOM ICA General Assembly, so what will be the next step?

Just for note, any IOM 3D printed hull which is printed using the thermoplastic material with glass fibres is illegal. Well, if this is the will of the majority, let it be...

Lester invited people to answer on his questions. Some replies have been received and the majority is against the honeycombed construction. Honeycombed construction is prohibited in the Croatian motion proposed.

Personally, after all this discussion I don't see the problem with the original CRO proposal wording.

All the best

Robert
Robert Grubisa

Art Prufer
Posts: 3
Joined: 08 Dec 2020, 20:20
Sail number: CAN 42
Club: WCRS -West Coast Radio Sailing
Design: DC7
Location: Vancouver Island, BC
Contact:

Re: HULL MATERIALS....3D Printing. Croatian Motion.

Post by Art Prufer » 01 Feb 2021, 00:49

The original 3D printing proposal also changed the rules for non-3D printed boats. That is why it failed.
If you propose changing more than one thing at a time, I suggest submitting a separate proposal for each change.
That way both changes are not defeated when only one fails.
Art Prufer
CRYA #1189 Can 42
https://westcoastradiosailing.ca

Robert Grubisa
Posts: 143
Joined: 29 Nov 2003, 22:15
Sail number: CRO 68
Club: JK Opatija
Design: Kantun 2
Location: Rijeka, Croatia

Re: HULL MATERIALS....3D Printing. Croatian Motion.

Post by Robert Grubisa » 01 Feb 2021, 07:59

Hi Art,

Could you please explain what has been changed for the non-3D printed boats in the CRO proposal except the proposed wording is changed in order to clearly allow all sorts of gel coats, resins with pigments and other additives as well as additives to thermoplastics which was not clear in the current wording of the class rules?

Please, let us know if there is any loophole in the proposal which can be exploited to make better non-3D printed hull than it is currently allowed?

Regarding the possible two submissions instead of the proposed one, it is much easier to make a harmonized technical sound wording which covers the whole hull material rules chapter.

All the best

Robert Grubiša
CRO 68
Robert Grubisa

Hiljoball
Posts: 278
Joined: 06 Jan 2006, 00:47
Sail number: CAN 307
Club: West Coast Radio Sailing
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Re: HULL MATERIALS....3D Printing. Croatian Motion.

Post by Hiljoball » 01 Feb 2021, 18:50

Hi Robert,
It is disappointing that you would go back to square one and start the discussion all over when we seemed to have reached a consensus on this thread that many would support a change that left the current materials alone and just made the minimum of line item changes that would improve 3D printing.

You ask what is wrong with your proposal – my view is that it changes the philosophical structure of the Materials section in a very significant way – with possible ‘unexpected’ consequences.

The current IOM class rule is a Closed Rule – and the Materials section follows that philosophy by listing only what is permitted. Your proposal changes the Materials Section completely to an ‘Open’ style, by saying all materials are permitted except those that are not permitted.

Here is an example – under your new wording, how would Texalium be treated?

John
John Ball
CRYA #895
IOM CAN 307 V8
In my private capacity

Robert Grubisa
Posts: 143
Joined: 29 Nov 2003, 22:15
Sail number: CRO 68
Club: JK Opatija
Design: Kantun 2
Location: Rijeka, Croatia

Re: HULL MATERIALS....3D Printing. Croatian Motion.

Post by Robert Grubisa » 02 Feb 2021, 15:32

Hi Hiljoball,

I am not starting the discussion all over and I don't see reached consensus to leave the current wording for non 3d printing hulld as it is now.
You mentioned that the proposal "changes the philosophical structure of the Materials section in a very significant way – with possible ‘unexpected’ consequences." Sorry, this sounds to me like some political phrase ;-)

It is difficult, if not impossible, to list only what is permitted in the Material section and therefore the proposed wording has been made restricting the fibre reinforcement material as a crucial one.

Texalium will be permitted as fiberglass-based fabric that has a proprietary finish and a thin coating of aluminum. Modulus of elasticity of the aluminium content is just below the best glass products.

---------------------

I contacted Graham, who started this thread, to hear his ideas how to materialize all the discussion here in the useful way (new proposal, new voting, etc.) I am sure that he will explain his thoughts when he will be ready to do so. I simply don't want to quote here our communication without his consent.

Best regards

Robert Grubiša
CRO 68
Robert Grubisa

Art Prufer
Posts: 3
Joined: 08 Dec 2020, 20:20
Sail number: CAN 42
Club: WCRS -West Coast Radio Sailing
Design: DC7
Location: Vancouver Island, BC
Contact:

Re: HULL MATERIALS....3D Printing. Croatian Motion.

Post by Art Prufer » 02 Feb 2021, 18:25

I believe the proposal failed because it was labelled as a change for 3D printing materials, but included changes for non-3D printed materials.
There was a very detailed explanation in Appendix C section 3 around the reasoning for the 3D materials change, but was very little mentioned regarding the change to the existing permitted materials (bolded text below).
3) Reasoning for the proposed IOM Class Rule
The purpose of the proposed IOM Class Rule changes is to formulate a construction materials section of the rules having in mind the original intention of the IOM Class - to permit home built boats to compete structurally with mass produced boats and at an attractive cost – in order to enable good quality hulls to be obtained from a wider variety of sources than at present.
Currently, only a very small percentage of home-built boats now exist in the class. Those that are home built are invariably used by their owner/builders at their own club. Boats competing at the highest level come from a relatively limited number of builders. The class will be much more robust if sources of good quality hulls are available from a larger number of sources and from a larger number of designers.
The relatively small number of builders seen to provide competitive boats, relative to the number of countries where they are raced, means many hulls are imported at a cost that is large in comparison with their value. The absence of locally produced boats that are seen to be competitive works against local growth of the class.
Whereas few individuals have the skills or time to create their own hulls from timber, many are now in a position to create a hull by 3D printing. Currently, according to a recent interpretation, glass fibres may be used in traditionally laminated hulls, and in structures made using additive manufacturing involving resin, but may not be used in 3D printed hulls. This is an unreasonable restriction on a low-cost method of construction which is available to many who do not possess the construction skills of earlier generations.
Proposed class rule changes are permitting the use of glass reinforced thermoplastic material used for 3D printing of the IOM hulls. Fibre materials with modulus of elasticity higher than glass are still prohibited so the boat builders using glass reinforced resin don't need to invest in new materials and building techniques.
The proposed rule is simpler to understand than the existing. It is expected that this rule changes will allow more home builders keen in 3D printing of hulls to build their own or others design. Also 3D printed prototype designs could be tested against the molded hulls before the investments in the plug and mold have been made. In addition, all sorts of gel coats, resins with pigments and other additives as well as additives to thermoplastics are clearly permitted which was not clear in the current wording of the class rules.
I did not see any discussion with the IOM global community regarding this proposed change, at least not on this forum or on any of the other IOM sailing forums.

I must agree with John that the proposed change to all permitted materials (not just for 3D printing) changes the fundamental nature of this section from a closed rule to an open rule, possibly inviting new & unexpected challenges to this rule.

Only fix what is broken. No need to change the whole rule for the sake of some minor wording updates for permitted resin additives.
Art Prufer
CRYA #1189 Can 42
https://westcoastradiosailing.ca

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