Search found 105 matches

by Robert Grubisa
24 Jan 2021, 13:30
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

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 whic...
by Robert Grubisa
07 Dec 2020, 13:22
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

I would like to answer two questions asked by Robert: Hi Antonio, Thanks for providing details and photos! I don't know whether the proper wording for making products using "Elegoo printers" is "3D printing" or not :lol: However, construction techniques are unrestricted, some sort of resin is used ...
by Robert Grubisa
03 Dec 2020, 13:43
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Lester wrote:
03 Dec 2020, 12:29


But the real question remains unclear. I'd like to invite you to reply with a simple Yes or No, and if you really must, a Maybe (!):

Shall cellular structures be permitted in a hull made from thermoplastic?

Many thanks!
No.

Robert Grubiša
CRO 68
by Robert Grubisa
01 Dec 2020, 21:40
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Hi all, I just received this photo from a friend of mine from one of the Facebook groups dealing with the 3D printing of radio sailing boats. Maybe some of them know the source. Sorry, I am not on Facebook :oops: https://photos.app.goo.gl/f8J9wECCrPzEacqr7 I am kindly ask the 3D printing guys to let...
by Robert Grubisa
01 Dec 2020, 21:07
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Hi, Robert: "Regarding your item 1), I don't see how servo/winch trays or similar hull structural items with openings are not in compliance with current IOM Class Rules and CRO proposal. Opening for servo or winch is certainly not falling under "expanded, foamed, honeycombed" as stated in the curre...
by Robert Grubisa
28 Nov 2020, 09:15
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

it is prohibited to use foamed, expanded and honeycombed materials and to construct such features like honeycombed constructions Hi Robert Sure, that is the current situation, I don't think there was any doubt. My understanding is that we are discussing a future situation, where some rule changes m...
by Robert Grubisa
27 Nov 2020, 14:04
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

materials shall not be: expanded, foamed, honeycombed" Just to be a little academic (smile), this phrase must be understood to be talking about what the material *is*, not how it is processed. We are thinking that we ignore all matters about processing, that is, construction techniques, and we focu...
by Robert Grubisa
27 Nov 2020, 13:53
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

I strongly believe that we should not list any construction techniques. They are currently unrestricted and it should be like that. 3D print is just one of available additive manufacturing techniques. We [should] restrict materials Hi Robert Hmmm, restrict materials, de-restrict construction techni...
by Robert Grubisa
27 Nov 2020, 11:52
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Hopefully in the following link you will see examples of non-hexagonal infill that cannot be included in the "honeycombed" definition above, as I pointed in a previous post, and are therefore allowed by the present Class Rules (but excluded by the recent interpretation issued?). https://photos.goog...
by Robert Grubisa
26 Nov 2020, 23:03
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

is the construction shown here (regardless of building technique used) honeycombed? For me, except for the 100% and 0% images, yes, all these are 'honeycombed'. Why such construction need to be permitted regardless of construction techniques used? Not entirely sure I understand your question. For m...
by Robert Grubisa
26 Nov 2020, 20:50
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Hi Robert From the point of view of the rules we wish to make, I think we distinguish between solid materials, and materials with voids. Honeycombed, foamed, expanded, micro-ballooned, infill less than 100%, all these words and concepts refer to materials with voids or ways of creating materials wi...
by Robert Grubisa
26 Nov 2020, 19:16
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

I've completed a spreadsheet which calculates values of stiffness, strength, and weight to allow what-if comparisons of various materials in hull construction. I've updated the document to explain it, give some sample calculations, and suggest some conclusions. I repeat these here: Permitting honey...
by Robert Grubisa
26 Nov 2020, 17:10
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

HI Robert, Thanks for the reference to the rule change, however, it is still not an issue, as gel coat is a type of resin (permitted) and resin may be coloured. The other references such as use of fillers still apply. John Hi John, This is one of Q&A which is questionable: ------------------ Questi...
by Robert Grubisa
26 Nov 2020, 15:48
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Thank you, Robert, noted. I understand though that out of this discussion glass infilled thermoplastics may be allowed, and that is part of this debate. In that sense, I would like to point that 3d printing with UV photoactivated resins, the growing new 3d printing technology (for instance with Ele...
by Robert Grubisa
25 Nov 2020, 21:48
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Hi Robert, You wrote Your proposal is not solving following items, related to the "classic" moulded boats. According to the current IOM Class Rules: a) Gel coat is not listed. Is it permitted? b) Coloured pigment is not listed. Is it permitted? c) Is a filler made of resins with some filler (micro ...
by Robert Grubisa
25 Nov 2020, 20:40
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

The question of allowing glass fibre as an allowed material for thermoplastics could be achieved by a motion to reword D.2.1(a)(3) which says (3) Resin, which may be coloured and/or reinforced with glass fibres, but if it were changed around such as (3) Glass fibre. which may be bonded with resin, ...
by Robert Grubisa
25 Nov 2020, 17:10
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Other thermoplastics with glass fibers poweder are also available, and are also permitted materials, so again no need to change the rules. In summary: keep rules as they are except clarify that 3d printed hexagonal infill is not a honeycomb material . Hope this helps. Antonio Hi Antonio, Thermoplas...
by Robert Grubisa
24 Nov 2020, 18:01
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

What if [...] the hull with different thickness of hull skin [...] advertising and selling such IOM boats as the state-of-the-art? Hi Robert I think looking at specific scenarios is a good way to explore the issues we have. In this case, I think a fragile super-light hull with different skin thickn...
by Robert Grubisa
24 Nov 2020, 13:51
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Conclusions We can 3D print a nice honeycombed (20% infill) hull in g/f nylon filament with the same stiffness and same weight as a pre-preg S-glass hull but it'll have one third the strength. So this is not going to obsolete the fleet or threaten anyone with a nice g/f hull. This is simply due to ...
by Robert Grubisa
23 Nov 2020, 21:31
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Yes, just using this open forum to, as I said, 'come to an agreed wording and get the motion passed'. Seems to be working so far, an open forum where the more experienced 3D printing home builders can have a voice and not just the commercially involved or a selected few friends. Must admit, some gr...
by Robert Grubisa
23 Nov 2020, 17:33
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Hi everybody, and thank you Graham for the initiative. I personally like to explore the different possibilities that this technology offers; testing materials, techniques, etc. This desire to experiment and develop I think is shared by many and is conducive to creating more hobby and activity in th...
by Robert Grubisa
23 Nov 2020, 17:32
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Reasoning for the proposed IOM Class Rule are given here for easy reference as submitted with the proposal. Maybe all interested are not aware of it: The purpose of the proposed IOM Class Rule changes is to formulate a construction materials section of the rules having in mind the original intentio...
by Robert Grubisa
23 Nov 2020, 17:27
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

This is the response to misleading criticism of CRO IOM CR proposal 2020 which Graham Bantock sent to the IOM ICA World Council members before the voting: (I am posting it here with his permission). The CRO IOM NCA forwarded to me a misleading posting on Facebook that criticises the CRO proposal co...
by Robert Grubisa
23 Nov 2020, 17:20
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

So a new rule proposal may look like 2D.1 (8) Thermoplastic, which may be molded, containing only permitted materials 8.1 for a 3D printed hull, any PLA (or abc) based thermoplastic with any additives (except -x,y,z) are permitted. 8.2 there are no restriction on infill nor any internal reinforceme...
by Robert Grubisa
23 Nov 2020, 17:09
Forum: General IOM
Topic: HULL MATERIALS....3D Printing. Croatian Motion.
Replies: 90
Views: 5503

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

Let's all have a discussion in the correct place, the IOMICA forum, and not Facebook or secret emails, yes, an open discussion with even luddites included. My understanding is that most want to embrace the new 3D Printing technology but the wording of the recent Croatian motion was not to everyones...
by Robert Grubisa
11 Mar 2015, 14:58
Forum: Class Rules
Topic: What "..shall pass through a 20mm, ring gauge." BOOM F.4.5
Replies: 30
Views: 23837

Re: What "..shall pass through a 20mm, ring gauge." BOOM F.

Please be informed that the Interpretation 2015-IOM-1 has been published on Technical part of the IOM ICA website.

Best regards
by Robert Grubisa
11 Jan 2015, 16:46
Forum: Class Rules
Topic: What "..shall pass through a 20mm, ring gauge." BOOM F.4.5
Replies: 30
Views: 23837

Re: What "..shall pass through a 20mm, ring gauge." BOOM F.

Note that GBR NCA asked for interpretation on the IOM Class Rules regading fitting under the main boom.
See: http://www.iomclass.org/wp-content/uplo ... n-boom.pdf
by Robert Grubisa
25 Sep 2014, 23:14
Forum: Class Rules
Topic: Interpretation - jib boom topping lift restraint line
Replies: 3
Views: 5464

Re: Interpretation - jib boom topping lift restraint line

Emergency class rule change is posted on the Class Rules part of the IOM ICA website.
by Robert Grubisa
11 Sep 2014, 19:50
Forum: Class Rules
Topic: Interpretation - jib boom topping lift restraint line
Replies: 3
Views: 5464

Re: Interpretation - jib boom topping lift restraint line

Interpretation is posted on IOM ICA website front page and under "Class Rules" part of IOM ICA website.
by Robert Grubisa
23 Aug 2014, 12:50
Forum: Class Rules
Topic: Interpretation - jib boom topping lift restraint line
Replies: 3
Views: 5464

Interpretation - jib boom topping lift restraint line

GBR NCA asking for interpretation on IOM ICA Class Rules regarding headsail boom topping lift restraint lines are posted here:

http://www.iomclass.org/administration/technical/

Best regards