MINI-Mini

I'm a young student working for my ideal little boat for summer, i' m planning something about 5 metres similar to a mini built in radius chine, on web i didn't find something similar for free... i'm using Rhinoceros And Autocad in planning ... but i have some troubles on making an hull marine... how is better i analize hidrodinamic? is better some CFD software ? I have to build million of models? or there is a way less complicated? i don't know any boat desiner and i don't know the best way to proceeed ... wen i will end , if it will come out a validate design i'll publish for free
here an idea of boat in dwg(2004) ...and a rhino render ispired from a mini for anyone who want to discuss the project i can send the entire cad file
thanks and sorry for my bad english

 

Look at www.RhinoMarine3D.com
You can downlaod a demo-version.

 

ciao Ciccio, I'm italian too, there's a boat wich is a downsized simplified version of a mini, she's called IDEA19, building plans are avalaible at www.nautikit.com, take a look at her , send me a private message in this forum if you're interested in that boat, otherwise i can give you an helping hand to develope your project.

ciao
Mistral

 

I'm curious, why not build a Micro Cupper instead, so you have someone to race with?

I think Phil Morrison (designer of world champion International 14' skiffs and one of the best dinghy designers of all) designed the Speculation, a Micro Cupper for hard-chine ply construction, many years ago. It would still be a very competitive Cruiser or Regatta division racer I think. It looked like a really nice boat and quite similar to your rendering.

 

it's a little different concept wich takes to slightly different boat; micro cupper are suited for short buoy racing and costal cruising, this boat is suited for transmediterranean cruise, and medium distance races, she has a liferaft storage, sturdy rigging and decent self-righting ability; but, most of all, micro cupper are seldom seen in Italy, I guess they have a good class activity in eastern europe; there's been a couple of persons who tried to bring class back to life here in Italy during 90's, but with very poor results; I consider this project more as a training boat; something really funny to sail and relatively cheap, but enough seaworth to give you a good training in medium-long range cruise/race, single or doublehanded, an intemediate step to gain a decent experience before entering the world of minis; anyway it would be interesting to have a european circuit wich gather all these micro-boats!
the first IDEA19 will be launched at the end of March, i think i'll put some videos on the web and for sure I'll get reliable polar diagrams to compare this project with the other existing ones, so stay tuned!!

fair wind
Mistral

 

Ok, good reasons.

I didn't realise the Micro was dead in Italy, I must have just heard of the attempts to get the class going again.

I quite like that Idea 19; not as over-canvassed and complex (and expensive) as a Mini.

 

Thanks to all for goods suggestions, and sorry for my assence
At the moment i'm using rhino to veryfy hidrostatics in different angles , i'm going to verify hydrodynamic (as possible for my poor knowlege) and this week end I'll send results.
I already know the boat IDEA 19 and i'm sure of the success of the boat,it really looks good ...but i prefer working on a personal project, studing for learning something more about sailboat design.
at the moment i'm having a brainstorm around cheapest and fast kind of construction method compatible whit the design and the possibilties of a student
I've never heard nothing about micro i looked on the web and it looks interesting

i hope we'll see thogheter the growing of this little open sorce plan during the coming weeks....

exuse my bad english

ciao ...

 

ok Ciccio, so good luck, anyway if you like to get some advice and confrontations i'm avalaible!!! cheapest way is probably monolithic GRP but you need a mold, so at least it's not so cheap for a one-off design; probably plywood Radius chine is a good option but i don't like its conditioning the design; if you like to take a look at IDEA19 i'll be in Treviso at the end of March for the launch, send me an e-mail if you like.

for CT249: you perfectly focus the boat, a downsized simplified and chepaer mini.

Mistral

 

hi to all
at the end i adjusted something on the hull and unfolded the entire hull in two pieces i'm valuating an inusual way of construction; in origami way but with plywood instead aluminium or steel , i think it have some vantage it would use about 80%less of glass fiber , woul be fast and easy to shape. i build a model and it looks very solid ,i never seen something similar,as soon i can i'll put some photos ...wath do you think about?

 

here a bad photo and an example of origami building

 

Ciccio, thanks for posting my YAGO template
The folded model in your picture was not done from that though. From what I can see, your darts were cut quite short which gives you very long conical sections fore and aft, this will not work out nicely I fear. You will get a very low Cp like that because on the long conical section there is not enough tension and compound curve and they will run almost straigth to the ends, leaving you with very little volume there.

Also, and in spite of my own interest in origami folding techniques, for a smallish boat like that in ply or GRP I do not think that origami is the way to go. In that size and material, there are many combinations of stitch&glue, basket moulds, radius chine and so on that will produce very fair hulls in a short time, and even a fully developed round GRP hull build one off on on scrapwood frames without mould is easy and cheap.

BTW, why would you save 80% (!) of fiber with origami? The fact that you fold the skin doesn't change anything as far as scantling is convcerned...

 

sorry i didn't remember were i found that image and i still didn't prepare one mine, so i just have done and here you can see the developed hull.
i designed it in rhino as an hull composed by portions of conoid and if the CB should be low and the boat flat as i put togheter panels( as in the previous photo) , once glued two wooden reinforcement and 3 bulkhead it seems to me it goes better. also become so solid that you can see in the picture
a test with 4 kg (4000 kg!!scaled) .
about the use of glass fiber exuse me if i haven't explained , i compared this kind of constructon to a tradictional switc and glue where there are lots of panel to glue witg glass fiber instead of here where the use of glass fiber is
limitated cause there are few edges . if you misure on the developed model you'll see there you can use 80% less of glassfiber.i looked at the metods you suggest , but in all you have to make more cut and glue more pieces or have to build a structure to keep the shape...
making the model i undestand lots of errors and correction i have made to the model but at the end does look so bad this kind of building in plywood?

waiting for your response

good bye and exuse for my bad English

 

No problem

Yes, there are less joints, so on these you would indeed save a a little bit of material. But this does not represent a significant overall saving. A boat built origami is practically the same weight as another one built, say, stich & glue ply, if the material and scantling is the same. And there is really no reason why it should not be.

Origami as such does NOT save on structure - it saves on temporary jig and structure needed for assembly, but otherwise scantling is the same. the necessary scantling of your boat is decided by stresses and materials, not by the method to put it all together.

If for example you build a strip planked hull over scrapwood frames and then tear them out it's the same weight and material-shopping (apart from the scrap stuff that costs next to nothing anyway) as the same hull folded without any jig or temporary frames the origami way. What counts is that your finished empty shell has the proper strength and stiffness.

The other thing you need to be careful with is not to let the building method dictate your hullform into something that you don't really want. On your pictures it looks as if you have a very straight long and deep forefoot, and at the same time a sharp rise aft, with a pronounced bend where your vertical dart cuts come together. Yes, it folds ok, but is that really the hull you want?

Origami is an interesting, simple and fast assembly method, but because the hull is only a small part of the entire project anyway, it's really more interesting for bigger boats, in metal, where you really can save enough time to notice the difference.

On a small boat the time saved is not so important, and especially if you have some very much optimized, mini-style hull in mind I would go for the little extra work to build a round hull in strip or sandwich.

 

PS...I forgot: if you want me to have a look, send me your rhino file, maybe I have some ideas for the origami-template, ok?

 

ok, i just sent to the mail of your website the file ... i agree there is something strange with the model, but i think that plywood may be still tortured to adapt shape to other bulkheads.
strip or sandwich looks to me quite complicate cause i'm not so experienced and i think that the only alternative for my ability is switch and glue and i ask myself if origamimay be better of this and wich compromise may be reached to optimize the hull form developed in origami .
thanks ciccio