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Author Topic: how do i build a hull with no plans.  (Read 6528 times)

ZIPPY

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how do i build a hull with no plans.
« on: August 09, 2009, 08:05:43 pm »

Hi guys,can anyone tell me how i can build a hull with no plans.I know its easy if your designing your own boat but what if i had a boat in mind but only had photos.I have been reading a few topics on the forum and some mention high density foam for sculpting,but then i thought what if there is a model kit that has a verry similar hull coulkdnt i just copy the structure from the plans and enlarge the whole lot and then plank the hull.Could you give me your exspert advice on this.I have enclosed a picture of my next project and do have pictures of the hull but dont have a clue where to start with no plans.
                                                             Cheers Andy. :-))

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andygh

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Re: how do i build a hull with no plans.
« Reply #1 on: August 09, 2009, 08:12:26 pm »

If you're not worried about pinpoint accuracy your idea sounds pretty good  :-))
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cos918

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Re: how do i build a hull with no plans.
« Reply #2 on: August 09, 2009, 08:15:53 pm »

Hi Andy . There are several ways to attack this.
1.wright to the shipping company or the shipyard enclose photo of previous build to try and convince them you are a guinea molder and not and Ebay ,get and sell person.
2 Join the Off Shore society they might have links or people who may have contacts.  http://www.osv-society.info/
3 Find has many photo of her/sister or similar ship. Use these to make line drawing.
4If there is a kit or a similar kit you could copy or use to make plans.

Using foam to build the hull will allow you more sculpting that a plank on frame route. Then use the foam as a mold for fiberglass.

To help judge size take a door way as a given size and use that to judge the rest of the photo .

John
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ZIPPY

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Re: how do i build a hull with no plans.
« Reply #3 on: August 09, 2009, 08:25:29 pm »

Thanks for the prompt reply.So you two would go with the styrene plan would you.You mention a line drawing,well i read a previous comment you did John,i think it was you.It was about a programe on the net for designing hulls,i have downloaded that but cant make head nor tale of iit.Is it not possible to download images of a hull and cut it into sections for printing sort of like putting the hull into a bread slicer and using each slice as a template or is that going a bit technical. :-))
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cos918

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Re: how do i build a hull with no plans.
« Reply #4 on: August 09, 2009, 08:38:01 pm »

Hi Andy the software I was on about. The have been several post on here were people have use it. I think Ian {boatmadman} has used it.
http://www.modelboatmayhem.co.uk/forum/index.php?topic=17422.0
What it can do I am not to sure. I think it lets you draw a hull and you can pull it here or there IE like sculpting but on a computer. From the you can print. I have only read what people have post and do not have this software yet.

John
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ZIPPY

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Re: how do i build a hull with no plans.
« Reply #5 on: August 09, 2009, 08:42:36 pm »

Thanks John,i think i will stick with the foam idea it appears to be the most favoured idea.
                                                    Chers Andy :-))
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boatmadman

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Re: how do i build a hull with no plans.
« Reply #6 on: August 09, 2009, 08:44:47 pm »

Andy,

The design software is delftship, its free. It takes some work to get used to it, but in my opinion, its worth it.

It allows you to design a hull from scratch, check the hydrodynamics, resistance etc. You can then print off a lines diagram from which you can build the hull.

I am currently building a Bourbon Orca, here,  http://www.modelboatmayhem.co.uk/forum/index.php?topic=17422.0 which I designed using this software, printed off the lines and worked on from there.

Ian
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ZIPPY

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Re: how do i build a hull with no plans.
« Reply #7 on: August 09, 2009, 08:56:17 pm »

Hi Ian,yes thats the free download i have got.The problem is i dont have a clue what to do with this software.When i open new project and it takes you to a list of demos the first one is really what i am trying to achieve.Is it not possible to use that 3d image and have someone cnc it out of a styrene block.But if it was to exspensive i wouldnt be doing it that way.The problem is i like verry big boats and want this hull to be around 6ft in length and cant imagine sculpting it out of styrene.
                                               Cheers Andy :-))
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boatmadman

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Re: how do i build a hull with no plans.
« Reply #8 on: August 09, 2009, 09:04:36 pm »

Andy,

If you open file, new.. you get a window for a new model. Here you input length, breadth, draft, and number of vertcal and longitudinal stations. As far as cnc is concerned, I may be wrong, but I dont think the free version outputs a file suitable for this. Umi tried this for me for my current build, but it wasnt easioy obvious how to do it, so I reverted to a printout and cut and paste the profiles onto plywood.

I too like big boats, my current is 1.2m, ok not as big as yours, but still a good size.

Ian
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ZIPPY

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Re: how do i build a hull with no plans.
« Reply #9 on: August 09, 2009, 09:11:29 pm »

I will give it a try Ian.Is it not possible to split the hull into sections and print each one off and use them as templates for the hull.
                                                     Cheers Andy :-))
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boatmadman

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Re: how do i build a hull with no plans.
« Reply #10 on: August 09, 2009, 09:12:40 pm »

Andy,

Dunno if you can split the hull, will have a look and get back to you.

Ian

PS. I cant see a way to do this, but I have posted a question on the delft forum.
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ZIPPY

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Re: how do i build a hull with no plans.
« Reply #11 on: August 09, 2009, 10:01:12 pm »

Cheers Ian,thanks for that.It will be interesting to see whats said. :-))
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kiwi

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Re: how do i build a hull with no plans.
« Reply #12 on: August 10, 2009, 01:33:05 am »

Hi, Delfship outputs ".stl" files as one of its options (including the free one). This is a 3D file which can then be imported to other 3D software for splitting into sections.
Or into some CNC software direct.
All the information for lines (buttocks, hullplanes, waterlines etc are on the "lines drawings" just make sure you turn them all on first), and all these can be specified to whatever spacings suit your method of building. These lines drawings can be printed out at whatever scale you require and then templates etc cut from them and , well the rests upto you

cheers
vnkiwi
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ZIPPY

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Re: how do i build a hull with no plans.
« Reply #13 on: August 10, 2009, 08:56:06 am »

Hi thanks for that but where do i find these stl files are they a seperste download to the software i already have.What sort of soft ware would i need where i can put any picture into the project and it will automaticlly scan that object and show its construction inside and out,or am i looking at thousands of pounds for that kind of software.
                                     Cheers Andy. :-))
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boatmadman

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Re: how do i build a hull with no plans.
« Reply #14 on: August 10, 2009, 09:03:35 am »

Hi,

A reply on the delft forum suggests export the file as a dxf file to a cad program, and use that to produce individual profiles for the stations. I cant help any further on this, as I export the lines diagram to printer, make as many copies as I need to give me every station, cut them out, stick to plywodd and attack with the jig saw.

Ian
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ZIPPY

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Re: how do i build a hull with no plans.
« Reply #15 on: August 10, 2009, 10:26:08 am »

Thanks for all your help Ian but im still none the wiser on this software. {-) {-)
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Colin Bishop

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Re: how do i build a hull with no plans.
« Reply #16 on: August 10, 2009, 11:10:58 am »

Quote
not possible to download images of a hull and cut it into sections for printing sort of like putting the hull into a bread slicer and using each slice as a template or is that going a bit technical.

What you are describing here is a "body plan". You can Google this for a more detailed explanation such as here: http://www.modelshipwrightsdatabase.com/Articles/07InterpretingLineDrawings.htm

Learning a CAD program just for one project seems like overkill!

If you buy a kit of something that looks similar it will probably come with the hull ready made so the drawings will not be sufficiently detailed. You would have to take the dimensions off the hull itself which could be timeconsuming. It is also a rather expensive way to go about things.

As has already been suggested, your best bet is to write to the owners/builders but it is possible they won't give you the information on the grounds of commercial confidentiality. For a project like this you do really need some decent plans, "bodging it" is likely to prove a disappointment.

Colin
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boatmadman

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Re: how do i build a hull with no plans.
« Reply #17 on: August 10, 2009, 11:13:34 am »

If you have no plans for your boat, you really only have two options (I think)

1.  You need photos to show plan, elevation, bow and stern. You would then need to label each picture with reference points from which you could take measurements and develop a lines diagram. You would have to find a reference point for size, such as a doorway and work the dimensions from there.

2. Design your own. This really isnt as daunting as it sounds. If you have a good range of photos of the boat and the general specs such as length, beam, draft you can work from that.

Take a series of relevent dimensions from the pictures and using the scale proportions of the length of the ship in the photo to the real length you will be able to locate key features on the ship. EG in photo, measure distance from bow to front of superstructure, scale that dimension to full size, then scale again to the size you want to build at.

If you decide to go this way, when you are working the design up, I have found that if it looks right then its ok. Also, who is going to criticise the model if there are no kits or plans available?

If you decide to use delftship, I would recommend you design at full size dimensions, and when you are happy with the design, scale it down using the scale function. This way, if there are any lines that are not perfectly fair (and in my experience there will be unless you buy the pro version with auto fairing), when you scale down, they are much less obvious.

Hope this helps.

Ian
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Circlip

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Re: how do i build a hull with no plans.
« Reply #18 on: August 10, 2009, 03:18:26 pm »

How do scaling down Full size ship plans work in the respect of displacement and stability??


  Regards  Ian.
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boatmadman

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Re: how do i build a hull with no plans.
« Reply #19 on: August 10, 2009, 04:37:15 pm »

Ian,

Good question, I suspect (and will no doubt be put right very quickly) that displacement reduces with the cube root of the scale.

As for stability, well, I just add weights and foam to make the model stable - seems to work ok.

Ian (no naval archtect :}
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ZIPPY

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Re: how do i build a hull with no plans.
« Reply #20 on: August 11, 2009, 08:17:14 pm »

Thanks for all your advice guys,i have decided to find a model boat that resembles the boat im building and enlarge the plans for the hull which i have already done.From there on i will probablly need to modify the hull a bit with filler.I do have one more question,when i use my templates for the frame work what type of wood should i use as the boat will be about 5ft in length and 18" at its widest.Do i need to use such exspensive plys like birch ply and how thick would it need to be for the outside to have plenty of glue surface.I was also wondering if its possible to make the frame from a thick rigid plastic which is cheeper than buying birch ply.Could i use 3mm thick plasticard for the outside cut into strips and then resin the inside of the hull when finished. :-)
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boatmadman

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Re: how do i build a hull with no plans.
« Reply #21 on: August 11, 2009, 08:49:25 pm »

Hi,

I use 6mm external ply from B&Q for the framework, spaces about every 100mm (actual spacing depends on the model).

Not sure about using plastcard planking, I suppose in theory it should work ok. I am sure others will express opinion on that.

Ian
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ZIPPY

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Re: how do i build a hull with no plans.
« Reply #22 on: August 11, 2009, 09:05:50 pm »

Thanks for that Ian,i have 6mm ply from b&q but when you bend it slightly you can here it splitting and its only three layers thick but the midle layer is like a sponge and im wondering whether the glue is just going to soke into the wood and not adhere to the wood enough.The two outside surfaces are fine im just concerned there wont be enough surface area for gluing such a large model together. :-)
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Shipmate60

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Re: how do i build a hull with no plans.
« Reply #23 on: August 11, 2009, 09:09:07 pm »

ZIPPY,
There are some very good threads on planking and double planking.
All materials and pics of how it was done.
Just use the search facility at the top of the page.

Bob
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ZIPPY

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Re: how do i build a hull with no plans.
« Reply #24 on: August 11, 2009, 09:13:24 pm »

Thanks for that Bob, :-)) i will have a browse.
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