Origami steel yacht construction

Alex- oh crap i didnt realize this was your thread--my humble aplogies-
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m&m ovenden- your wrote: I want to cruise (and have)
I want to live on my boat (and have)
I want to live on my boat in cold climates (and have, frozen hard in the ice)
I want a strong boat (no worries there)
I don't have loads of money (never will)
I like thinking KISS
I'll probably only ever own the boats I'll have built
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I could not have said that any better--im obviously not rich either- so your last statement i quoted from you- was particularly relevant for me. This is what intrigues me about Brents methods is that - if they do work - and apparently they do- What a great cost effective way of imho of doing a steel boat.
btw I spent half my time in ottawa growing up- the other half in muskoka-- are you at the Britannia yacht club at all? or near there? i grew up right near Britannia beach. so i know that area well..

Troy- too bad about those gals. I agree- i dont understand why you would want to hide the fact that its steel--perhaps i might want to hide the fact i had a ferro-boat if i did- and i am a total advocate for FC. the only reason being Fc is not reputable but SHOULD be(again just my opinion). I have seen some steel boats that were as fair as fiberglass. another method that seems to work well is Ken Hankinsons Fred Murphy tug design--its called shrink wrap steel. thats a pretty fair hull too..light framing and only 11 gauge plate! and although ive never seen one- they are supposed to be very robust. The only reason i didnt build one was because the hull had canted inboard sides which i dont like for "towing on the hip" and it didnt have room enough for my 36 inch dia prop.
the glen-l office is down there in your neck of the woods. ever been there? if i ever go to Cal, i am going to do Glen-l as a tourist attraction since i built a couple boats from them.

 

Don't feel sorry for the gals, tugboat. They knew exactly what they wanted, and did a bang-up job of building it. I was quite impressed, even though what they wanted isn't my cup of tea. And I suppose that really, finishing off the inside of a steel boat isn't that much different from finishing off the interior of a brick house.

Never been to Glen-L. You're right; it's my idea of a tourist attraction, too.

 

Claiming my boats are sections of pipe with the ends closed is a lie, and hardly qualifies as sticking up for me. All lies have to be challenged

 

The main reason for covering the inside is insulation, not neccesary in the tropics ,altho I was on an uninsulated boat in Mexico once. Very noisy. With sprayfoam they are far quiter than most other building materials. For the low budget cruiser, you can move aboard and cover the insulation at your liesure while cruising. Once couple I know did a circumnavigation without getting around to covering the spraty foam .They said "We kinda got used to the cave look."

 

tug

A lot of Brents belligerance lately on this thread and the transverse framing thread is because he is wrong on his structural arguments and won't admit it.

He thought that an arc was an arch, that the longitudinals never went into tension and that transverse frames are adequately replaced by a deck. He has no idea about buckling as a failure mode and argues everything on a basis of tensile strength. This is totally contrary to an engineering structures approach.

It has been shown clearly enough that his boat construction methods produce much weaker frames than traditional construction methods. So they are fast and simple but they are weaker not as he claims, stronger.

So all you can really take from that is that his method appears to work ok for 36 footers but be very careful of buying into his supposed structural dis-information. They don't hold water and they will not scale as he claims.

McNaughon (landing boat school (I think)) came to a similar conclusion a while ago when he actually bought Brents book. He said then that the very limited structural explanation was totally wrong.

 

LyndonJ-i am reading your post with an open mind....one of the things i personaly have noticed in my life--is when a new method comes out it really get opposed until it becomes accepted. even by the authorties on the matter. im not saying your incorrect--my only questions are-..even if this only does work for a certain type of hull in a specific type of development(actually i dont think conical- and i believe other boats have been built other than sailboats), hasnt Brent and many others put their boats through some rough situations? and if so--doesnt this account for anything?? one other question to think about is--even is the hull isnt as strong as a framded hull--does it really matter all that much? and how much less strength would be probematic?...perhaps if your correct- the strength reduction would be just negligible?...I do trust Brent when he says he has logged many thousands of miles on his boats--i look to more empirical and practical results in real world situations to test out a design....just some thoughts...
hope your boat projects are going well ....

 

The method is neither new or unique to Swains boats. What is contested is not the method as much as the lack of methodology in the decisions made in the design process (as well as the erroneous bases the decisions are made on). Authorities would accept and stamp those boats if they fulfill requirements. Requirements are not about frames or no frames but about the integrity of the structure and that is to the designer to provide required information.

Of course any intelligent person is willing to recognize that and take it into account (to a certain point). Human kind grew to what it has become threw experimenting...successes and failures. Our modern society though has exploded in creativity and evolves at much higher rate and much lower failure by applying modern techniques and knowledge. Norms and regulations are based on a already acquired knowledge and are there to force creativity threw a safe path. Yes we rather often feel they are a pain in the ***, but no they're not there to put a brake at creativity there to reduce fatal failure. What Brent refuses, is to accept that there is merit to this.

Exactly! So how much less strength does the structure have to start with?

Murielle

 

I hear you Murielle, do you know by any chance-how this is done? how we can measure strength on a framed vessel? the methods i know are using youngs modulus, relative to other materials. buts thats only for the shell thickness. or using the astm standards on steel? how DO N.A's calculate this empirically??.there are so many ways to build a boat i find, that perhaps finding some standardized equations for calculating actual strength for each individual method would be very difficult??

 

Lots of fun to be had with ABS standards to start. Section modulus wonderland.

Tugs,
I know you are exploring the origami option to optimize ease and cost on your project. Honestly I don't see how it really saves that much. The most expenses on a steel boat are not on the hull. Over such project, a couple thousand dollars are not really relevant. Most expenses will be on paint, sandblasting, suiting up your boat. Time? Maybe when building a boat was lofting full size on the floor it added a bit more substantial drag but with computer files and NC cutting that's not true anymore. So apart from assembling a few ribs where's the difference in work load between frameless and framed? The deck will have the same detailing, you'll need masts steps, engin beds, threw hulls, bulkheads, tanks....same for both. The amount of welding? Come on, if it takes you that long to weld up a seam that's it's that much of an issue...checkout your set up. The real time eater on a boat construction is the fitting out, not assembling a hull.
I should point out that with nc cutting $3000 (can) got me detailed cut ribs, including materials for a 60000lbs boat. How much would be the extra plate thickness compared to frames? What saves money and time is doing things smart not cutting corners.
When money is not there, the only way to reduce costs is to build smaller. Than you'll save on surface (blasting/paint, insulation), you'll save on fitting of components that are relative to your displacement/size (anchors, chains, engine-well that only to a certain point-, sails-for sailboat-, fuel, ballast....).

Think about it well. Is origami attracting for the right reasons? Brent has great ideas for some ways around certain expensive components on boats. It's ugly but his windlass has the credit to be functional and cheap to make for an example. I'll give him credit for a bunch of little tricks he gives to cheap out, some are really clever. ...but when he claims his building method is buck saver? I don't buy it.

Murielle

 

It's not a new method of acheiving structural rigidity. It'a just a method of fairing the plating. Only Brent argued that it made stronger. That would have been nice but it's based on misunderstanding.

Unfortunately it makes the resulting frame floppier. Thats a fact. Brent beleived it made it stiffer, that beleif is esaily shown to be wrong and clearly has been.

Now the danger (once again) is that sommeone preaches a message that this method is lighter easier and stronger and will work on boats twice the length without scaling the actual real structure that keeps it intact.
In reality for the boat to be as strong you'd need to scale the plate and frame dimensions along with the displacment (or thereabouts).

The loads are not linear with length.

If you don't want to learn from those of us ringing the alrm bells here, then print these threads out, take them to any structural engineer and ask them to comment from first principals.

 

LyndonJ - no i get what your saying--isnt it true very big name designers have done similar things .i.e bruce roberts has some frameless designs? i believe the 26ft tom thumb for one?--not saying your incorrect --i am reading all posts with an open mind...
see for my project--a tugboat- wieght is needed to bring it down close to her dwl. so larger plate is an advantage here. as for framing etc---if built convemtionally-this design would need three ft spaced transverse and longitudinals at about 12 inches C.C. - but thicker plate could not be used for framed systems it would be too heavy??? thicker plate- doesnt that mean more ductile resistance? ..

economics--true there wouldnt be much savings--only savings
with time perhaps- but it would still be a bit cheaper...the only thing that scares me with this method is "what if a bend a long panel wrong and mucked it up? then im in a heap of trouble..but thats about it...all input is greatly appreciated...i know it sounds like im defending Brent--and even if i dont go with frameless-- i tip my hat to him for effort and -id probably trust sailing one of his boats. but thats just me...

 

Classification societies amd regulatory bodies are attacked by Brent for not accepting his structural arguments.
I can never understand why he made it up himself and never actually consulted an engineer to check his reasoning.

But an honest open approach shouldn't involve retreating into rhetoric.
He needs to accept that his small boats are ok and that we all applaud his motivation and drive and achievements.
But I think he will walk a path of self destruction if he keeps beating his head on the floor. Stubborn drive can make great achievements but that same stubborness will destroy as well.

If he just said now "oops I appear to be wrong on that point, lets add a few transverse frames on larger versions " he'd keep his mojo.

 

I'd stick to conventional methods, you'l have an asset then that you can relise when you sell. It's easy enough to put in some frames and bend 1/4" plate around them. The resulting stiffness and strength will be much greater. It's not how much material you put in a structure that makes it effective, it's where you put the material. If youuse thicker plate the framing can be further apart by class rules. So you can get a higher puncture resistance if you want, but I'd still put the required framing in.

 

a webframe yesterday