Transverse frame calculation

We have to cry with this miserable piece of false imitation of Henry Thoreau poetry?
Don't get up at all, it will be better for your customer.
Daniel

 

I did tweak the rant a bit to make it shorter, sorry Brent, sorry Peers!
Brent uses already half of the server space with his drivel, we must not support that by quoting it completely......

Richard

 

Please state what these advantages are and why.

Agreed.

What do we see you offering as advice…?

Wrong.

We prefer facts not anecdotes as truth.

Oh ok…so, what calculations do you provide as factual evidence to support your claims?

Still waiting to see YOUR maths to support YOUR claim. Not much in way of facts!

Wrong, there is tension and compression. No maths there!

Wrong.

So you say to them, with raw materials and my (yours) time building just the steel work, the cost is $17,000. But if you want a complete finished boat for less, you'll have to have a computer and internet connection? Since these people on the lower end of the market, do not know how to use web site searches to find complete ready to sail boats that are less than $17,000?...oh and if you deduct the raw material costs, they pay you to weld the boat at a cheap rate of $100/ph.

Nice advice for those on the lower income bracket by calling them dense. Since if they knew what to do, they wouldn't ask you or buy your book. Such professionalism….way to go

 

Very prosaic but completely fails to address any one valid point as usual.

You can't even see the classic irony in the "Beware of he who makes money from his advice" statement. Significantly I think people need to beware firstly of your marketing falsehoods.

As for the lifestyle, buying a good used boat is a much better option for your target clientele. Ad Hoc pointed that out very well.

Your ego won't even allow that improving your design significantly will add very little to the time or cost.

Using anecdotal tales as statistics of your 21 to 36 footers to justify structural misunderstanding is extreme deception. Since you now know better, you can't claim ignorance any more. But you keep dishing up the same deceptive and incorrect statements that you been shown are so wrong.

Your marketing thrives on ignorance and deception. Everyone is now aware that you (and others in the Origami backyard cottage industry ) are making a good living that you have to protect with the incessant attacks that you have made time and time again on so many threads and forums.

So if you can't hide behind ignorance what adjectives best describe your activities?

The nature both of your deceptive marketing and your shocking inability to accept a very basic level of understanding of structures is on record for the world to see. It's saddening.

 

A standard propane bottle holds over 100 lbs of pressure easily. If you build the same size bottle, square , out of the same thickness of steel , 5 lbs of pressure will instantly bulge it visibly. That is the huge difference between a rounded shape and a flat sided one. One can easily see the difference in a rounded shape in compression vs a flat sided one. Boil water in a old propane bottle and put a plug in the valve hole as it cools it will maintain it's shape. Do the same with a square, flat sided container the same thickness, and it will buckles as sit cools.
This shows a huge structural difference between a rounded surface and a flat sided one, not minor as some have claimed. Even slight roundedness makes a huge difference.
More to come. Got better things to do at the moment
Going sailing now.

 

Right if you are making water tanks.. there's thou a minor difference compared to boats bcs some of us like to keep the water outside the hull..

 

Ahh..i see we are back to nonsense again. Comparing apples with pears to avoid answering any questions about the baseless claims. Why am I not surprised?

So, more spin and misdirection. Comparing a standard bottle of propane to a boat. Ok, lets look at these bottle of propane and compare them against your boats.

Are these bottles of propane, easy to build, can anyone build them, hell, why not just roll the thing up…it is so easy, it is like origami?

"..The LP gas tank must be constructed and marked in accordance with specifications of the U.S. Dept. of Transportation (DOT). In Canada, the LP gas tank must meet the National Standard of Canada, Can CSA-B339, Cylinders, spheres and Tubes for Transportation of Dangerous Goods and Commission..."**

So, are you boats built to the marine equivalent, Class….er…nope!

"...Have your LP gas tank filled by a reputable propane gas dealer and visually inspected and re-qualified at each filling...."**

So, are you boats “filled” with approved materials of proven marine quality….er…nope!

"..LP gas tanks must be stored outdoors in a wellventilated area and out of reach of children..."**

Well, we see your boats being built outside to the elements in peoples back yards, so that seems fine…and yes, I wouldn’t recommend children to board a boat with no safety certificate nor structure class certificate.

"..Always keep LP gas tanks in an upright position..."**

So, must you keep your boats upright? This is probably correct, since this is the only way to guarantee the stability of your boat since no inclining experiment and no stability book is done to demonstrate the safety of the boat.

Like all your other throw away and grossly misplaced anecdotes. You have no idea what it is you’re saying and the implications of what you are proposing to others. Since the propane bottles are built to an accepted standard and are tested and issued with a nice little sticky labels on the side saying so. Yours are not.

** http://www.managemylife.com/mmh/lis_pdf/OWNM/L0902389.pdf

 

Quote:
[Originally Posted by Brent Swain
...................... Boil water in a old propane bottle and put a plug in the valve hole as it cools it will maintain it's shape. Do the same with a square, flat sided container the same thickness, and it will buckles as sit cools.
This shows a huge structural difference between a rounded surface and a flat sided one, not minor as some have claimed. Even slight roundedness makes a huge difference................]





You already tried the gas bottle to argue for the strength of a curved surface earlier.

The resistance to partial collapse through a vacuum or an external pressure load ( as a boat hull experiences) is entirely relative to the size of the object and the thickness, what radius would that gas bottle be if it was your boat hull, just look at that curvature in the picture below and consider the plate thickness.

Radius(R) is around 10m thickness(t) is about 5mm. t/R is = 5/10000

So your propane bottle to demonstrate the same "strength" relationship if it had a diameter of 400mm would have a wall thickness of 0.2 mm or foil thickness.
Everyone would have had round steel fuel cans collapse just from temperature drop when there's no breather in the lid.
So here's your homework, work out the radius to thickness ratio of one of those cans, it's better than your boat hull by a big margin .

While you're at it blow it out with some compressed air until it has a permanent bulge , now you have some phenominally strong developed curves. In two planes........right?... Nope it collapses even more easily.....funny that

You need to learn some basics you're so uninformed for a boat designer it's frightening.

 

Well, a firehose can handle easyly 1200 psi water pressure, but an empty firehose will collapse the shape immediately. As we can assume, the boat have to handle hydrostatic and hydrodynamic pressure outside.

 

That's some firehose, but you make your point

 

...1200, may be just a typo, one 0 too many, but it seems like oooooooooh, just another non fact from these pages.

 

Hey Landlubber

I'm not sure what you are saying here?

Seems to me that there's a lot of hard facts in this thread and some real effort by people who do know what they are talking about.

Googling "Brent Swain origami boat" produces a staggering number of hits with a lot of disinformation based marketing from Brent Swain.

This idea of his that because there is curvature present you don't need proper framing. Followed by a load of plainly wrong argument, inspires people to build follies like that boat of Paul's posted before.

It's Brent who introduced all the circular arguments and the off topic observations. They needed to be sorted one at a time so it got messy. Now we are back to talking about transverse framing with all the crap cleared away and Brent is nowhere to be seen. Simply because he is wrong.

At least every illogical argument used by Brent has more or less been sorted. Now at least they can be referenced here in the future, so Brent doesn't continually drive the threads into the hazy swamp logic, dished up with lashings of attitude. That has destroyed good threads in the past.

Now Brent's finally nailed to a tree and can't jump sideways, he's just shut up.

Does anyone ( including everyone making $$ in the Origami industry ) doubt that Brent's design (even the the 36) is poorly designed, and has some very poor inbuilt fatigue mechanisms, and is weaker than it could be for very little more steelwork or time?

Does anyone doubt that scaling the 36 design results in a boat that needs transverse framing or bulkheads forward? And the existing poor design details sorted as well?

I'd love to post segments of Brent's plans here with some scathing comments but I can't without his permission....................Brent

 

You can take your pick from 320 right up to 12,000PSI, with metal rings, like origami
http://www.ushosecorp.com/high-pressure-hose.cfm

or

90 to 6,000PSI made from Teflon....just as starters.

Or if you wnat a standard garden hose type
http://www.malcleanse.co.uk/static/PETROL_PRESSURE_WASHER_Guide
http://www.malcleanse.co.uk/static/3_Phase_Electric_Pressure_Washers

up to 7,250PSI or the electric driven one at 14,500PSI

Don't think it's a typo.

If you're only looking at Fire Hoses used by fireman, per se
http://www.richardsfire.co.uk/assets/pdf/water delivery hoses/REFLEX.pdf

Working pressure of a standard 2", or 50mm, hose is 360PSI or burst pressure at 725PSI, some way above 120PSI

 

...what I am saying is that a fire hose is usually about up to 120 lbs pressure, it would be at bursting pressure to be anywhere near 1200.....that is all.

 

I haven't had the pleasure of reading this whole thread or the related matters but it seems to me that there is merits to the various points.

At the Hiswa Symposium in 2008 a paper was presented showing that longitudinal frame members contributed greater to the ship's structural integrity than transverse framing. http://www.hiswasymposium.com/assets/files/pdf/2009/Hiswa Symposium 2008 James Roy Ben Munro.pdf


However, if you look at page 11 of above document, you can see that what was suggested was that the Transverse frame members would be increased in cross-section, greatly increasing stiffness while at the same time reducing their interval, as well as increasing the number of the longitudinal scantlings/stringers.

This is easier to build, less weight, stronger, and more failure mode resistant.

This is something to think about whether building a mega super tanker, a small boat, metal construction, aluminum, GRP sandwich or whatever.

Keep in mind that the distance between "bulkheads" or stringers is very dependent on the dimensions of the boat, aspect, cross section, length etc.

In the extremum, Brent Swain's origami boats are essentially tube structures like an aluminum can.The geometry of them is very strong in a variety of ways, but they have catastrophic failure states.

However, compared to the thickness of an aluminum can Brent's steel boats are quite thick, so you could essentially look at it in the same way (or similar) as a thin skinned monocoque materiel (steel) with a core (steel), so the thickness of the metal itself provides quite a bit of stiffness.

Of course this is scale dependent. For a small boat, this may be enough. Or maybe even "excessive". As always the answer is "it depends".

As things scale up "it depends" probably means, "its not likely". Half inch steel is pretty beefy. But if you made a skin-on-no-frame super tanker that steel skin would have about as much strength as a a 50 foot yacht made of cardboard.

You can build giant mega structures with no internal structure, ala Buckminster fuller, there is a magic threshhold where the object gets to a certain size and it becomes self supporting even with radically thin skin to volume ratios. But there are some big caveats there, and that is for another conversation.

The material characteristics of this structure also introduce a lot of other "it depends" For instance the relative "springyness" of a frameless structure may allow it to survive a blunt impact or other force by just flexing, wheras an internally framed structure may not bend gracefully, and could rupture at the seams, or some other failure mode where the internal frames buckle etc. Essentially it would fail due to its increased rigidity. The opposite could be said though as well especially where the forces are across the entire hull, such as being plunged underwater or in a wave (both compressing against the cross-section and levering the structure like a beam). With no internal structures a buckling could develop very ungracefully. This is perhaps the worst aspect of all. For a framed structure, the object may fail, the failure points may even be the same, but if it is a catastrophic failure it will be gracefully. This is especially true of point loads. If the skin structure is penetrated, the entire structure could collapse by the regular forces it would be under, say its own weight, water pressure, etc. For an internally framed structure, this is less of a problem. Again all of this depends on a million of variables and your design factors, material choices, manufacturing method etc.

Brents' Building "manufacturing" method does have some advantages in it's ease of construction, simplicity of fairing etc, and may even be applicable to boats much larger than the arbitrary "60 feet" (especially since this 60 feet says nothing about the cross-sectional area or geometry of a boat). However, as I noted above, framing would have to be added to the shell. (for boats smaller than 60 feet as well).

Bottom line, boats are very specific sorts of things, they have specific types of requirements, have particular geometries, and experience unique types of loads in regular use and in dynamic failure type situations.

It seems to me there is a lot of things to take into consideration rather than some general rules of thumb about the distance between frame spacing. Whatever you are building needs to be engineered. It may be the case that you need to have a huge crisscrossing internal transverse frames and lots of them to resist massive crushing pressure (like a submarine), or it could be that the skin strength of a boat requires lots of longitudinal support, like a high speed planing hull, maybe a thin skin with a geodesic lattice or honeycomb skin hugging frame gives you the right amount of crush strength but enough flexibility for whatever you are building.

My quote for the day.... there are no right answers, only wrong ones.