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  #2571  
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Re: Pros and cons of steel sailboats

Here's a pretty typical 'workboat' style yacht found in Europe.. I think this boat has a lot of charm.. Steel, if not iron!?!

The name roughly translates (I think) to 'never would have believed it'...

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Re: Pros and cons of steel sailboats

I'm always partial to tugs. I like to do tug cartoons. There can be a nobility to a good tug. These boats are perfect examples of how steel workboats can be beautiful. All it takes is a designer with an eye.
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  #2573  
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Re: Pros and cons of steel sailboats

Spike worked for a Volvo "recycler" when he was in high school. I bought him a nice Volvo station wagon. He bought himself a 1957 Volvo panel wagon. He got it for $1,000 and put a lot of work into to to get it running again. The body was pristine but needed paint and the interior was a wreck. It was a brute of a car. When he moved out he had no place to keep it so he sold it to a Volvo mechanic in Ballard for $4,000. He eventually bought a new Scion "Box". He never really bonded to the Scion. Spike preferred cars that needed constant attention. He bought a VW bus and that took care of the constant attention need. He seldom drove the Scion after he got the bus.
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  #2574  
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Re: Pros and cons of steel sailboats

Quote:
Originally Posted by MikeJohns View Post
Hi Smack

Yes VDS sold plans to pro yards and home builders alike. They are very common designs in some parts of the world. Easy to build and some chine based frameless designs that go together quickly. And well engineered.


Alloy origami, look here:
Origami Magic Not Brent's designs but origami boats. Nothing about them being frameless and that boat would be pretty floppy without significant frames, girders transverses or bulkheads of some sort.


JeanMarc 50
The above 50 footer is the 55 footer that BS just rambled on about as vindication of his claim that his boats would scale to 60 feet without frames.

Much nicer looking hull than a BS boat.
I suggest you experiment with sheet metal models, to further your comprehension of how shape eliminates the "Floppiness" you fantasize about.
You can learn a lot that way. What supports what, quickly becomes self evident with such models .
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Re: Pros and cons of steel sailboats

Quote:
Originally Posted by mitiempo View Post
A few pages back Brent stated that the Van De Stadt 34 was an origami boat. Not really. But it is a fast way to build an aluminum or steel boat. It requires plates cut to millimeter accuracy from computer files. Here is a link to this method.
Van de Stadt Design - Info
In the ends, beyond the external frame work , what defines the shape ? The plate edges; origami principles. Van De Stadt was one of very few designers to take full advantage of the properties of steel, and not stick to wooden boat building methods for steel boats .
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Re: Pros and cons of steel sailboats

Bob
How's your new dinghy coming? When can we see the pattern layout?
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  #2577  
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Re: Pros and cons of steel sailboats

Quote:
Originally Posted by Stumble View Post
Why would anyone with a brain try to navigate Seymore Narrows in the middle of a tide?

That makes as much sense as building a boat without framing.
Someone asked how a boat can do so far over hull speed so I answered him. That is how the 40 footer went so fast thru boat passage. No one with a brain would do Seymore in a full flood. I only went thru there once in over 40 years of cruising the BC coast( without an engine, in a strong westerly at slack water)
Okisollo makes far more sense, far less dangerous and a fraction the traffic , no big ships. Lots of places to stop and wait for the next slack tide. I have run Surge narrows many times on a 9 knot tide, no problem. Start in the middle and you stay in the middle. By the time you hit the whirlpools you are in deep water, not much chance of hitting anything .

Van de Stadt , myself, Roberts, Dix , Shannon ,etc have designed many boats without transverse frames, all of them successful. You say we are all doing it all wrong? How many successful steel boats of your design are out here? More than the total of the above mentioned designers?
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Re: Pros and cons of steel sailboats

Brent:
Rowboat is sidelined while I work on two newer projects. I have plenty of time to do the rowboat and I like to take care of my clients before I take care of me. I like my work.

When the time comes I don't think I'll publish the final pattern layout. I'll publish pics of the finished boat instead.
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  #2579  
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Re: Pros and cons of steel sailboats

Well this is important because you may dupe someone into building something dangerous.

Quote:
Originally Posted by Brent Swain View Post
I had drawn the tank and specified the angle iron webs in that design by that time in the plans I sold them, which they ignored. .
But thatís not the only boat it happened to is it ! It was an illustration of your approach to designing by mistakes. Iím just illustrating that your intuition was incorrect. You initially thought it would be strong enough because of the curvature, although any designer worth his salt could have foreseen the weakness and the consequent buckling of the supporting plate. Something you didnít grasp until it happened. I think itís a good example of where some sensible engineering would have helped you from the start.

So you modified the plans after it had happened to other boats.
Now you are pretending it only happened to one boat in extreme circumstances after you altered the plans and wrote this .

"Given the tendency for the trailing edges of the twin keels to be driven up into the boat when they collide with a rock, and the fact that they are far enough back to be under the pilothouse floor in the 36, putting a 3/16th plate web across them would reinforce them without being in the way of anything. The top of this web could be T'd with a piece of Ĺ inch by 4 inch flatbar, making it extremely strong."

Quote:
Originally Posted by Brent Swain View Post
The tops of the low aspect ratio keels on my 36 are 8 ft long. I have since seen them on that site , swooning over twin keelers which have about a foot of attachement to the hull, with a far higher aspect ratio.
How do you get a foot of attachement to a plastic hull ,with a far higher aspect ratio keel, to be stronger than 8 ft of attachement to a steel hull with a far lower aspect ratio keel?
You dont!( Mike the "Engineer?")
No Mike, with a track record like that ,I wouldn't want you "Engineering" any of my boats, any more that I would let a civil "engineer " do laser surgery on my eyes.
What exactly does this have to do with your earlier designs rotating their keels up into the boat ?

Quote:
Originally Posted by Brent Swain View Post

A friend posted several pictures of a couple of very successful origami 55 footers in aluminium on that site. One I last saw at Christmas Island after which he sailed back to BC in November. Jean Marc, the owner, has cruised enough miles in the Hecate straight area, year round to have done a circumnavigation, wiht zero structural problems .He loves sailing in full storms. Harvey , on the other origami 55 footer, cruises the west coast of Vancouver Island year round .
Completely demolishes your theory about them not being strong enough.
But you had nothing to do with these designs, and you canít say what framing was used, you are just borrowing them because they started life as origami, not frameless. They have exactly nothing to do with scaling your frameless designs.

Quote:
Originally Posted by Brent Swain View Post
Here are some quotes from a letter Steve on Silas Crosby sent me from the Straits of Magellan
"I thought you should know that Silas Crosby is amoung the smaller boats sailing around , but it seems to cause us less worry that most boats down here .
The ability to get in very shallow and even dry out , or just touch at low tide, is a quality that most people, even here , do not have a clue about.
While avoiding ice chunks near the Pia Glacier, I hit a rock dead on at 3 knots . A shrug and carried on. Thanks for your helping me get here . Good boat, good design."
This completely demolishes Mikes theory about my boats not being strong enough.
No you are being deceptive again I'm not saying your boats under 36í are not strong enough. I said a scaled up design sans frames wouldnít be strong enough.

I have shown that pre welding the longitudinals flat and then pulling them into a curve along with the plating is weaker than post welding after foldup and I showed you why. So your method is weaker than you could achieve with the same material, its why your designs will dent easily.

If you pre stress something its already under load, when you push in the middle of that member it deforms more easily and again I showed you and explained why. You had no comprehension about stress reversal nor about buckling. You still donít. The internal longs cannot stay in compression under load, if you push on the hull they can only work to resist the load by going into tension because they are not in enough of a curve to be self supporting like the arch. So by pre bending them along with the plate you make them weaker, they want to straighten which assists the load in deflecting the side of the hull rather than resisting it.

That the longitudinals are arches always in compression is the whole basis of your strength argument which is simply wrong.

This in important because itís easy to show that you cannot scale your boats to 60 feet as you claim. Simply because your structural arguments are completely flawed and based on intuition. I offered to model a hull and give the imploding depth in a bow dive, you didnít want to know.

Any frameless design scaled much over 36 feet will start to get quite weak without some transverse framing. Iím still happy to model it if it saves someones bacon.

So save your 3 knot collisions in sub 36í frameless origami boats, that's where it works, I don't have a problem with that. Even if you design weak boats for the material used they may well be strong enough becaue the material is so tough anyway.

Anyone who understands structures can explain to you why shell buckling renders thin shell monocoque unsafe if itís simply scaled . You can ask any naval arch mechanical or marine engineer. Youíll get the same information. Try it we are all approachable.

Quote:
Originally Posted by Brent Swain View Post
So who would you believe, someone who has sailed one of my boats from BC around Cape Horn, then home again via the western Aleutians , or some one who has never sailed on one , an armchair expert?........
Again what does this have to do with scaling your design or your misunderstanding of how structures work exactly ?
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  #2580  
Old 12-02-2013
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Re: Pros and cons of steel sailboats

Quote:
Originally Posted by Brent Swain View Post
.........
Van de Stadt , myself, Roberts, Dix , Shannon ,etc have designed many boats without transverse frames, all of them successful. You say we are all doing it all wrong? ............
Again this is misinformation. It's your mistakes that are pertinent not other peoples successes.

Just because someone else designs a frameless boat with carefully placed inbuilt tanks acting as stiffeners or bulkheads acting as transverses and chines acting as longitudinals doesn't vindicate your design paradigms at all.
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