Welding a steel hull

Brent
The Issue is Fatigue, obserbations of one or two cycles of post yield stress are not very illustrative. Fatigue is poorly understood and is responsible for a huge amount of equipment and structural failure.

I see AdHoc is trying to teach you some structural mechanics !
I went to some effort before in another thread to show you that your arch analogy was wrong and that all the material is not in compression and that you don't understand fixity and contraflexure. You also forget shear stress in these arguments.

As for your guru perhaps you were horribly misled as to his qualifications and his supposed model tank testing at Delft ? Something sounds at odds there and you collect tall tales and have twisted the truth before now.

Yes and always the inevitable putdown for "those who refuse to think outside the box...." Then pull the magic rabbit out of the hat by the ears labelled Brent Swain origami hull. As a marketing campaign

 

As a greenhorn in boatbuilding when I started off in the early 80', I watched my "mentor", the late Ronnie Nel from Nelco Marine at the time, drawing the lines of a catamaran and asked him how does he know she will float on the drawn waterline? His answer was simple "as long as it looks right, it will be right". He was a simple and self taught man and by everything that's holy, the finished boat floated on its intended waterline - and all the others he designed and built.
Best of all, no software was used, he only estimated displacement as he had never learned about using Simpson's multipliers.....

What has this to do with this welding thread? Actually, old late Ronnie reminded me very much about Brent Swain. They both see things in a simple and layman's logic that is actually a good thing. Mathematics, technical and scientific stuff are not for them. For them things either work or do not work and there has to be a simple explanation for everything. Their experience and views are based on what they had learned the hard way in life and that is also a good thing. And this brings me to something old Ronnie also taught me, "to every difficult problem there must be a simple solution or explanation". And it along these words of wisdom I wander. Another of his great sayings was "any fool can be complicated, but it takes genius to be simple".....

It is all so easy to try to impress another with "superior" knowledge or know how about something that one forget about the genius part of simplicity. NO I do not say engineers and qualified so and so are fools, in fact, I admire your knowledge and wisdom on your subjects but there is a place and time for everything. We are discussing the welding of small boat especially aimed at the amateur, and all the blah blah on this and that is missing the point. OK, it is informative, but most DIY builders are going to weld with a domestic buzz box.
The arc strike issue on mild steel used for small boats are laughable - I agree it is not good procedure to draw a rod on the parent material to fire up your stick - rather use a piece of scrap plate at hand for that - but in my 33 years as a qualified boilermaker, I still have to see a plate fail on an arc strike. Just draw an electrode over a plate and place the inside palm of your hand on that strike immediately after the arc and I guarantee you it will be cool to the touch. How can that cool arc changes the plate with such speed as it barely penetrated the mill scale on the plate! Please, no formulas and ***** please.
This is where simplicity, commonsense come in. If one weld plate, surely the steel must be altered too if a fast cold to the touch arc strike can do that instantly? What about a little heat here and there with the cutting torch - all this will do damage will it not. What about a hole drilled and the heat generated by that...
As Brent pointed out with his experience on press brakes bending plates, I still has to see mild steel fail due to an arc strike. Small steel boats are in general much stronger than large ones and my view is that it can be build much lighter.

Fact, in the early 90's a very well known steel boat designer discussed an idea he had by building a steel boat made from interlocking sheet metal panels (18#) and gluing the joints together with SikaFlex. He told me his calculations showed it possible and this boat would have been light and used for racing....Still has a copy of the fax where he proposed the idea before discussing it face to face.
What are the chances of a stray arch strike breaking a boat whereas a top steel boat designer wanting to glue plates together:?:

R Watson has been asking a couple of times for one example of a boat that had been lost due to strike arcs and there were no takers...

Perhaps there comes a time when we have to take our thinking caps off and look at things realistically like Brent, like him or not. I know Im gonna get axed for this and for once Im with Brent on this take.

If I may fade away again with this (borrowed from a lady using it as an signature) aimed directly at Brent.

"They all laughed at him because he was different, he laughed at them because they were all the same"

 

about arch's, isnt it the nature of an arch to be in compression?

think of a cylinder being a 360 deg arch

 

Wynand
that was "well roared Lion" especially keeping in mind that you defend a guy usually not in consensus with you! (well, with nobody actually)......Chapeaux!


Wardd
do you know the topic of the thread???

 

my post was to one a couple posts ago, which involved longs

 

Ahh, thank you........

 

And you never will see that on the press which is why it's a misleading observation to begin with.

But take an engine mount overly built and watch a crack propogate across a flange down through the web and into the girder all from one weld undercut and then you start to get a feel for fatigue. Yet so many times in low stress high cycle areas you ask for something to be re-welded and the welders think you are being a know all becasue they Know it's OK !

So where do you draw the line between a feeling that may or may not be accurate and a scientific approach that may be over the top? Any NA/ME is trained for best practice for relatively highly stressed ship building and they will tend to apply some excessive caution when applied to boat building. That's where Ad Hoc is coming from.

However I agree as I said before that the hull plate on a smaller vessel is going to be immune, even incredibly sloppy repair inserts with square corners hang in there year after year even in steel fishing boats yet in a ship such practices would lead to a quick failure.

 

A curve is not necessarily an arch.

 

The boat was a Pipe Dream sloop feastured in the book Skenes elements of Yacht design. Buy a copy and look it up. It was tested at the Davidson lab in New York where many of the Americas cup boats were tested.
She had zero directional stability and was hopeless downwind . Regardless of what your calculations may say, the expereince of trying to get her to sail a relatively straight line to NZ was a battle , completely overuling your calculations and theories.
Definition:"Elephant" A mouse designed by a committee.
Thanks Wynand
Brent

 

Brent
That's a typical misunderstanding

Any sailboat designer looking at these lines will tell you that you could have expected such an experience and that this is a half way ******* form that was quickly abandoned.

All totally predictable today with those calculations and theories you are so afraid of

Also note that the tank testing was for wave making resistance not for directional control .

 

Wynand,
If these - see below - are the type of boatbuilding ideals that you believe we should accept and that you believe will assist the amateur builder in producing a quality steel boat, then I believe that I will keep my thinking cap on, as these ideals are ***** to me.

Brent Swain quotes:

1) If the metal is sticking out beyond the flux, it will stick , Drag it across the steel until the metal is well back from the end of the flux. Drag it a few times until you hear the hollow sound, then drag it up to your weld and continue welding.

2) That is why a while ago 6011 was the only rod that Lloyds would approve of for small craft.

3) A good cut needs no grinding, unless you are trying to maximise the number of hours you are being paid for. Shipyard workers do that a lot.

4) Small steel boats are so grossly overbuilt , that any discussions of welding rod choices is a purely acedemic debate, with nothing to do with the extremely remote liklihood of welds ever failing.

5) When I jack the stern up to put the skeg on , the foreward centreline is horizontal , a good time to 7024 weld it, before jacking the bow up to put the keel on.

6) AC with 6011 is far better than DC for fitting , as it is far less prone to sticking when you are in an awkward position.

7) Welders working on one of my boats said" Brent is a good fitter, but the only problem we have is he doesn't grind all the edges." I said" Do you know what they call a fitter who grinds everything? A slow fitter."

 

Welder, first of all, it is dangerous to assume things and make the deductions claiming that I stand for Brent Swains ideals and believes. Im not going into a farting competition with you or anyone else, but I would suggest you read my post again and also between the lines. Im one that had taken on Brent many times in the past and Im on record about my view on Origami methods and the now famous "hillbilly" remark was made by me.

That said, my CV on steel boatbuilding include 19 boats - 65, 57, 45, 43, 40, 34, 24 ft size range. I had paid my dues and think that I can make a fair comment on steel boat building and have the qualification a fully qualified boilermaker to back that. As I had done my apprenticeship at Sasol - a refinery, it is normal procedure there for boilermakers to qualify as coded welders in all mediums such as Tig, arc and gas and also pass a NDT and destructive testing before starting your hands on training in the shop/plant.
Since Im not shy to name my experience on steel boats (not ships) what are yours?

If Im an *** hole, I can also start rambling about steel compositions, different coefficient of expansions etc etc to impress the uninformed. What would it bring me in the end instead of keeping this simple to inform the uninformed. Seems to me every time someone question something you preach, you are on an attack. Grow up man, criticism can be either destructive or constructive, all depends on how you want it to be.

If you care to read my post with an open mind, you would have noticed that I am with Brent on this silly arc strike issue on steel boats, and although I don't condone that practice (read post) it is only only a hypothetical issue. Rwatson challenged everyone for one example of just such a failure of a boat with no takers yet.

And since you have raised a few point of Brent's previous remark which you assumed I underwrite, I will remark on that.

1. how would you go about with an electrode that had it flux damaged at the tip - cut it off with a side cutter or what? What he said is true, just do it on a scrap piece of plate at hand and then go back to the weld.

2. Since one works with mild steel, why not weld with mild steel? In my country we use E6013. I personally weld with MIG using ER70S-6 wire.
About his claim to classification is his view and not mine.

3. If you are a good artisan, you can cut that plate clean. In fact, I hate grinders around me and all my cuts, any thickness of plate, are super smooth with "thin skin" peeling of the cut faces (just like a straight line cutter) without any slag to remove.
I hear you, yes, if you want a butt joint that has to be x rayed, one does not want impurities in the weld and the edges get grind bevel and shiny with appropriate landing thickness and gap. But we talk small boat build of mild steel and weld with a buzz box using mild steel plate.

4. Refer to point 2.

5. If I read this point correctly, he tries to get his boat level to pack in a fillet weld with E7024. It is a good rod for that purpose on goes a long way fast. How he get his boat level, is his affair and building in the open a crane is not a common sight. At least he has a plan getting the results and that is simplicity. I do not condone his method, but admire someone trying to solve a problem with little or nothing at hand.

6. That is his view. I also prefer an AC welder to a DC welder, especially welding over some slight gaps. It is a personal preference and don't be so upset if others don't follow your gospel.

7. Refer to point 3. I never ever condoned sloppy workmanship.

 

I'd suggest that you are the one getting wound up, Wynand, not me. Personal issues with Brent aside, the purpose of this thread was to suggest sound practices in boatbuilding to amateur builders. Certainly I admit to becoming tired of Brent's attacks, not only toward myself but toward various designers, boatbuilders & members of these forums. Is it so difficult for you to understand that I couldn't care less about the level of problems one could, or would not, experience by following Brent's sage advice? You started this friggin' thread and then, rather than leaving the comment that you'd use a piece of scrap to burn off the flux, you continue the deflection of the issue to continue the silly argument that it(arc strikes) will or will not compromise the plate. Any first-timer reading this thread will be at a total loss as to what advice to follow. That is the real shame.

Sorry if my response to your post pushed your ego out of shape, Wynand, but dragging a rod across plate is as poor a practice as the others mentioned. I think your reading more into my post than is there. As for the personal remarks, stuff them & relax, I've too thick a skin to be bothered with that sort of noise.

 

Welder, it's not about egos my friend, but wrong assumptions made by you about me.
I do not have to proof what I say I am and my remarks are based on my experience gained building quite a number of boats in steel and as an boilermaker period.

Although I do not support Brent's views in any way, I do respect his tenacity for what he believe is right and experienced over the years. Perhaps he is rough and not so precise, so what. Just as you like to dish out your views, so has he, and others the right to do so. Maybe he believe he is right, maybe others think they are right and so on. If you had read my the first two paragraphs of my posting near top of the page, you may perhaps understand what Im trying to say...

There are some prolific posters here such as MikeJohns and AdHoc to name but two, whose expertize I admire that try to help and explain things to Brent and others and myself, but when you are like old Ronnie I described, it would not help because he is not a figures man and goes by things he had done, experienced and trusted. And that as said before, is not a bad thing at all. I for one would hate to be a hypocrite to judge anyone for that.

I did not started the silly arc strike issue that really has no influence on a small steel hull boat as had been nicely put by MikeJohns post #254. And the irony of all this in your own words "Any first-timer reading this thread will be at a total loss as to what advice to follow. That is the real shame."
This thread was started to inform the first timer or amateur on how to weld a boat - not pressure vessels or hi tech stuff. Why not get to the genius of things by keeping it simple and informative and applicable to small steel boats.

And lastly, I do not care if dragging a rod over a plate is bad practice or not, it had worked for me the last 33 odd years, so why change? The right way is not necessary the best way and everyone to its own.
I've said my piece on this and will fade back in obscurity for the time being.

Thanks to:
1. Apex, you are indeed a gentleman
2. Rwatson, nice questions but I do not think you will get any takers to produce a hull lost to the issue in discussion recently.
3. Brent, you're welcome, but don't sell me on Origami please
4. MikeJohns, your good engineers advice and professionalism always admired by myself and many others
5. AdHoc, same as Mike and I wish I can know your true identity

 

Welder/Wynand

I hesitate to get in between the two of you but perhaps I may “arbitrate” a tad?

I can read between the lines as much as anyone, certainly on both your threads. To me Wnyard is not a supporter of the practices used by Brent but clearly feels that being a “time served” and “…but admire someone trying to solve a problem with little or nothing at hand…” , is due some respect; this also falls in to my enormous respect and admiration I also have for the majority of welders/fabricators I know and those that I do not. However, I am on the design side of the argument as such. I can weld, very poorly, since it is not my daily job. I took it upon myself to spend approximately 30~50% of my working week on the shopfloor after gradutaion. If I do not know how my designs are going to be built, if I do not know how the fabrication process, in real practice, affects the final design, how can I design correctly? In my basic “apprentiship” I did under their tutelage, having to don the heavy leather gear and the hard poorly fitting helmet and loosing almost all my manual dexterity by wearing such thick gloves, breathing in shitty fumes, getting blow-backs that put the shits up me, one is instantly left with nothing but enormous respect. Such difficult hard working conditions, yet many I came to know and have become best friends, enjoy immensely their work and have such pride in their work. Something that is difficult they take as a challenge.

Several welders/fabricators I have worked with over the years have shown me the right way and the wrong way. I have reciprocated to them “technically” what is the right way and the wrong way (we even did simple workshops for education to the draughtsmen and the welders)…and then a compare and see….doesn’t take to be Einstein to realise that the rights and wrongs were pretty much the same. However, some aspects I raised challenged their preconceived ideas. This is where I we took tests pieces to investigate the “myths” and what should or shouldn’t be done as a result. All the time the one area that covered these ‘myth’s, was QA.

As I also become more experienced and confident in debating and tackling fabrication issues, owing to the excellent grounding I was given over a period of some 5~10years being on the shopfloor daily, I was often sent around the world (to survey damage) and also to the various yards building our boats under licence. What really got me started in much more depth than noted above was when the design was blamed for warranty issues or costing production too much money.

It basically came down to very simple reasons. Of the cracking and other issues, some 90~95% of the cracks were owing to fabrication. This came as something of a shock to the production manger. However, having identified the source, it became clear that a small percentage of the production guys either were too sloppy/lazy or just didn’t care about quality. They felt it isn’t necessary, how can a slight over grind cause a problem, or “I’ve put down plenty of weld, that aint gonna break” type. Over the years I have backed this up by doing my own personal research into fatigue of welding and fabrication in aluminium structures. During this whole process I started my Masters and PhD to obtain more resources to understand much better the “mechanics” of what is really going on, to separate those old wives tails of “it’ll be alright”. It has also spawned many technical papers I have had published, even to the point of the International Ship and Offshore Congress (ISSC) have recognised my work. (Slight digression, sorry I’m not here to blow my own trumpet, just to give you a bit of background where I am coming from).

The point I am making is best summarised by a simple event that occurred many times during my “education” process of fabricators.

In my last yard where I was the senior naval architect, I was asked by the production manager to design him a simple ramp, so he could drive his small digger up onto his pick-up, so he could transport it around much easier. I did the calculations and gave him the simple design. The production foreman, who was in charge, looked at it and said this is crap, over built, don’t need any of this *****. (I wasn’t aware of this at the time). He was a person I never got on with at all. Because I constantly questioned his methods, he didn’t like a young whipper snapper in a suit from the office telling him, who has spent 40 years building and welding boats what to do, he knew better. As such he decided to throw away my dwgs and he did his own, because he knew better.

The ramp was built, and when the Production manger used it for the first time, the ramp collapsed and broke with the digger only half way up. Total waste of time and money.

Here, is also another perfect example of this mentality, given by one who also just doesn’t understand and feels his “time served” is enough of a qualification the be listened to and not to be questioned and “I know what I am doing”:
http://www.boatdesign.net/forums/metal-boat-building/metal-frame-detail-28371.html

It is people like this old production foreman, and the poster in the link above, that create the environment of “its ok ive done this before, don’t worry about it” and have zero interest and respect for the nature of quality in all its forms. They also give small boat building a bad reputation. These people are not sent over seas to investigate why cracking has occurred nor do they have to write the reports and the recommendations, nor are they the ones who have to pay the increase in insurance during warranty of the vessel, nor do they have to justify to the company in spending more money in production to prevent it occurring again. Since as the designer I must ensure this doesn’t occur again, but, to do so I must know why it happened in the first place. Just rewelding, as is done by many, is not the solution. They simply don’t care, they have done their 9-5 job and go home. These are fortunately, the minority, but they shout the loudest. An empty can makes a lot of noise!

It all comes down to quality, following procedures and enforcing them day in day out, whether, now going back to my point, the welder is doing a good job with the meagre tools and resources at his/her disposal or not. So whilst I hear and understand Wyanrds point, respect must be given for those that ‘get the job done’ anyway any how. In design, this is often what we are faced with daily too.

But and this is the crux of all this thread, I finally sit on the same side as Welder. Since whether one is doing a simple tab connection to lift another bit of structure or bridging two plates for butt welding or a simple tack weld or a waterjet structure or engine girders, the same method and procedures must be followed, no exceptions. If you do not follow the taught and required procedures then the boat/structure is just waiting to fail at sometime in its life, not a question “if” but “when”. When depends upon how much the boat is used and how poor the detailing is. (I've seen as little as 3weeks into new service, a structural memeber fail, owing to sloppy workmanship and not following proper QA).

There cannot be any excuses for poor quality, regardless whether one is building a bird table for the garden, a boat for a mate or a boat built to Class for a megayacht or super tanker. Where is the pride and professionalism???

It cost nothing to smile, but a smile takes more effort than a frawn (smiling takes approx 40 facial muscles), but the difference, affects poeple behaviour most markedly and is very obvious...it also cost nothing to follow correct procedures…just a bit more time and of course the effort to begin with.

Well, that is my two cents worth.

Thanks for the kind words Wynard....still feel the same now after my 2c worth??