Any one used metal frames inside of glass boats !!

wynand,

I think your aggression is misplaced. while it is true that when there are spectacular failures it is always engineers that are blamed, but the real news is that such failures are so rare they are actually news worthy. AS Par pointed out, the vast majority of structures and mechanisms of man made objects, from cars and aircraft, to bridges and buildings, are so safe most of the billions of people that use them everyday never even think twice about it. That is an incredible testament to how well the design process actually works.

Failures of any man made object, is always due to human error in one type of another. I have seen many more failures due to tradesmen or installers that failed to follow the specifications, either out of carelessness or because of ego (they thought they knew more than the engineer) than from bad engineering. But both type of failures do occur. Engineers can make errors as much as mechanics, welders, pilots, doctors and everyone else. Of course when an engineer makes a mistake, hundreds if not thousands of people can die. It is important that engineers work together with the tradesmen, as well as other engineers, to try and anticipate every problem that can occur (not an easy task). And it is always critically important you choose the correct engineer (or team of engineers) for the job at hand. Yes, there is nothing like experience.

OTOH I have always thought it odd that many engineers have little or no hands-on experience. It was the intellectual challenge that drew them to the career, yet it seems to me (being an engineer), that engineers are the design professionals between the physicists and scientists, and the craftsman or tradesman that actually build the item. That means the engineer must understand both the details and practical aspects of the tradesman's work, and understand the scientist equally well to do his job. You can best learn that by participating in it.

And much of engineering is more practical experience than application of physics. Much of ship design, as well as buildings, bridges, etc. are applying historical experience and formulating a design precess for phenomenon that do not lend themselves to scientific analysis. It is not precisely understood how buildings, especially large ones, interact with the soil during earthquakes for example. But experience has taught us if we do certain things to design the buildings, they hold up pretty well. At least for traditional construction methods. It is always the "new" high tech construction methods that get analyzed based on imperfect and little understood phenomenon, and cause spectacular failures after the big event. You can not put a skyscraper in a lab and test it with an earthquake, it is only after the event that you know if your design assumptions were valid (and large earthquakes ALWAYS results in building code changes-indicating that we are really "there" yet). This btw is why the climate change predictions are so suspect to those actually educated in science, and the history of science.

So we have design processes that work pretty good, not perfect, but good enough to get to the moon and back, supply food, fuel, transportation, safe housing and health care that keeps the majority of the population, in the more prosperous countries, safe and alive.

When you need an engineer, you must carefully select for the one with the skills and experience matched to the job you want done. Just like a medical specialist, lawyer, or anything else, the responsibility is on the one who does the hiring to make the correct choice.

 

What aggression I only lost my patience once after trying to be polite and patient for quite a considerable period and the receiving end was Brent Swain... Need I say more....

Petros, an excellent post. Thanks

 

How about steel frames in wooden tall ships over a hundred years ago? They were viable in working conditions.

Dino

 

New materials and differant construction and closer tolerances but i do understand what you are saying . The exspansion thing i have worked out a very simple way to compensate for movement yet still have a pretty ridged kind a boat !! Will wait a little longer and see what else come to light in thei post !!! Its interesting and good to hear differant peoples exsperiances and the knowledge they have buried away in the grey cells of age !!
I have no intention of watching the sun come up , go across the sky and go down and do nothing in between times !! .

 

How about steel frames in wooden tall ships over a hundred years ago? They were viable in hard working conditions.

Dino

 

I'm reminded of the lowly 'ol steak knife. Evey one's silverware drawer has them, plastic handles, formed around a stainless shank. They've been around for many decades and countless millions of dishwasher cycles, which I suspect is much worse, then anything mother nature can toss at a boat. Yet they seem to stay together, dissimilar material expansion rates and all. Must be a fluke of engineering luck.

Steel frames in ships and yachts, have long been a source of maintenance difficulties. We have better "isolation" techniques now, but the old ones really didn't fair well in durability.

 

Horses for courses, shipbuilders and boatbuilders have been experimenting for years and this is how progress is made, by someone doing it and finding out all the rights and wrongs but then not being a smart A*** about it but passing on that knowledge so that others can learn.
Good thread and some interesting comments.

 

wow i cant believe this debate is still going on !! Keep up the good work !!

On a personal not i am all for using the same materials for everything . If you start with fibreglass then you use fibreglass for everything . If you start with wood you carry of with wood same with metals what you start with you carry on with . . No mater what size or shape you are making .
Just to get off subject . I spent time walking looking and working in Japan , the old buildings were build wholely from The local timbers only !! The trees were marked and the timber from the north side if the tree was used in the north side of a building ,the south on the south side of the building and so on , These beautiful 500 and 600 year old buildings and some even older look as good to day as they possibly did not long after they were first built . Have no metal fastenings any where its all done with fancy joins dowels , pegs and wedges and interlocking shapes and joints and differant timber that have special properties .
Back new Zealand when i got home I build a really big deck round my house more that 10 years ago using just some of there technology and fancy joints and vertually no fastenings at all .To this day its still 100% stable and dosent move ,made no noise!! (creeking and groaning etc ) non of the joins changed or moved with the seasons !!. The inspector came to do his thing when i listed the house to be sold to check and couldnt find a thing wrong with it !!
Once its understood how the joints work and what they do its reall quite simple . I just made jigs and used my router to do 99% 0f the joints and finishe off with a sharp chisel .
Lived and worked in Korea and they to have there own ways of building traditional old buldings .Lived and worked in Japan and traveled the length of the country and saw there beautiful old buildings !!. Am now in China and its quite hard to find old wooden buildings and have to get into the countryside and off the beaten tracks , Its interesting to see the same principles used in each country but with slight variations according the differant timbers and materials that are used .
Sorry !! carry on !,just pretend i wasent here !!

 

The reason we now use man made materials, instead of holding a buffalo hide up to catch the wind, as we ride a log down stream, is because we can do it, faster, lighter, cheaper, stronger and more reliably.

It's absurd to consider just wood on a wooden boat or just 'glass on a 'glass boat. A wooden boat is a far better boat is you use a "wood product" such as plywood for the deck (as an example). It's man made and the best deck you can put on a wooden boat. No one that designs, or repairs will argue this, unless you need the vessel to remain pure to it's roots, which would bar the plywood subdeck.

It's just as ridiculousness to not employ a core in a 'glass boat, or maybe some metals or possably other non-'glass materials, to get lighter, stronger, more reliable structures.

Tunnels, you sound like those that suggested an airplane wasn't an airplane unless it had a wooden frame and was covered in doped cloth. In fact, the engineers had quite a time, designing the first metal planes that were as light as wood, but this soon passed and now a cloth covered wood framed aircraft is a relic, much like those that can't accept the realities of existence.

As in the animal world, the human world is governed by the same, intrinsically simple rule, that can't be breached if you expect to survive. The rule is "the most essential element of all existence is change". Without it, the dinosaurs would still be here and we; scared little rodent like beasts, hiding in the rocks, still awaiting our turn and the "big wheel of life".

Sure we can admire and enjoy techniques and methods of old, even continue to employ them, for the quaint of heart, but frankly compared to modern techniques, those cute, clever and masterful craftsman like bits suck. I've built many things in my life, old school and new. I do have a fondness for some of the old school stuff, truly enjoying the work, but again, in these times why bother. Why bother when you can do it in a fraction of time, with higher precision, stronger and lighter materials and well seasoned engineering. Sure trunnels are lovely, but the hell with that, when I can pull out a drill and a box of screws. I'll be done, relaxing with a beer, while I watch you still laboring for weeks with your damn trunnels.

Welcome to the age of the mammals Tunnels . . . please catch up before something runs you down for dinner.

 

Actually Par, an optimized wood truss and fabric wing is one of the lightest lb/sf aircraft structures ever designed, beats out just about everything else except for very costly and specially made exotic composites. Wood wings have twice the stiffness to weight ratio as fiberglass and epoxy wings. Do do not call them obsolete just yet.

Wood is too labor intensive for production and only suitable for low speed aircraft (well the first German jets had wood spars and plywood skins...), so it is not really viable in a production environment for transonic or supersonic aircraft. Biggest problem is getting large quantities of high quality wood, and also enough skilled craftsman to build them, plus down stream maintenace and inspection is problematic as well. But for homebuilt projects, still a viable choice.

 

I still work and play with dinosours every day !! dont you ?? They have a fancy name these days called bosses of even managment is the modern terminology !!
Animals still have and use there instinks they were born with but some where in ths course of evolution man has lost just about all of his natural instinks and spends his days walking in circles and mumbling like he is looking for something small that he dropped in the dirt .

Anyway getting back to Boats ,wood and plywood takes a lot of beating to build light and strong structures like planes and boats . Glass is pretty cool as well but its the way we use the materials we have on hand thats the secret to its lasting success or its quick failure !

 

Okay, you lick your butt, while the rest of use use toilet paper.