Naval architects and designers are a waste of money!

I took this picture when i was on a boat, the boat seemed out of balance to my entrained eye.

When i asked the boats captain he said they added a structure to "use the available space" and ended up moving the center of gravity too forward.
After realizing the mistake, they will remove the top structure to balance the boat again.

Not sure if this applies to this threat but i figured to added it anyways ...

 

You know... those people in the Wooden Boat thread did have a point, even though the whole thing was a disaster.

Given software and knowing how to use it properly and assuming the algorithms are correct, an experience seaman *should* be able to design a boat just fine, from a buoyancy and righting moment perspective.

Does anyone know where these people went wrong in feeding the data into the program? Did they mess up on hull plating thickness? Did they not add all that "real estate" on deck into the program?

I don't understand how, if that boat was entered into any program designed to calculate standard design values, the people could have been so far off.

Personally, I found it to be a much better use of my time to just pay Kurt Hughes for one of his well-found designs. I could have spent a year, full time boning up materials, hull shapes, etc. but Kurt's boats were just right anyway, so why bother?

Still, those people must have done something wrong with the software. Anyone know what they did?

 

This is one of the major points I think:

There are people around who believe that owning the software makes them a qualified designer.
Once in an amumesment park I saw monkeys riding a bycicle. These monkeys were smart enough not to line up at the 'tour de France'

Even if the program gives the correct values, they are useless without interpretation or if the operator has no clue what i.e. stability is. I have talked to boaters who believe that high stability means 'it will not break'.

I tend not to trust my program and whatever it tells me about parameters, I still calculate separately; just to be sure.

If we add an unstable personality with a profile neurosis and a superiority complex, it not only becomes a psychologic issue as well, but it also puts peoples lives at risk.
(Somehow many of us who 'design' have a self consideration close to 'Superman'; this includes me, and you and YOU!)

It is time now for SOLAS II: **** On Lakes And Sea, to prevent products like this.
And this:

 

Ok, mostly I hear what you're saying and agree.

However, given proper CAD/NA software, why would you go and recalculate everything the computer already did? Certainly the computer is less prone to error than a human is in calculating complex equations.

Entire Airbus/Boeing aircraft are routinely designed in software systems with no additional checking. In fact, just about everything in the modern world is done this way now.

I understand that if you think "stability" means it won't break, you're in for a world of hurt if you use software. However, if you know what the simple terms mean, input correct data and build to the specifications, you could easily come up with a workable boat. I guess, though... if you don't know where to begin and haven't had any time at sea, you could design some crazy thing with flat bottoms or something stupid like that which would cause pounding/slamming, but might seem right in the computer.

Guess you need a little "real world" in all cases.

Thanks.

 

Successful engineering design is about making early critical decisions on the basis of a few manhours, then proceeding to the next stage (some thousands of hours) where more detail is added, then to the next stage (millions of manhours if you speak of Airbus/Boeing) and then on to construction - and at each successive stage, the earlier decisions survive contact with more detail/reality. In the case of the Woodenboat thread, the boat clearly did not manage its contact with reality very well.

The millions of manhours invested in the "design" of a Boeing or Airbus are based on a basic geometry that has the volume, weight, lift and power characteristics in balance. That geometry is initially created by a few people and does not need (though is facilitated by) software tools.

An aircraft geometry that did not have these things in balance could be analysed to death and still not fly very well (e.g. the structure emerging from the FE checks might be too heavy for the wing size selected in the beginning). Then the wing might have to be made bigger - which makes it more heavy, etc etc etc.

This is the "design spiral" that you need to keep moving in a converging direction.

Same with ships. Stability is a combination of hullform effects (easily calculated by software if you input the hull shape) and weight, centre of gravity effects. Unless you model every part in the ship from the outset into your software (not viable except on small boats or naval projects) you have to ESTIMATE the out-turn weight and CoG before you go too far. That is where experience comes in.

Probably in the small boat world, the successful designers who are not also builders have collected enough data to make early estimates of weight and CoG reliably. In the big ship world, the people with the real out-turn data (handy for making the estimate for the next project) are the SHIPYARDS. This kind of information is gathered and guarded jealously.

 

... by trained engineers who know the numbers to be fed into the software, the numbers which could reasonably be expected to come out from numerical simulations, and the limits of the software itself.

And after the simulations are done and a model created, everything goes in the wind tunnel for validation and for additional testing in the operational range not reliably covered by the software.

The passenger cabin areas which require good aesthetics is done by interior designers, or at least by experienced professionals who can judge a good-looking from a plain ugly shape of stuff.

Apparently small, but fundamental details.

 

In printing with the latest color management programs, tools and equipment there is a huge difference in quality when an experienced printer is adjusting colors then letting the software do it.
Same at design stage.

To get the best result its best to integrate both experience and software technology. I do believe they both are needed for a good result and running with one with out the other is taking unnecessary risk.

 

I would agree that you have to know something about the values you are inputting and the expected output. I assumed anyone using the software programs would have studied enough to know that?

Judging by the woodenboat forum thread, maybe I have assumed wrong!

So there are people who think you can just "push a button" and have a boat ready to go? Yikes!

 

I call this category of amateur designers 'software users'. They download FreeSHIP or Maxsurf, click magic button and... get resistance and power prediction for sailing yacht by Savitsky and Holtrop methods. No sence, but looks impressive... for them.

Capabilities of 'software users' are limited by available software. Meanwhile, capabilities of professional designers/naval architects/engineers are extended by available software. This is the difference.

I spent a lot of time developing engineering software for my own needs - from hull shape design and fairing, stability calculations... to power prediction, VPPs, manueverability simulation. I am sure may collegues here have similar experience. With such knowledge any commercial software is not just a blackbox with unknown outcome, but sensitive instrument that should be tuned and properly handled.

 

I know at least one and heard of another (lucky, never met that one as well)
The first one went a step further; IMPROVED Alik's laminate layout by using more chopper gun CSM and less Woven material. In the end the hull was heavier. He also uses polystyrene as a core for POLYESTER laminated stringers...Has a pretty website, though

New theory: 70% of Earth's surface is covered with ****.
I pray that someone proves me wrong.

 

The reason maybe: I grew up in the pre-PC world and still did not find full trust in these machines. They tend to have intentions of their own

(I remember one of my own early cases where I spent almost all night to iron out a dent in a hull; until I found that I was struggling with 0,01 mm only.)

 

There is little doubt that designing boat hulls is a highly technical field. It's obvious from the curriculum a Naval Architect has to go through. It is also obvious that an untrained person in designing boats would not be qualified to design a super tanker or cruise ship. That does not mean they could not come up with a decent design for a small boat using widely available literature on small boat design. There are a number of "starter" Small Boat Design books available. If you want to design a boat, you need to at least educate yourself on the basics of boat design. If you want a 12 foot row boat, are you going to just grab a number from the sky for the BWL, Draft, etc.? To do so would be a sign of poor judgement and also a sign that the person is venturing into a project that he or she is not quite ready for. Most Hull Design Software Programs dish out a bunch of numbers, such as Block Coefficient, Prismatic Coefficient, and much more. These numbers are very easily checked against by hand calculation if you have done just a little bit of homework. Would it be fair to say that the Hull Design Software is completely useless? I don't think so. The Hull Design Software allows you to make changes to your design, and view the results of your changes very quickly. You would labor hours with pen and pencil over a drafting board or CAD Program doing the same exact task that you could do by computer IF you know what you are doing. When do you have an idea that you know what you are doing? Once you have confirmed the results by hand calculation. Confirming the results by hand calculation can usually be done fairly easily. Most of the formulas are very short and simple - can you take the square root of a number, or do a little manipulation of the formula using simple algebra? You don't have to "derive" the formulas. The formulas are there, and have been well tested. To say the computer is useless is nonsense. Ask a professional drafter. Ask him or her if they would rather use paper, pencil and eraser rather than AutoCAD. I think they would choose AutoCAD if they new what they were doing. It all comes down to your background. Do you have the background to do what you are doing? Sometimes you really do have to study and prepare for work you have not done before. This is typically a process that is ongoing; you can work a lifetime at a trade and still learn something new every day. As a final note, it is my personal opinion that you should always check the numbers that the software dishes out. This may take some time, but it is necessary to confirm the results all the time! Personally, I check the important numbers such as displacement, and other coefficients. If you ever want to be considered somewhat knowledgable in what you do, you have to have an idea of what you are doing. Blindly drawing up a Hull using Hull Design Software without knowing any more than what the "pretty images" look like is a big mistake. Not only that, you are missing out on the learning part of the process. There are alot of good books out there on Boat Design and Boat Building for amateur Designers and Builders. If you don't make use of the educational material, your never going to know what you are doing.

 

Hi Wayne,
Just to prevent misunderstanding: I also love my design program and don't want to live without.
But as the cases above seem to proof, the atomic bomb can be dangerous in the hands of an ape...

 

Just my 2cents

I read and saw all the original pics and postings a couple of times over

those 2 guys were smoking wild stuff from the first "design meeting" after a wild night out

they obviously never even bathed and played with a rubber ducky in the water - foolhardy at its worst

to say that they missinterpreted "software" is a missnomer - those guys cant read - a high school kid that has sailed a laser wiil come up with better results from ALL and ANY of the multitude of software available. I fully agree with the previous postings that a computer and software wont make a NA but those guys are an insult to modern software and programs

the term "pig headed" is probably close enough

 

So lets hear the story behind this vessel. Is there a thread link?