Cocoon

This is my first post and I have absolutely zero experience in boat construction. I do however have tons of experience in perfectly (un)reasonable deviations from the trodden path.

I was wondering if anybody here has considered/experience/tried using e.g. a woven wire mesh and/or inflated balloon and a pultrusion method to create composite components that would fit together like large soap bubbles. For example, it should be straightforward to create a double hull with a honeycomb web using fiberglass wound around hexagonal foam prisms.

Theoretical advantages are that material cost is much lower as fiber content can be very high and local density is controllable with simple protrusions on the mold. Additionally, fiber on spools is considerably less expensive than any type of fabric.


P.S. Question inspired by a post on the FB page of American MENSA

 

You could build with foam core construction as has been done by members of this forum.

 

http://www.boatdesign.net/forums/fi...ilding/hand-lay-up-coracell-m-foam-42690.html

 

Or one could try something new. That's why I asked if anybody here has tried/considered a method that resembles an insect spinning a cocoon. Where is the point in making the same mistakes someone else has made, if you can make new mistakes Or maybe even make an exiting discovery.

It should be much easier to simply foam up the cavity between two layers of fiberglass than to shape the foam beforehand.

 

Good luck with it. Keep us informed of your progress and welcome to the forum.

 

Yes, masts and other shapes that are symmetrical around an axis are routinely made like that.

 

I don't see why the method could not be used for asymmetrical shapes, as long a the shape is locally convex about the axis of revolution.

 

Asymmetric shapes around an axis, would place differing loads about the center of gyration, thereby forcing non-uniform distribution in the column or beam. The resulting load paths would be have obvious results.

Inventing new ways of doing things, assumes you have a grasp on the physics and other disciplines necessary, to make a reasonable hypothesis, in which to extrapolate on. Taking a good swing or guess isn't the wisest avenue of pursuit, in spite of what mother nature might randomly consider successful.

Fiber orientation, particularly in a "cocoon" like arrangement isn't new. Many fabrics and other man made materials reply specifically, on this structural approach. It's not especially logical, but to a degree can be a success, if heavy and unpredictable. If you can arrange the random fiber orbits into paths, that more closely follow load paths, then the structure is lighter and stronger for the same amount of material, which usually is more desirable.

 

Having a grasp on the physics and other disciplines is good at eliminating the things that can't work, but not very unsuitable to determine whether something is really practical. Like most things, thinking suffers from diminishing returns, so eventually you go 'what the hell, let's just try it!'

Two billion years of evolutionary optimization leads to very efficient solutions especially when it comes to materials and structures, so success is definitely not random. On the other hand, no animal uses wheels for locomotion, which illustrates that nature's way is not the only way to do thing well.

 

I found this example of wheels in nature on yahooanswers.com: http://www.bms.ed.ac.uk/research/others/smaciver/Cell biol.topics/Cell_Locomotion.htm

"Bacteria invented the wheel!"

 

Son-of-a-gun!

 

This is fundamentally flawed and certainly not defensible logically. If this was the case we'd have de-evolved and would now be back to drawing on cave walls, from lack of return on our mind use. Thinking is the only way to explore anything new. Disciplined thinking is the fastest way, though some have gotten lucky with the crap shoot approach, it's historically, not the most productive method for results, unless you have slaves and/or minions to get some test results on first.

You've answered your own question and evolution or mother nature's techniques, have repeatedly proven many more bad ideas than good. Both also take way too long for most folks to appreciate, so we're left to the thinking thing again, to not only improve what takes natural selection millions of years to sort out, but to do so with a level of conscience that is more palatable to folks venturing into unnatural environments, such as riding an elevator to the 50th floor, flying at 35,000 feet or sailing farther from shore than you can swim back to. These are all instantly deadly environments, if your guess work doesn't pan out. Hence the reasonable instance for some forethought and understanding of the concepts, principles, dynamics and physics of it all first. Let mother nature screw around with the crap shoot technique. We can use another ostrich or two.

 

I have a degree in economics. When economists say "Diminishing Returns" they really mean "Diminishing *Marginal* Returns". I hope that clarifies things.

Although in context it is rather obvious that this was meant.

You've probably heard of the saying "The proof is in the pudding". You can think as much as you want to, however at some point you have to conduct an experiment that could prove that you are wrong.

I want to know if anybody here has tried the above method to build the main composite components of a boat.

PAR, I really appreciate your input, but you as you evidently have not tried it, you clearly lack the necessary expertise to answer my question. So thank you very much, and have a nice day.

 

So, does a degree in economics qualify you know whether your original question is sound? Does it qualify you to understand composites and structural engineering..does it qualify you to know how to build a 100ft catamaran..??

So…no it seems.

Thus, it strikes me as odd, that you appear to have no experience/qualifications on the subject you wish to discuss, yet you are very quick to dismiss those whom are eminently qualified (PAR) to provide you with the answers you seek, simply because it doesn’t fall into your expectations.

No wonder the world is in an economic meltdown, since economists lack necessary expertise to understand the problem.

 

No, it explains why there was terminological misunderstanding.

Some people have degrees in one field and are employed in another. Some people even have more than one degree.

So, I do have a couple of year experience in process design, engineering and manufacturing fiberglass reinforced polyurethane automotive components. Not terribly useful, unless I wanted to crank out a 100' catamaran every 135 seconds.

I was looking for someone with experience with pultrusion processes. What I got is a trivial answer anybody could have found out using google search and a fallacious appeal to authority.