carbonfiber/kevlar layup

[tunnels]

Gorilla read it right..kevlar,kevlar, carbon/f, core,carbon/f,carbon/f

That was the thought of using coremat in the first place..to gain thickness..I don't care about what the strength of the core is.thats what the carbons for.

Kevlar is going down first because of the impact resistance, then the carbon for strength.

Wood.....is totaly out of the question for me anyway.

"Kevlar is going down first because of the impact resistance, then the carbon for strength."

Need to take a step backwards and sit and think about whats been written.
Impact! but from what ? impact as in hitting a rock or hitting a log ? or Water impact from waves big or small ?
Theres are two completely differnate kinds of impact resistance !!

Carbon for strength . How do you interpret the strenght of the carbon on the inside laminates what is it doing to give it strenght ??
Point remember here is carbon has no streach

[tunnels]

any core ..by itself is worthless..including balsa..take a piece and "whack" it on the side of your workbench and see what happens.

Now skin both sides of it in glass and try it.

do the same with foam and c/f and get back to me with the results.

How many boats have you repaired over the years ? How many boats have you made ? reguardless of size , power of sail !
How many lives have depended on the work you have done to come home safely every day ,many times a day in conditions that life savers get seriously hurt in?.
Do you check your tyre pressure on your car by just kicking the tyres ?
Is wacking any kind of core on the corner of a bench the official cerified test done by the laboritory
She'll be right mate !! we have the best coast guard service in the world just make sure your boats a bright color so they can find ya !!

[mrconcrete]

"Kevlar is going down first because of the impact resistance, then the carbon for strength."

Need to take a step backwards and sit and think about whats been written.
Impact! but from what ? impact as in hitting a rock or hitting a log ? or Water impact from waves big or small ?
Theres are two completely differnate kinds of impact resistance !!

Carbon for strength . How do you interpret the strenght of the carbon on the inside laminates what is it doing to give it strenght ??
Point remember here is carbon has no streach

Because that is the best method for the materials that I am using.

And thats 100 times better than the kids at the factory built them 30 years ago.

With that being said, don't you think it will work just fine?

[mrconcrete]

How many boats have you repaired over the years ? How many boats have you made ? reguardless of size , power of sail !
How many lives have depended on the work you have done to come home safely every day ,many times a day in conditions that life savers get seriously hurt in?.
Do you check your tyre pressure on your car by just kicking the tyres ?
Is wacking any kind of core on the corner of a bench the official cerified test done by the laboritory
She'll be right mate !! we have the best coast guard service in the world just make sure your boats a bright color so they can find ya !!

Go read this thread and get back to me..
http://www.yellowbullet.com/forum/sh...d.php?t=197083
I drag race..some of the fastest cars in the USA have my fingerprints all over them.

Boats are just a hobbie.....BUT...I figure I would take my skills that I have accumulated over the years and apply it to the boat I once owned as a kid.

Anytime you want to match your engineering skills I'm ready.

What record(s) if any do you hold again?

Sory to be blunt but thats the vibe I am getting

Bill Diehl

[tunnels]

Because that is the best method for the materials that I am using.

And thats 100 times better than the kids at the factory built them 30 years ago.

With that being said, don't you think it will work just fine?

I Know what you are saying and yes what was used years ago has stood the test of time reguardless of there workmanship of the times and the way they were made .
Since the drift (slowly )has been to trying to save weigth and make things go faster than they were ever designed to go and use materials that had never even been thought of when the boat was first build , the repair and re-strengthing thing is a major problem . Dont get me wrong theres many ways of doing certion jobs but its the unsuccessful ones that everyone remembers .
What i have learned over the years of messing about in boats i try to pass on to others , I travel to lots of places to training staff and showing companies what works and what they are doing wrong .
many things have changed but the problems have stayed the same as we had 25 years ago . Theres a wealth of knowledge and exsperiance out there but finding it is not easy . Every one has a story to tell and most stories have things we should learn from but it never happens .
Everything i write about on this site is from what i have seen and done and i know what works and what dosent ! Everything has it limitations and what it can be used for as well as what it shouldnt be used for !!
There always a miss understanding factor that you have to be careful of i have found as well !

[mrconcrete]

I Know what you are saying and yes what was used years ago has stood the test of time reguardless of there workmanship of the times and the way they were made .
Since the drift (slowly )has been to trying to save weigth and make things go faster than they were ever designed to go and use materials that had never even been thought of when the boat was first build , the repair and re-strengthing thing is a major problem . Dont get me wrong theres many ways of doing certion jobs but its the unsuccessful ones that everyone remembers .
What i have learned over the years of messing about in boats i try to pass on to others , I travel to lots of places to training staff and showing companies what works and what they are doing wrong .
many things have changed but the problems have stayed the same as we had 25 years ago . Theres a wealth of knowledge and exsperiance out there but finding it is not easy . Every one has a story to tell and most stories have things we should learn from but it never happens .
Everything i write about on this site is from what i have seen and done and i know what works and what dosent ! Everything has it limitations and what it can be used for as well as what it shouldnt be used for !!
There always a miss understanding factor that you have to be careful of i have found as well !

Thanks....Thats why I posted..I want the pros and cons

[Riverman]

Knowledge about building cars does not translate to boats. Aircraft yes but not cars. Listen to the knowledge here and build it right and light. Exotic fabrics are not needed.

Think of the core as the web of a I-beam and the inner an outer skins as the flanges. The deeper the web the greater the resistance to bending - same with core - the thicker the core the better.

Wood (balsa) works fine, lots of pros still use it. It will last if it is installed and encapsulated properly.

[tunnels]

Knowledge about building cars does not translate to boats. Aircraft yes but not cars. Listen to the knowledge here and build it right and light. Exotic fabrics are not needed.

Think of the core as the web of a I-beam and the inner an outer skins as the flanges. The deeper the web the greater the resistance to bending - same with core - the thicker the core the better.

Wood (balsa) works fine, lots of pros still use it. It will last if it is installed and encapsulated properly.

Thank you Riverman !!

The mixing of materials is not a good thing specialy kevlar,and carbon as well as glass that the hull was origanlly made from .
Cores are another touchy subject as you can see !

Simple is best always !

[tunnels]

Someone some where is going to ask why no stringers ! any one know why ?? Anyone what to take a guess??

No takers ! - OK so i'll will answer the question anyway .
The bottom of hulls need to move ! no i hear you say , yes i say it should be able to move !! and you would be amazed at how much some hulls move up and down , the faster you go the more it moves and the quicker it moves .
This movment helps absorb shock loadings such as hitting waves at speed !.
Wham and the boat goes upwards in a big hurry , During that wham the bottom will have absorbed a good part of the shock before the rest of the boat heads for the sky . Its this micro second of shock thats the killer!!
loads on the whole bottom of the hull are horrendous.
This is where poor workmanship begings to show up .
Poor choice of materials as thing begin to break and tear apart .
If you have a mixture of materilas such as kevlar and carbon then you have even more problems because you will have a harder riding boat and the carbon is trying very hard to do what it does best NOT STREACH and hold the panel ridged .
If you have stringers as well then they have divided the panel size into even smaller areas and makes the boat even harder riding and the loads on the carbon even higher .

Lets back up a little and make a total glass lay up !
Now have a material that will streach and allow the bottom to bend and absorb shock plus recover very quickly hence the uindirectional on the very inside of the layup .
The angle that the uni glass strands runs at is critical to make the bottom stiff , the shorter the strands of glass the less streach ,the stiffer the panel will be ! make sense ?
In this case all the glass is working together because we have simular materials all working with simular charictoristics !!.
If you were to add a layer of carbon as the inside layup then all the stress is thrown directly onto the carbon layer and it wont be to long before something started to give , the ride in the boat would be very hard !!
Adding a stringer could be a advantage but the placement and the size would have to be thought out carefully . Its not the width thats the problem its the height! The higher the less bend so the stronger the top edge of the stringer has to be or as the hull loads and starts to bend the stringer is trying to stop that bend not only in a localised place on the hull but over the total length of the stringer and so it to has huge loads imposed on it in differant places .
Personally i would leave the stringer out and get a slightly softer ride and a hull that would take more shock loading spread over a bigger area and hence a more duable hull .

A good way to demonstrate the movement between the top and bottom surfaces of a laminate is to use a thick telephone book and lay it flat slightly over the edge of a table , grip the two edges tight and the bend the book over the edge of the table . See how far the upper cover of the book moves ! Same applys to the glass layers in the hull The tighter you grip the book the harder it is to bend over the edge , Once you have bent the book still holding tight try to laythe book flat again, see what happens to the pages inside , they will have separate from each other , This is why you need a good core one the does not shear , Balsa !!

This subject could could go no for hours !,so if there are still any questions please ask!

[Brabender]

Tunnels very interesting

PS I think I may have been on one of your projects last winter
Maritani X in the Bahamas. Was built in New Zealand, Know it?

[afr]

tunnel none of these guys are fiberglass engineers dude there just workers and back yard hobbiest
you know what im sayin
no offence

[commuter boats]

Someone some where is going to ask why no stringers ! any one know why ?? Anyone what to take a guess??

No takers ! - OK so i'll will answer the question anyway .
The bottom of hulls need to move ! no i hear you say , yes i say it should be able to move !! and you would be amazed at how much some hulls move up and down , the faster you go the more it moves and the quicker it moves .
This movment helps absorb shock loadings such as hitting waves at speed !.
Wham and the boat goes upwards in a big hurry , During that wham the bottom will have absorbed a good part of the shock before the rest of the boat heads for the sky . Its this micro second of shock thats the killer!!
loads on the whole bottom of the hull are horrendous.
This is where poor workmanship begings to show up .
Poor choice of materials as thing begin to break and tear apart .
If you have a mixture of materilas such as kevlar and carbon then you have even more problems because you will have a harder riding boat and the carbon is trying very hard to do what it does best NOT STREACH and hold the panel ridged .
If you have stringers as well then they have divided the panel size into even smaller areas and makes the boat even harder riding and the loads on the carbon even higher .

Lets back up a little and make a total glass lay up !
Now have a material that will streach and allow the bottom to bend and absorb shock plus recover very quickly hence the uindirectional on the very inside of the layup .
The angle that the uni glass strands runs at is critical to make the bottom stiff , the shorter the strands of glass the less streach ,the stiffer the panel will be ! make sense ?
In this case all the glass is working together because we have simular materials all working with simular charictoristics !!.
If you were to add a layer of carbon as the inside layup then all the stress is thrown directly onto the carbon layer and it wont be to long before something started to give , the ride in the boat would be very hard !!
Adding a stringer could be a advantage but the placement and the size would have to be thought out carefully . Its not the width thats the problem its the height! The higher the less bend so the stronger the top edge of the stringer has to be or as the hull loads and starts to bend the stringer is trying to stop that bend not only in a localised place on the hull but over the total length of the stringer and so it to has huge loads imposed on it in differant places .
Personally i would leave the stringer out and get a slightly softer ride and a hull that would take more shock loading spread over a bigger area and hence a more duable hull .

A good way to demonstrate the movement between the top and bottom surfaces of a laminate is to use a thick telephone book and lay it flat slightly over the edge of a table , grip the two edges tight and the bend the book over the edge of the table . See how far the upper cover of the book moves ! Same applys to the glass layers in the hull The tighter you grip the book the harder it is to bend over the edge , Once you have bent the book still holding tight try to laythe book flat again, see what happens to the pages inside , they will have separate from each other , This is why you need a good core one the does not shear , Balsa !!

This subject could could go no for hours !,so if there are still any questions please ask!

What planet did you step off from !! I think you are a bit to carried away with all your mumbo jumbo and need to simply get back to plain simple basics .

Grass roots and simple methods are what it all about when it gets confussing then you end up with problems and things falling apart . workmanship at the end of the day is where more that 80% of the problems stem from . I have traveled to differant countries to work and teach and seen the same problems over and over again , it never changes .

Yeah! think and do the job properly ,Take the next step and use vinylester resins to doyour repairs with ,makes it just that little better than using polyester . KEEP it simple !! its not rocket science to wet out fibregalss with catalysed resin and you dont need a engineering degree ! its simple common sense and dosent take a university degree . Come on think simple !!!!

OK

[tunnels]

Sorry !!!! get a little carried away at times .
If you see something thats damaged from just everyday use then you have to ask your self why and how did this happen .
If you cant visulise what would make this happen then you will never know how to prevent it from happening again ! right ?.

Over night iv'e thought about why a lot of the Balsa cores in the boats you guys repair are 1/2" and not 3/4" like i would exspect . Its helps to make the hull move a little and gives a slightly softer ride combined with the shape of being slightly concaved from chine to keel , the age old philosaphy shape =strength Without added weight !

Sorry for thinking ! i will tie my fingers together so i cant type anymore

[afr]

no big deal tunnels i know what your sayin
but you should have seen some of these boats you would have never thought they would have made it threw there first sea trial
its all good dont worry about it

[tunnels]

I love what i do ! i always like to study why things happen the way they do and not just listen to idle speculation from tie wearing narrow minded surposed experts . I have worked with so many really clever guys over the years and seen so many good ways of doing simple jobs !
Iv'e also worked with a bunch of idiots as well that only go to work to eat there lunch and get away from there Mrs and the kids each day and never learned a thing and never will .
I was even working in the company here in nz when Young America Yacht was repaired after snapping in half , This was the high end of a major failure and was a combination of things not just one . I spend hours going through all the damaged centre part of the boat silently asking why . as i said it was a combination of things and wasnt the first or the last as the Australians lost there boat the same way as did a coule of others . I was privelaged to meet and talk to the guys that worked doing the repair work from Geotz boat builders .
I was thrown in a surf life saving boat and taken out into the huge surf at our west coast beachs to see first hand what they did with there boats that used to fall apart and break just at the wrong time . High modulas had spec'd the special HD lay up that was unbreakable according to there engineer . It was quite simple to sort out really the boats had to be built flexable and go with the flow so to speak .I built a first boat to how i thought it should be, came out a lot lighter and using just one type of glass off the shelf and ordinary polyester resin with a heap of simple common sense ,from then on not one boat ever got dammaged or broke and the company has never changed that way of making there boats in the past 10 years .
The stories of learning goes on and on and i hope will never stop till i cant move any more .