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    • UnderDawg

      A Few Simple Rules   05/22/2017

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boatcat65

Kevlar Verses Fiberglass

78 posts in this topic

Seeing a number of race boats from the Kevlar era coming onto the market and wondering how history views them.  Given appropriate engineering did Kevlar really offer that much of an advantage?  How has it held up over time?  It's a part of history I guess I missed.  Thoughts on why we don't seem to see it any more? 

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Much more important, arguably, is epoxy versus polyester. Kevlar has some significant advantages, and one big drawback, but carbon is better in almost every respect and now affordable, which is why you don't see much Kevlar.

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so what is the big draw back ?

and is Kevlar showing any age issues ?

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compression strength (and moisture uptake)

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According to the Maestro, Betts doesn't like Kevlar hulls.

That's good enough for me.

I've heard that K "floats" in the resin too which sounds like bagging or infusion would be absolutely mandatory.

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Yes to the above. Kevlar is weak in compression but lots better in tension than similar E-glass fabrics. Compared to E-glass, the compression numbers were about 20% lower.

Its specific modulus (stiffness) is lots better than E-glass. So if you're designing a racing boat when carbon is banned, Kevlar is the next best option.

Its good with impact (bulletproof vests)

Its density is lower than epoxy resin so it does try to float. Bagging is mandatory.

It absorbs water easily.

When sanded it fuzzes up.

VO60s were built in Kevlar, as well as a generation of IMS racing boats because carbon was banned. Once carbon was allowed, everybody switched because it is so much better.

Interesting - I looked at Vectorply's database to see what plain Kevlar fabrics were still being made - only 5 weaves! It sure isn't very popular any more.

For an aged race boat I would be most concerned with water absorbing especially through deck fittings or in the bilges. I wouldn't be as worried about the low compression numbers because good designers would allow a bit more laminate to compensate. But a careful survey with a surveyor that is at the top of their game with racing boats would be warranted.

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Kevlar is much more expensive than carbon now. This was not the case in 1985.
Kevlar does "float" but that is not a problem if you vacuum bag. I've bagged it. I also didd a single kevlar skin over a wood core for a rudder and it worked fine. Haha.
Moisture uptake of kevlar fibers is 8% by weight -- not unlike its cousin nylon. But have you ever heard of this being an actual problem? I haven't.
Because you needed epoxy to build with kevlar, you get a nice epoxy hull, and the kevlar modulus is high, the laminate is not as likely to fatigue like a fiberglass-polyester laminate.
Kevlar is tougher than carbon but because you get so much more performance per pound out of carbon, that is what gets used now. Just do be aware that carbon hulls sacrifice toughness for lightness.

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Kevlar worked just fine on the inside layup on Western Red Cedar strip planked trimaran hulls. S-glass on the outside. Seemed backwards to me until I helped build one.

UP MY SLEEVE

Image result for JPEG

    Talk about tough! This was when she was recovered after months upside down after a capsize and abandonment in the Route Du Rhum.

Image result for Up my sleeve trimaran

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1 hour ago, fastyacht said:


Kevlar is tougher than carbon but because you get so much more performance per pound out of carbon, that is what gets used now. Just do be aware that carbon hulls sacrifice toughness for lightness.

I read an interview somewheres (Seahorse? '90's?) guy was on a boat in the Admirals Cup that got T-boned said he was glad it was kevlar and not carbon 'cause the carbon woulda' shattered.

So wouldn't a kevlar/carbon laminate be best 'o both worlds? Don't Hinckley do something like that? 

It was kevlar outer skin directly bonded to carbon inner. I saw a picture. Thought it was Hinckley, maybe not.

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When I worked for Bill Seeman (C-Flex and SCRIMP patent holder) in New Orleans, we were just starting to buy looms for making our own composite fabrics and considered doing a hybrid weave of carbon.kevlar such at this. Glad to see it is still around.

 

Image result for carbon kevlar hybrid cloth

Product Description

Carbon Fibre / Kevlar® Hybrid fabric, 210gsm, 2/2 twill weave at 1.2m wide.

This fabric combines the properties of 2 unique reinforcement yarns. Carbon provides high levels of stiffness and strength, whereas aramid provides huge impact/abrasion/fracture resistance. The aramid used in this cloth is genuine DuPont Kevlar®. This distinct looking hybrid cloth is used in many high-performance, high-impact applications such as canoes, military ballistics and rally-car panelling.

Carbon/Kevlar® fabric can be used in just the same way as standard carbon fibre. It is suitable for use in wet-lay, vacuum bagging and resin infusion manufacture as well as for use as a single surface layer where parts are being made to look like carbon/Kevlar® (skinning).

When using only carbon/Kevlar® reinforcement in a part you should expect to use several layers of this fabric in each part. None-structural components like body panels and covers will typically require 3-6 layers of a carbon fibre cloth of this weight.

 

 

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Hybrid laminates are inherently inefficient. The higher modulus material carries all the load until it ruptures. You can design this to form a quaasi-ductility for collision but you end up carrying extra weight around.
Some hybrids are warp = one material, weft = other. In this case, you have a different form of anisotropy and again it is typically less efficient but can be cleverly designed to increase toughness without a large weight penalty.

Because Kevlar 49 and the less expensive Carbon have similar moduli EDIT: I had to refresh my memory on this -- 16 MPSI k49 vs 33 MPSI carbon. NOT so close. But closer than fiberglass and carbon), they tend to load up more equally, allowing for some more efficient hybrids. But you still break the carbon first, followed by the kevlar in a cascading failure. Because Kevlar 49 has higher UTS and much higher elongation, it is tougher, but in a hybrid it is considerably less tough than by itself, because when the carbon goes, it suddenly sheds all that load to the remaining kevlar----

Perhaps the best place to look at hybrids is fashion textiles. The strengths achieved with poly-cotton are not simple ratios. You can make everything weaker if you don't get the ratios, twist ratios, and other details correct. Yacht design doesn't have the budget to do the analysis required to get good results with this kind of sophisticated stuff. That doesn't mean people don't try it and sometimes get good results.

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It shore is pretty though with clearcoat! 

Image result for carbon kevlar hybrid cloth

Fast, what is your take on this stuff?

Image result for carbon kevlar hybrid cloth

 

 

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3 hours ago, Zonker said:

...Kevlar is weak in compression but lots better in tension than similar E-glass fabrics. Compared to E-glass, the compression numbers were about 20% lower.

...

Its good with impact (bulletproof vests)

 

I'm confused with this. Isn't impact compression?

I know that in the '80s when I would hit a Kevlar composite structure with a hammer, it would dent instead of crack. I thought that was pretty cool. Isn't still used on places like the bow and the leading edge and bottom of keels?

 

 

 

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I thought it would be useful to explain in simple terms the mixture rule.
Let's take two fibers, each the same diameter, one at 10 and the other at 20 = modulus.
Let's strain the system 1%

The 20 modulus will have a force of 0.2

the 10 modulus will have a force of 0.1

Total force = 0.3

The higher modulus fiber is carrying 67% of the load.
Let's say the strain to failure of the 20 modulus fiber is 3% and the 10 modulus is 6% so that they have equal breaking strengths. When the higher modulus fiber fails, all the load sheds to the other fibers, which are already carrying 1/3 of the load...so when the stiff fibers fail, the limber fibers will then go past their breaking strength too. If they are stronger, then they could carry the ultimate load. This is just a thought experiment and the loads are contrived.

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Fastyacht - your example is not misguided.  This is similar to the often-cited cause of several of the rudder failures involved in the tragic 1979 Fastnet race.   Some of the boats had "hybrid" rudder stocks,  made of an aluminum tube wrapped in Carbon reinforcement - problem was that (aside from the troublesome galvanic implications in the long-term)  the aluminum is very flexible(yet 'tough') ,  relative to the Carbon - and so contributed little to the 'strength' of the carbon - which,  being " stiff "  that means -  also rather brittle,  and when over-stressed,  fractured and then-on contributed nothing to the stiffness of the aluminum, which then failed shortly thereafter.

Basically the materials work different shifts and in the working environment were not complimentary in any practical sense.

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Kevlar also does not like repeated long term flexing. The fibers start to fracture.

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That is why we used the Kevlar on the inside of the red cedar strip planking so any impact would be putting the Kevlar into tension. There might be a puncture through the S-Glass skin and come crushing of the cedar core but the inner layer of Kevlar was the last line of defense against holing. Seemed to work for that boat. 

 

Fast, here is some info on the Texalium.

 

 

(TXS85 Twill) 3K 8.51oz/241g  0.013" Thick   50" wide 
Silver Carbon Fiber  aka Silver Texalium 
Above Left: TXS85 Twill Weave 
 Silver Texalium aka Silver Carbon Fiber

is actually aluminum coated 2X2 Twill 
woven fiberglass. It is extremely popular 
since it is low cost and still gives that 
beautiful twill carbon fiber weave look
. 
This fabric is virtually identical in
 weave size, spacing and looks to our 100% Carbon 2X2 Twill weave, but in silver. Shown and sold in Silver, this fabric is excellent for aesthetic overlay work.

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1 hour ago, Somebody Else said:

...Kevlar is weak in compression but lots better in tension than similar E-glass fabrics. Compared to E-glass, the compression numbers were about 20% lower.

...

Its good with impact (bulletproof vests)

 

I'm confused with this. Isn't impact compression?

I know that in the '80s when I would hit a Kevlar composite structure with a hammer, it would dent instead of crack. I thought that was pretty cool. Isn't still used on places like the bow and the leading edge and bottom of keels?

no, compression and tension relate to the way the fiber is loaded, in tension you stretch it, in compression you try to make it shorted.

 

impact relates to the ability to absorb energy while getting broken.

strength related to the ability to hold a large load.

 

so in your example hitting with a hammer involves both impact and flexural loads (compression on concave surface and tensile on back surface)

good impact resistance is what makes it dent rather than crack, (and by denting it also reduces the peak load during the impact)

straight strength involves static loading (take your hammer and push really really hard :) )

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Gotta love the expertise available here!  So it seems an older Kevlar hull might not be a bad foundation/beginning for a performance oriented cruiser based on an older racer- tough, better than e glass, will have epoxy instead of polyester.  Seems the main downside is it's sub-optimal in todays market re: cost and weight.  Water absorption could be an issue, I assume not so much of a potential challenge with foam cores but balsa could be a problem?

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Unless you can find verifiable actual *structural* issues with "water absorption" I wouldn't worry about that. Gaining 8% weight to the 45% (or less) of the laminate that is kevlar just isn't important.
With rare exceptions, kevlar boats were vacuum bagged epoxy. No voids, no place for vapor to condense, no pox issues. There were some vinylester boats but again vacuum bagged.
The oldest production kevlar boat was a center console motorboat. Proline? Maybe another maker from the day beginning with S? Can't remember for sure.
Oldest production sailboat: the first batch of Tasar dinghies. Yep. It is true. early 1970s.
Most of the sailboats were custom race boats over male plugs.
One famous example of having to start over after a bad batch of epoxy 9more likely a screw up with mixing ratios): SNAKE OIL built at Annapolis Custom yachts. All kevlar, the first hull sat ignominiously in the yard after the resin didn't kick. As I remember, the actual finished boat was also kevlar.
There were all sorts of hybrid carbon kevlar IOR boats. Jack King's German Frer's IOR 50 "MERRYTHOUGHT" (all his boats had that name so beware) built in 1986 also at ACY was carbon-kevlar over rigid PVC foam (Kleg, Divi I forget which--they were separate companies back then).
The hulls on these boats were obscenely light. SNAKE OIL weighed under 1000 lbs for just the hull. I can't remember the exact number.

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6 hours ago, Zonker said:

 

Its good with impact (bulletproof vests)

 

This very much depends on the grade of Kevlar, race boats were never built using ballistic grade Kevlar. 

 

That was just a sales pitch used to promote the use of material. 

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Also "bulletproof" is mostly due to the textile nature. Once you put resin inot the system that goes away.

Take a piece of 3 oz plain weave kevlar if you can find it. try to tear it. You can't. wet it with epoxy and cure. Tears easier than a piece of cardboard.
On the other hand, I had a carbon kevlar tiller extension. The first time I broke it, it stayed in one piece with a "hinge". The resin around the kevlar mercifully pu,lverised while the carbon broke. I was able to reinforce it. Not so luck the 2nd time, but that time it broke at an earlier all-carbon patch :-(. It is still on the bottom of Long island Sound.
If anyone finds a strange looking black and gold pattered "broomstck" please let me know. I'll even pay you $50 for it.

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Thanks.  This is the sort of thing I'm looking at:  http://www.yachtworld.com/boats/1997/Goetz-Custom-Boats-Farr-49-3106875/San-Diego/CA/United-States#.WWhgy4WcFfx 

It seems that hull/keel/rig and another $100K and some of my labor could put together a pretty sweet cruising boat- something close to or even besting a Santa Cruz 52 in performance and accommodation, but at half the price.  We'll see.

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6 hours ago, boatcat65 said:

Thanks.  This is the sort of thing I'm looking at:  http://www.yachtworld.com/boats/1997/Goetz-Custom-Boats-Farr-49-3106875/San-Diego/CA/United-States#.WWhgy4WcFfx 

It seems that hull/keel/rig and another $100K and some of my labor could put together a pretty sweet cruising boat- something close to or even besting a Santa Cruz 52 in performance and accommodation, but at half the price.  We'll see.

That's a lot of spreaders to mess with to keep that stick in line. 

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10 hours ago, boatcat65 said:

Thanks.  This is the sort of thing I'm looking at:  http://www.yachtworld.com/boats/1997/Goetz-Custom-Boats-Farr-49-3106875/San-Diego/CA/United-States#.WWhgy4WcFfx 

It seems that hull/keel/rig and another $100K and some of my labor could put together a pretty sweet cruising boat- something close to or even besting a Santa Cruz 52 in performance and accommodation, but at half the price.  We'll see.

A bit of a stretch even if it's ALL your labour. and not just SOME of your labour

Once a yard is involved, a SC 52 is probably a cheaper option.

And in the end, it may not have much value on the market because it still won't be a SC 52.

As Darth said. a rig like this one is not really conducive to cruising.

My philosophy on boat buying is that if the acquisition cost of a sailboat is a major consideration for the buyer, then operating costs will prove to be killers.

But it's always fun to fantasize...

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If you want a high performance racer/cruiser just get a well maintained Lapworth 36; if you put $50k into that you will have a bullet proof, fast boat with a nice comfortable interior (probably more usable volume than the 49 footer pictured), no runners to worry about and $50k leftover for a watermaker, an icemaker and rum.

 

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That would be a dreadful cruiser. I wouldn't touch it. Boats like that were designed and built to win a few races then fall apart.

There are so many negatives.- fragile rig, poor head room, mandatory runners, cockpit too big, likely soft hull and on it goes.

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16 minutes ago, savoir said:

That would be a dreadful cruiser. I wouldn't touch it. Boats like that were designed and built to win a few races then fall apart.

There are so many negatives.- fragile rig, poor head room, mandatory runners, cockpit too big, likely soft hull and on it goes.

+1

I was trying to imply the same thing - but being less straight forward about it

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It would be like buying an old Formula One car to use as a daily driver.

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I think cruising it would be a nightmare, this is a syndicate boat for four guys to use on Wednesday nights.

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12 hours ago, boatcat65 said:

Thanks.  This is the sort of thing I'm looking at:  http://www.yachtworld.com/boats/1997/Goetz-Custom-Boats-Farr-49-3106875/San-Diego/CA/United-States#.WWhgy4WcFfx 

It seems that hull/keel/rig and another $100K and some of my labor could put together a pretty sweet cruising boat- something close to or even besting a Santa Cruz 52 in performance and accommodation, but at half the price.  We'll see.

Free is too much!

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That is a fantastic day racer. And Eric Goetz built the very best.
Cruising? What? Are you crazy? Then again I cruised a dinghy .... so I guess you could. But putting an interior in it? That's just wrong. Haha.

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A SC52 with full and newish cruising and racing sail suits and all the kit can be had for under $300k 

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Heh heh... by "cruising" I mean a couple weeks at a time, not consistently offshore.  Yes, the rig would get cut down to a masthead, maybe add a couple of feet to put the spin halyards in the clear, ditch the overlapping headsails, just fill out the interior a bit.  It would still be fast but much simpler.  On the other hand you guys are correct- there's lots of choices within a $150K purchase budget with some left over for the inevitable.  But....I really don't just want an average boat- something different from what most are sailing always appeals.  Don't really give a rip about resale- boating has never made me any money!  ;-)

 

My wife wants something like a Beneteau 45F5- not a bad boat but so much wood and furniture.  I'm struggling...

 

 

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13 hours ago, boatcat65 said:

"JAVELIN (Ex: BREEZE) is a donation vessel that is being offered as a three-year bareboat charter with purchase option."

There is  Reason it's  a donation.

I've sailed on the boat. I love the ergonomics of this boat. It is very fun to race. It is the same generation as the Farr 40 and Farr (Mumm) 30--rigged the same and sailed pretty much the same. That said, it has struggled to perform to its potential. It was bought by Fell as a salvage (I believe) with serious damage to the port side of the hull. The repair was done very well and shows no sign of any problems but you can definitely see the extent of the repair through the interior clear resin. Then several years ago it hit an unmarked rock at the entrance to the Coral Marina in Ensenada, MX. This is the 2nd time the insurance totaled the boat. The owner took the settlement and put it back into the boat in the form of a new Andrews bulb keel and rerigged it for masthead kites and the sprit, addressing the downwind speed deficit Javelin has suffered since the end of the IMS for which the boat was designed. Still the boat struggles to perform. Upwind it is very fast but downwind continues to be a bit of a problem.

Built as a racer only with basically no accommodation for cruising, it has sail-control running rigging criss-crossing the interior. Setting it up for cruising would entail pretty much re-engineering all the sail controls. You have essentially an over-canvassed basis for short-handed sailing. A more practical rig with sails to suit would push the price of this boat well past anything that could be considered a bargain. This is not the boat you are looking for unless you plan to race it. It's still questionable for that...

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Damm- that's too bad- seemed like a deal for a decent hull, carbon rig, updated keel, etc.  A good start on a project, plenty of which I've successfully completed.  If someone would put a Santa Cruz 50 up for sale I'd probably be all over it.  Just not interested in hull #1 currently for sale- needs to be a later edition, all glass, maybe some updates.

 

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5 hours ago, boatcat65 said:

Heh heh... by "cruising" I mean a couple weeks at a time, not consistently offshore.  Yes, the rig would get cut down to a masthead, maybe add a couple of feet to put the spin halyards in the clear, ditch the overlapping headsails, just fill out the interior a bit.  It would still be fast but much simpler.  On the other hand

My wife wants something like a Beneteau 45F5-   I'm struggling...

You don't have a fucking clue about any of the practical realities of doing ANY of this,  do you ?

 

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23 minutes ago, Great Red Shark said:

You don't have a fucking clue about any of the practical realities of doing ANY of this,  do you ?

 

If he wants to grab a trans am, put a 1600cc four cylinder motor in it and change out the mags for skinny bicycle tyres for economy, then so be it!

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I love the magical "Just lop a couple feet off the mast and boom" types - who have some mysterious ability to re-bond the ENDS of the spars back into working equipment - look,  if it were EASY,  somebody smarter than YOU would have done it by now.

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Actually I do have a clue, a fair amount of relevant education, and more fabrication experience than most but not all.  What I don't have is a clear decision about what I want in my next toy.  Yeah, I can go buy a 50' Beneteau but the phrf of 60 or so isn't as exciting as something more unusual with a rating that ends up closer to zero.  Guess I don't see a new masthead as that much of a challenge- hell, a piece of aluminum pipe with some fittings welded on slipped down over the stump will keep the stick up even if it isn't very elegant.  Not that it would be my solution.  Anyway, something interesting will turn up.  I'd like to have it by fall so we could work on it over the rainy season.  Appreciate all the positive feedback from those who clearly know their stuff.

 

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2 hours ago, boatcat65 said:

Actually I do have a clue, a fair amount of relevant education, and more fabrication experience than most but not all.  What I don't have is a clear decision about what I want in my next toy.  Yeah, I can go buy a 50' Beneteau but the phrf of 60 or so isn't as exciting as something more unusual with a rating that ends up closer to zero.  Guess I don't see a new masthead as that much of a challenge- hell, a piece of aluminum pipe with some fittings welded on slipped down over the stump will keep the stick up even if it isn't very elegant.  Not that it would be my solution.  Anyway, something interesting will turn up.  I'd like to have it by fall so we could work on it over the rainy season.  Appreciate all the positive feedback from those who clearly know their stuff.

 

Then I guess there is no need to point out that the boat in question has a CF rig.

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Right.  Sarcasm.  The carbon rig is one of the attractions, especially given the price.  The only change would be a new backstay termination point.   Not everything has to make sense.  What else do you do with a boat that nobody wants, either because its beat, or completely uncompetitive, or too expensive to maintain in full fashion?  Seriously- what would this have cost to build back in the day- $600K?  And now $40?  Chop it up for parts, or try to see how some experiment works out?  It doesn't have to be kept as some beacon of perfection- those days are done.  But it can be enjoyed in a different way.  Just kicking ideas around.

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Sarcasm?

Only in the sense that anyone with a clue would know that CF and aluminum do not play well together.

What else do you do?  You could race and/or weekend the hell out of it until enough things break that the boat can't sail anymore - then part it out.  You may even make some money on the deal.  

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On 7/13/2017 at 6:59 PM, boatcat65 said:

Gotta love the expertise available here!  So it seems an older Kevlar hull might not be a bad foundation/beginning for a performance oriented cruiser based on an older racer- tough, better than e glass, will have epoxy instead of polyester.  Seems the main downside is it's sub-optimal in todays market re: cost and weight.  Water absorption could be an issue, I assume not so much of a potential challenge with foam cores but balsa could be a problem?

My background is 30 years of R/C sailplane contests. I was very active in building vacuum bagged sailplanes and some of what we saw doesn't match what is being quoted from the spec sheets.

  First of all we found that both E-glass and and S-glass were both stronger in compression and tension than Kevlar and had double the lifespan when flexed repeatedly for thousands cycles in a normal range of motion. The reason this is different than the spec sheets is that the glass cloth gets fully penetrated when wet to hold it's orientation. Kevlar seems to absorb epoxy only on the surface of the fibers, while the core remains dry and flexible.  Think about it like a hard boiled egg in tube form. This is both good and bad depending on where it's used. The place that really shines with Kevlar is abrasion resistance and the ability to flex 50 degrees when used as a skin hinge. The way Kevlar protects is by the epoxy skin cracking to absorb the impact then the soft core fibers flex and hold the larger components together.

  So if we were bagging a an "outlaw" dagger board for a Sunfish, I would put two layers of 6 oz E-glass cloth on the foam core followed by a layer of 4 oz E-glass cloth at a 45 degree bias to the 6 oz. Then I would put a  2" wide strip of .014" carbon uni-web or tow lengthwise at the thickest part of the foil (3" from Leading edge ?) followed by a 1.4 oz glass "finish" cloth . The last step would be the Kevlar  1 " wide strip wrapping the leading edge and a small extra patch at the bottom where it will drag through the gravel when bottomed. The Kevlar being the over the 6 oz allows you to repair the fuzzy damaged Kevlar buy re-wetting with thin CA (super glue) and a light spray of kicker, (aerosol catalyst) . If the Kevlar was the inner layer, the CA would melt the foam core as would any Polyester product.

They way I think of it is the carbon uni-web is 10 times stronger in compression and triple in tension, so it's what you stand on the right a capsize. The 45 biased cloth resist tearing and adds torsional flex to prevent "humming" and the Kevlar drags through the sand.

I would expect an older Kevlar boat to flex like a boogie-board.

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My only experience with Kevlar was 35 years ago.  We were vacuum bagging racing canoes/kyaks out of 1/16" cedar veneers and epoxy over male molds.  We tried Kevlar on the bows for abrasion protection.  Most miserable stuff I've ever worked with- floats, hell on tools, very difficult to finish.  Never used it again.

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If you have never worked on a boat before, as in built an interior or rebuilt a major part of the hull/deck then you are in la la land. To convert this boat to something that your wife will enjoy and not endure will cost you an interior, headroom, rig and layout changes that all add up to year(s) of work. Even if this boat was free I would not take it to do what you intend to do with it.

Take cutting the rig down, since its CF you will need to be familiar with the material and the engineering required to get a safe result that still performs. How are you going to do that, lop the top off then rebuild the crane? Fine then you'll need to fabricate one to fit, welcome to vacuum bagging and the associated CF skills, then you'll need to design your backstay attachment which no doubt will require work on the hull reinforcing the chainplate area. Factor in a new backstay and forestay plus a new main which is now going to have a different c/e and poof! the performance you crave is out the back door. Meanwhile your wife is moaning about no shower or hot water and having to clamber around the wheel and into the cavelike interior. No matter you can fix all that but its going to add about 800kg of shit and cost you another 35k if you do it all yourself or 80 if you pay for help.....and its a budget job I'm quoting.  In the end youll have a odd ball dog that will be a faster than average cruiser but a slow race boat, and a shitty cruiser with the home comforts of a sportsboat. And its old and everything is getting fucked and worn out.  Resale value after all that is half of what you paid for it intially.

But youre a smart guy who has an awesome skill set so dont let me stop you turning an old thrashed raceboat into a cruiser, imho clearly you havent got the coin to buy a good cruiser racer but thats what I would do or a possibly cheaper option is to get another wife who doesnt mind hanging on the boys boat, drinking rum, sleeping in wet spinnakers and shitting in a bucket.

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Jim Betts and I discussed Kevlar for the carbon cutters. He won't get near it.

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Well Kevlar certainly doesn't seem to be everybody's favorite material.  Too bad- I like the idea of a light, simple boat and rehabbing an older racer still has some appeal.  Will probably end up with an X-442, Bene 45F5, 47.7 or similar.  A Santa Cruz 50 (or 52 in the $225-250 range) would be perfect- just gotta be patient, somebody will want to sell soon enough.  Don't really need all the furniture the others offer- my wife is much more competitive, an athlete, would rather go fast and is much less concerned about color coordinating the towels in the head and all.  Gotta love Sailing Anarchy- lots of opinions, plenty of competence, and always some crap just for the hell of it!  :-)

 

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On 7/14/2017 at 0:38 PM, Somebody Else said:

"JAVELIN (Ex: BREEZE) is a donation vessel that is being offered as a three-year bareboat charter with purchase option."

There is  Reason it's  a donation.

I've sailed on the boat. I love the ergonomics of this boat. It is very fun to race. It is the same generation as the Farr 40 and Farr (Mumm) 30--rigged the same and sailed pretty much the same. That said, it has struggled to perform to its potential. It was bought by Fell as a salvage (I believe) with serious damage to the port side of the hull. The repair was done very well and shows no sign of any problems but you can definitely see the extent of the repair through the interior clear resin. Then several years ago it hit an unmarked rock at the entrance to the Coral Marina in Ensenada, MX. This is the 2nd time the insurance totaled the boat. The owner took the settlement and put it back into the boat in the form of a new Andrews bulb keel and rerigged it for masthead kites and the sprit, addressing the downwind speed deficit Javelin has suffered since the end of the IMS for which the boat was designed. Still the boat struggles to perform. Upwind it is very fast but downwind continues to be a bit of a problem.

Built as a racer only with basically no accommodation for cruising, it has sail-control running rigging criss-crossing the interior. Setting it up for cruising would entail pretty much re-engineering all the sail controls. You have essentially an over-canvassed basis for short-handed sailing. A more practical rig with sails to suit would push the price of this boat well past anything that could be considered a bargain. This is not the boat you are looking for unless you plan to race it. It's still questionable for that...

Anybody the original name of the boat when it was built?

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9 hours ago, ExOmo said:

Anybody the original name of the boat when it was built?

 

Design #415 "Breeze" built in 1997 for the Italian Admiral's Cup team. There were about 5 boats built as variations on this design, mostly for Admiral's Cup competition. Slight changes in rig, deck layout, and ballast were incorporated to meet the wishes of the various owners.

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21 hours ago, Bob Perry said:

Jim Betts and I discussed Kevlar for the carbon cutters. He won't get near it.

Interesting. I had a Kevlar Poke Boat (kayak) and it was great. Strong and incredibly light. I was so impressed with it that I built several model yachts using Kevlar, all pretty successful. I use Aerospace Composite Products epoxy, which seems to have no problem wetting Kevlar.

I'm building one now, and RG65 which is Kevlar over Depron foam sheet, using the so-called "German Latex" method. You make a male mold out of wood, stretch a layer of latex sheet over it and staple it in place. Then staple down the cloth, coat with epoxy, and stretch and staple another latex sheet over that to squeeze the resin into the cloth. Kind of a poor man's vacuum bagging.

Cheers,

Earl

 

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3 hours ago, Earl Boebert said:

Interesting. I had a Kevlar Poke Boat (kayak) and it was great. Strong and incredibly light. I was so impressed with it that I built several model yachts using Kevlar, all pretty successful. I use Aerospace Composite Products epoxy, which seems to have no problem wetting Kevlar.

I'm building one now, and RG65 which is Kevlar over Depron foam sheet, using the so-called "German Latex" method. You make a male mold out of wood, stretch a layer of latex sheet over it and staple it in place. Then staple down the cloth, coat with epoxy, and stretch and staple another latex sheet over that to squeeze the resin into the cloth. Kind of a poor man's vacuum bagging.

Cheers,

Earl

 

I am NOT Googling 'German latex'.  Nope nope nope.

 

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Related question: for a while it was fashionable to wrap kevlar around a carbon spinnaker pole at the point here it would impact the forestay. Is that pointless?

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Wrapping the pole would help limit the damage from chafe against the headstay.  Not sure if it's that much more effective to have Kevlar instead of just glass, UHMW, etc.  Good on a weight basis?

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7 hours ago, boatcat65 said:

Wrapping the pole would help limit the damage from chafe against the headstay.  Not sure if it's that much more effective to have Kevlar instead of just glass, UHMW, etc.  Good on a weight basis?

That makes perfect sense, thanks!

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I've been looking at a fairly new (to me) fiber cloth for composites made of Basalt. Sound a lot like what we used to call 'Rock Wool' but is available in woven form now. I get the impression that it can replace E-Glass and provide much better abrasion resistance. I'll post what I can find.

A hard, dense volcanic rock that can be found in most countries across the globe, basalt is an igneous rock, which means it began in a molten state. For many years, basalt has been used in casting processes to make tiles and slabs for architectural applications. Additionally, cast basalt liners for steel tubing exhibit very high abrasion resistance in industrial applications. In crushed form, basalt also finds use as aggregate in concrete.

More recently, continuous fibers extruded from naturally fire-resistant basalt have been investigated as a replacement for asbestos fibers, in almost all of its applications. In the last decade, basalt has emerged as a contender in the fiber reinforcement of composites. Proponents of this late-comer claim their products offer performance similar to S-2 glass fibers at a price point between S-2 glass and E-glass, and may offer manufacturers a less-expensive alternative to carbon fiber for products in which the latter represents over-engineering.

Image result for basalt fibres as reinforcement for composites

 

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7 minutes ago, SF Woody Sailor said:

That makes perfect sense, thanks!

I think UHMPE makes more sense. The whole point is to prevent damaging the laminate.

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On 13.7.2017 at 11:38 PM, fastyacht said:

If you want to know kevlar 49 properties just look them up.
http://www.dupont.com/content/dam/dupont/products-and-services/fabrics-fibers-and-nonwovens/fibers/documents/Kevlar_Technical_Guide.pdf

Note that kevlar patent ran out years ago and Twaron and other Japanese fibers are used instead, in many applications. DuPont dropped out of the sailcloth business for instance.

And that and many other sources gives density as 1440 kg/m3, or 1.44 g/cm3 or 0.052 lb/in3.

Most epoxy is less dense at 1100...1200 kg/m3, thus kevlar does not float in epoxy when wet out properly, but does that when not.

I never had any problems in practice with floating when I was working with it in epoxy.

Polyester is significantly more dense than epoxy and kevlar can float in that matrix.

 

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2 hours ago, Rasputin22 said:

I've been looking at a fairly new (to me) fiber cloth for composites made of Basalt. Sound a lot like what we used to call 'Rock Wool' but is available in woven form now. I get the impression that it can replace E-Glass and provide much better abrasion resistance. I'll post what I can find.

A hard, dense volcanic rock that can be found in most countries across the globe, basalt is an igneous rock, which means it began in a molten state. For many years, basalt has been used in casting processes to make tiles and slabs for architectural applications. Additionally, cast basalt liners for steel tubing exhibit very high abrasion resistance in industrial applications. In crushed form, basalt also finds use as aggregate in concrete.

More recently, continuous fibers extruded from naturally fire-resistant basalt have been investigated as a replacement for asbestos fibers, in almost all of its applications. In the last decade, basalt has emerged as a contender in the fiber reinforcement of composites. Proponents of this late-comer claim their products offer performance similar to S-2 glass fibers at a price point between S-2 glass and E-glass, and may offer manufacturers a less-expensive alternative to carbon fiber for products in which the latter represents over-engineering.

Image result for basalt fibres as reinforcement for composites

 

Could it be used as the mortar in a ferro boat? :D

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They have made/sold Basalt Re-Bar  ( the steel rods that go into reinforced concrete )  - and,  since they stuff doesn't rust,  which is a major cause of concrete failure - there would seem to be some justification.

Boatcat,  there is a good reason that old race-horses like that get sold off for pennies on the dollar,  and that us because re-fitting them isn't cost-feasible  (what it would cost to do the work could acquire a better boat) and when you DO get them safe to sail again they are STILL old race boats,  and most of those just aren't very comfortable/well-suited to short-handed cruising.

If you have your heart set on it,  AND you want a club-racer and coastal fast cruiser,  have the budget to renovate AND like to do extensive boat projects rather than go sailing,  then yeah - it's right up your alley.   It's just that a lot of race-crews have the loyalty of crack-whores  (and I say this out of all respect to whores) so don't expect the young turks to provide crew for you when there is a host of newer, better, faster, cooler boats to choose from.

There are a BUNCH of older race-boats in this 40-foot ish size range that could be a lot of fun if they had a rig that could be trusted to stay aloft,  but as they are...well - it's kinda like handling old ammunition.  I mean....it's PROBABLY safe,  but... and it's sad - because if there WERE an easy donor-rig that could be plugged in - like a nice clean J-35 mast,  just for example - that'd be PLENTY of sail area for cruising - but what does one of those go for ?  and just how much of a Franken-boat do you have once it is fitted ?  What does the new standing rigging cost ?  Now, you'll want some sails....  see why these aren't sold already now ?

 

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Just now, Great Red Shark said:

They have made/sold Basalt Re-Bar  ( the steel rods that go into reinforced concrete )  for a dozen years now - and,  since they stuff doesn't rust,  which is a major cause of concrete failure - there would seem to be some justification ( surprise,  it's more expensive than steel re-bar )

Boatcat,  there is a good reason that old race-horses like that get sold off for pennies on the dollar,  and that us because re-fitting them isn't cost-feasible  (what it would cost to do the work could acquire a better boat) and when you DO get them safe to sail again they are STILL old race boats,  and most of those just aren't very comfortable/well-suited to short-handed cruising.

If you have your heart set on it,  AND you want a club-racer and coastal fast cruiser,  have the budget to renovate AND like to do extensive boat projects rather than go sailing,  then yeah - it's right up your alley.   It's just that a lot of race-crews have the loyalty of crack-whores  (and I say this out of all respect to whores) so don't expect the young turks to provide crew for you when there is a host of newer, better, faster, cooler boats to choose from.

There are a BUNCH of older race-boats in this 40-foot ish size range that could be a lot of fun if they had a rig that could be trusted to stay aloft,  but as they are...well - it's kinda like handling old ammunition.  I mean....it's PROBABLY safe,  but... and it's sad - because if there WERE an easy donor-rig that could be plugged in - like a nice clean J-35 mast,  just for example - that'd be PLENTY of sail area for cruising - but what does one of those go for ?  and just how much of a Franken-boat do you have once it is fitted ?  What does the new standing rigging cost ?  Now, you'll want some sails....  see why these aren't sold already now ?

 

 

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39 minutes ago, Great Red Shark said:

They have made/sold Basalt Re-Bar  ( the steel rods that go into reinforced concrete )  - and,  since they stuff doesn't rust,  which is a major cause of concrete failure - there would seem to be some justification.

Boatcat,  there is a good reason that old race-horses like that get sold off for pennies on the dollar,  and that us because re-fitting them isn't cost-feasible  (what it would cost to do the work could acquire a better boat) and when you DO get them safe to sail again they are STILL old race boats,  and most of those just aren't very comfortable/well-suited to short-handed cruising.

If you have your heart set on it,  AND you want a club-racer and coastal fast cruiser,  have the budget to renovate AND like to do extensive boat projects rather than go sailing,  then yeah - it's right up your alley.   It's just that a lot of race-crews have the loyalty of crack-whores  (and I say this out of all respect to whores) so don't expect the young turks to provide crew for you when there is a host of newer, better, faster, cooler boats to choose from.

There are a BUNCH of older race-boats in this 40-foot ish size range that could be a lot of fun if they had a rig that could be trusted to stay aloft,  but as they are...well - it's kinda like handling old ammunition.  I mean....it's PROBABLY safe,  but... and it's sad - because if there WERE an easy donor-rig that could be plugged in - like a nice clean J-35 mast,  just for example - that'd be PLENTY of sail area for cruising - but what does one of those go for ?  and just how much of a Franken-boat do you have once it is fitted ?  What does the new standing rigging cost ?  Now, you'll want some sails....  see why these aren't sold already now ?

 

But as you have hinted at, we get into the philosophical discussion. Indeed, even DORADE was a race boat. Restoring her took huge effort. On the classic yacht circuit, there is a staggering amount of restoration effort. But people enjoy it. And as you say, if that's up your alley, then it is a good thing!

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8 minutes ago, fastyacht said:

Even DORADE was a race boat. Restoring her took huge effort. On the classic yacht circuit, there is a staggering amount of restoration effort. But people enjoy it. And as you say, if that's up your alley, then it is a good thing!

+1

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BTW having sailed on the course with DORADE and then (not realizing it because she was simply a beautuiful yawl in the distance during the race) sailing to our mooring *right next to her* --- oh my God! I was in serious wooden boat insane blissful disbelief. DORADE!   THE DORADE!  So incredibly perfect. With Onne Van der Wal lighting too :-)

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23 minutes ago, fastyacht said:

BTW having sailed on the course with DORADE and then (not realizing it because she was simply a beautuiful yawl in the distance during the race) sailing to our mooring *right next to her* --- oh my God! I was in serious wooden boat insane blissful disbelief. DORADE!   THE DORADE!  So incredibly perfect. With Onne Van der Wal lighting too :-)

Since we are on the (completely tangential) topic of Dorade, here is a funny anecdote. I was having dinner at the YC with my boys (ages 6 and 10) one evening when I saw Mr. Brooks and Mrs. Levy dining at an adjacent table. I took the kids over to introduce them, and explained that this couple owns the most famous sailboat in the world and has done the entire yachting world and the heritage of our sport a tremendous service by not only restoring her to concours d'elegance condition but by having the temerity to go out and re-conquer all of the planet's most important yacht races. They exchanged pleasantries, and that was the last I thought of it.

A couple of weeks later a package arrived unexpectedly in my office. It contained two youth size Dorade hats, two Dorade belts, and two youth size Dorade polo shirts together with a note from Mr. Brooks saying that it was a pleasure to meet two well behaved young gentlemen. How amazingly thoughtful is that!!! 

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Nice!
Another anecdote.
A long time ago. 1993 I think, or maybe later summer 1992. I spent an entire day with Myron Spaulding in his shop. Along with all the stuff I learned that day was that during the war, he was caretaker of DORADE. At one point, he sailed her all the way from Seattle or Portland (can't remember for sure which) to Tiburon (or vice versa). He had to get special permission from the War Department--after all, there was a war going on!

(I had lunch with Gary Mull on that same trip--who of course also knew Myron very well. Unfortunately we lost Gary a few months later. I had no idea he was suffering from cancer. I was glad to have met him and really enjoyed listening to him. He had become an expert at composite engineering and was responsible for sorting out a lot of production boatbuilders from otherwise disastrous structural arrangements.)

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I'd start shopping around for a Concordia 47. It's basically everything you want, but already done. 

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32 minutes ago, fastyacht said:

Nice!
Another anecdote.
A long time ago. 1993 I think, or maybe later summer 1992. I spent an entire day with Myron Spaulding in his shop. Along with all the stuff I learned that day was that during the war, he was caretaker of DORADE. At one point, he sailed her all the way from Seattle or Portland (can't remember for sure which) to Tiburon (or vice versa). He had to get special permission from the War Department--after all, there was a war going on!
 

Myron was a gem: a treasure trove of stories as well as a supremely talented craftsman. The wooden boat center here in Sausalito is named after him http://www.spauldingcenter.org/

 

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Most of the production Laser 28's were in Kevlar/Epoxy but later ones were e glass. They seem to be holding up OK but some had keel wobble issues after the grid separates.(usually do to hitting something) Why did they choose Kevlar instead of cheaper glass? It's an open interior with no bulkheads or ring frames for loads but has beefy box section stringers and ribs. Does that require a stiffer structure? I think they used vacuum/injection layup and originally tried to do a new process called closed molding but it didn't work.

 

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Probably a Corel 45 would be a better choice, given the OP's statements about performance v simplicity.  But the base purchase is about 3 times what he is looking to pay for Javelin.  

With regards to Kevlar v Glass, definitely working with Kevlar was trouble.  No more so than working with other high performance structures of the time (honeycomb anyone?).  It holds up well enough to cycling loads, but even at the time when that boat was built, there were better solutions that were used (S-Glass).  

 

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Learning that basalt is the newest structural component has made my day!  The idea of glass being woven into a structural material is mind boggling enough when you think about it.  But basalt rock- now that takes it to the next level of strange.  And the performance is superior to boot!  As somebody who grew up in Spokane, Washington- where basalt is the prominent geographic feature, it's even better.

Here's an example of a race oriented day sailor/cruiser that fits the budget and general criteria- just wish it was 10 feet longer:

http://sailnorthwest.com/boat/farr-39/

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13 hours ago, Rasputin22 said:

I've been looking at a fairly new (to me) fiber cloth for composites made of Basalt. Sound a lot like what we used to call 'Rock Wool' but is available in woven form now. I get the impression that it can replace E-Glass and provide much better abrasion resistance. I'll post what I can find.

A hard, dense volcanic rock that can be found in most countries across the globe, basalt is an igneous rock, which means it began in a molten state. For many years, basalt has been used in casting processes to make tiles and slabs for architectural applications. Additionally, cast basalt liners for steel tubing exhibit very high abrasion resistance in industrial applications. In crushed form, basalt also finds use as aggregate in concrete.

More recently, continuous fibers extruded from naturally fire-resistant basalt have been investigated as a replacement for asbestos fibers, in almost all of its applications. In the last decade, basalt has emerged as a contender in the fiber reinforcement of composites. Proponents of this late-comer claim their products offer performance similar to S-2 glass fibers at a price point between S-2 glass and E-glass, and may offer manufacturers a less-expensive alternative to carbon fiber for products in which the latter represents over-engineering.

Image result for basalt fibres as reinforcement for composites

 

It has been around a while.  Here is an article on the history of it's development that was published over a decade ago: http://www.compositesworld.com/articles/basalt-fibers-alternative-to-glass 

Sounds like the US plastics companies stopped research on it in the 70's focusing more on polyester which lead to the development of things like S-2 glass.

I suppose it could be a viable alternative to E-Glass if they can get the price down.to a similar level.

But for now, it looks like it is more of an alternative to S glass, which there doesn't seem to be much demand for except in certain smaller applications.  When was the last time an S-2 glass hull was built?  Much easier for most retail customers to source even CF today than S-2, which to me gives a pretty good idea of the demand (or lack thereof) for S-2.

It would be great if it basalt fiber could be made viable, but for now I suspect demand would be limited.

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The primary reason that carbon trumped s2 isn't strength but specific stiffness. Most of the weight of structures is stiffness driven. Carbon's specific stiffness is tops. Heck Kevlar is great stuff but even carbon beats it on specific stiffness. Only engineering metals beat carbon on an economic basis (Al, Ti, Fe). And the aerospace carbons are even higher stiffness (but ridiculously expensive and not as strong as E glass).

Just using the DuPont Kevlar data document I linked, we get the following specific stiffnesses. Note that this is for the fibers themselves, not the composite....therefore steel actually looks far better than it appears here in practice....in other words my third column. If you make a carbon part out of tooling cloth, wet preg, vacuum bagged, your part will be about 20% stiffer or 20% lighter than a comparable metal part--assuming geometry issues do not come into play (which they usually do!--which favours composites over metals for less concentrated loading). Where you can use Unidirectional to advantage, you dramatically improve on metal (masts etc).

Material                  Specific Stiffness                    approx specifi stiff in biax woven at ~50% volume ratio to resin
E glass                        114                                      29

S glass                         138                                    35

Kevlar 29                      196                                     49
Kevlar 49                     313                                       78

Steel                            103                                     103

"Hi tenacity Carbon"         492                                   123
Note that carbon comes in many forms. "hi tenacity" is strong but not so stiff carbon--in other words tooling cloth etc---what boats are made of. The high stiffness aerospace pitch based carbon is more than triple this figure

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