Carbon fiber in boat building?

Discussion in 'Boatbuilding' started by Andrus, Dec 4, 2010.

  1. CatBuilder

    CatBuilder Previous Member

    It sure is sad. I think he'll reinvent himself well in the turbine blade market, or possibly he is just diversifying and will start back into the boats (running both) when the market for his type of boats recovers. They both use all the same technology and equipment.

    IMO (having owned a few businesses), it looked like too much investment in the building/plant just before a severe downturn in his market. Double whammy. But hey, that's running companies for you. I've had a couple fail due to rapidly changing markets and not being paid a massive receivable.

    You just carry on... like he's doing with the wind stuff for now.
     
  2. carbon fiber
    Joined: Dec 2010
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    carbon fiber New Member

  3. Stumble
    Joined: Oct 2008
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    Stumble Senior Member

    Carbon,

    I know that a lot of boats use CF. I own a sailboat with it all over the place, and two powerboats with it as well. But the reality is that to make an entire boat out of CF is prohibatively expensive compared to high quality glass. It just isn't accessable to the average consumer to buy a boat made entirely from it. When it becomes price competative then who knows.

    What is becoming common is for highly stressed, highly loaded components to be made out of CF. Sailboat masts, Spinnaker poles, booms, even some internal support structures, but outside of the boats owned by billionaires I don't know of a single large sailboat made from CF entirely. And on those boats... well the Andrews 70 I raced on also used titanium forks, and required everyone to show up wearing underwear then change into team provided gear every race to keep weight down too.
     
  4. Herman
    Joined: Oct 2004
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    Herman Senior Member

    Stumble: What is large? I know of at least a couple of 48 ft boats, and a 64 ft boat completely out of carbon fiber. (cruising boats, that is). But indeed, I do not see the benefits, over a well engineered glass boat.

    Of course VOR and AC boats are all carbon fiber, as are many other racing boats.

    To "carbon fiber". Nice website. Is it yours?
     
  5. mark775

    mark775 Guest

    Stumble, allow a bit of conjecture here, please: Let's say, for example, that a core is out of the question (It's a hull in question, and the Coast Guard won't give a go on beneath the waterline core, or you simply don't want a core down there). I won't pretend to yet know how much CF one would need to resist damage at speed by a large, vertical piece of timber, but whatever that thickness is, to me, it is the maximum necessary as suredly, by that point, the boat form is stiff enough and able to withstand the different loads introduced by the sea itself. Not so with glass! I have been in compartments of glass boats and seen the flexion between stiffeners, bulkheads, webframes, stringers. I realize also that placement of the stiffeners is part of the designer's job and a good design will not allow flex in an manner that will cause damage but time has told, IMO, that boats are often overbuilt in some areas yet lacking in others. We can improve upon that through better design, of course, but might we not also improve through use of a stiffer material? My point is (and I'm not trying to write a dissertation here. sorry) that maybe the Pro boatbuilder article didn't quite cover it or the author didn't interview the correct people. What if there were one major builder that would have said, "You know, we might get a stiffer structure and be able to eliminate two plys of 3208 if we substitute one mm of CF. We didn't need all that for impact resistance but only put those extra drums of resin in the glass hull matrix for stiffness. Also, perhaps we should be analizing use of carbon in many areas previously overlooked, afterall, fuel is not getting any cheaper!"
    From a different perspective, assume that the fuel curve is not linear, i.e., that a 5% reduction in total vessel weight doesn't gain 5% in fuel savings but that with a given set of build parameters (This engine, that transmission, carrying this much cargo), the thing is 3% short of getting on top of the planing hump and there is a 30% reduction in fuel use when achieving that - it may take a much shorter interval to recover the increased build material cost in this scenario. I burned, I don't know, in the neighborhood of $26,000 in fuel this year. If I could get to that next tidal current a few times by being just a bit faster, I might cut a bit off that. If I put another passenger on but then can't quite get on step so end up losing money on that incremental passenger, I'd be wishing I had somehow shaved 200 lbs. off the build weight. I'm not schooled in design and maybe I'm full of it but I just don't believe we've given CF as close of look as we could. I can feel a little extra weight on my boat - I know every cooler of beer and fat man slows me down. At $.78 fuel I carried a spare case of bleach. At $4.15, I carry just enough aspirin for today!
     
  6. Stumble
    Joined: Oct 2008
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    Stumble Senior Member

    Herman,

    I mispoke a tad. By large I was really thinking in terms of budget, though normally over 65'. Of course there are some racing classes under that size that use all carbon boats, and the TP 52' for instance is a CF boat. But again these boats new top out in the millions of dollars, and despite their billing as racer/cruisers they are really racing machines that can be slept on.

    I am certainly willing to accept that there are a few true carbon fiber cruisers out there, but I can only imagine they are custom built. I for one have not seen a single manufacturer making an all carbon fiber boat, though a lot of the performance cruisers (Like Alan Andrews, and Santa Cruize Yachts) are using CF to reinforce E-Glass constructions. The reality is outside of sponsored racing the cost to benefit is just not worth it.

    I would note that the use of CF in certain critical applications like masts, spinnaker poles, rudders, and rudder stocks though may be a good idea even given the additional cost. A mast for instance may save thousands of pounds of righting moment by switching to CF over an aluminium extrusion, at a price that while more is at least acceptable. CF spinnaker poles are both lighter, and much easier to move around, making them worth the additional price, particularly for short handed crews. And Rudders/rudder stocks add a lot to the feel of the boat, and are much stiffer than the alternatives making driving more precise. Plus you reduce weight in the ends which is always a good thing.
     
  7. War Whoop
    Joined: Jun 2003
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    War Whoop Senior Member

    I would only use CF to a small percentage with "S" Glass,CF's problem is it has a very small elongation then catastrophic failure.
     
  8. anthony goodson
    Joined: Mar 2007
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    anthony goodson Senior Member

    CF doesn't react well to sharp impact,virtually no deformation before failure.Just watch an F1 racecar crash ,small shards all over the track.Local firm making replica bodies has gone back to GRP and Kevlar for nosecones.
     
  9. Stumble
    Joined: Oct 2008
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    Stumble Senior Member

    Mark,

    You were posting as I typed so sorry I missed it.

    You are correct that CF is much more stiff than Fiberglass, and so you need less material thickness to get the same stiffness. Though in practice on boats what this really means is that you need a thicker core, and thinner walls since even the extra stiffness of CF can't make up much for the squaring of stiffness with thickness.

    Combine this with the fact that CF is terrible at abrasion resistance, which almost requires a Kevlar skin be placed around the boat. This adds little to stiffness, but a lot to cost, as well as adding weight that the FG doesn't need.

    All of these are surmountable problems, but the question is how much does it cost compared to how much does it save in weight. I actually have been unable to find an all CF boat that even hass a close corrilary in glass, so I can't tell you for sure. But the best examples I have seen (CF vs Glass car hoods, yes it is a terrible example, but it all I could find), indicates something like a 50% decrease in the weight of the structure for a price increase of between 700 and 1,000%. Now boats have a lot more non hull weight than a hood, so I think those numbers would probably look more like a 20% decrease in weight for a 500% increase in cost, though I could be off on those numbers wildly.

    Again I just can't see how this could ever result in an economic benefit from fuel use. The up front expense is just too high to ever be paid for from fuel alone.
     
  10. mark775

    mark775 Guest


  11. carbon fiber
    Joined: Dec 2010
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    carbon fiber New Member

    @ Stumble: i admired you sir, you are very wealthy and famous who owns a CF boat.
    @ Herman: Thanks for the compliment, Yes the site is mine selling a lot of types of carbon fiber tubes. I plan to sell composite materials too. Let me know if you want to buy, Thank you very much!
     
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