Carbon Fiber Boats

[haulnazz15]

So when do you think we'll see the advent of mass production boats made from Carbon Fiber/Composites instead of the fiberglass common to today? I dunno why it popped into my head, but it seems like you could make a solid/lightweight boat out of carbon fiber just as easily as you can with fiberglass. I don't know that it would really be much lighter than fiberglass though.

Anybody know and pros/cons to the idea? I know cost would likely be a factor as CF isn't cheap.

 

[180Fisherman]

Re: Carbon Fiber Boats

Making and working with carbon fiber is very labor intensive hence the expense. Maybe they could do it in China. But then who'd buy it?

BTW, why didn't kevlar ever become more widely used?

 

[haulnazz15]

Re: Carbon Fiber Boats

I'm also not sure how impact-resistant CF is compared with fiberglass, so that may be a downside as well. Kevlar is use in a lot of boat applications. Cobalt uses Kevlar interlaces hulls and keels to improve strength at high-load points.

 

[salty87]

Re: Carbon Fiber Boats

BTW, why didn't kevlar ever become more widely used?

my hull has kevlar in it, from 1987....supra tournament inboard. i think they used kevlar starting in 83 maybe

 

[jkust]

Re: Carbon Fiber Boats

Cobalt uses Kevlar interlaces hulls and keels to improve strength at high-load points.

Looks like some Chaparrals use Kevlar also. Not sure if mine has it though.

 

[fixb52s]

Re: Carbon Fiber Boats

Kevlar cloth really doesn't make the structure much better than regular glass. More of a marketing ploy.

As for Carbon Fiber, it is indeed difficult and expensive to use. The hull would have to go into an autoclave to cure it. (The autoclave heats the part and vaccums the air out). Repair work would be extemery difficult to do. With that said, some racing hulls are made from it, and it is indeed ligher and handles the forces that beat it up due to 160+ speeds on the water.​

 

[45Auto]

Re: Carbon Fiber Boats

5.8 oz per square yard x 50" carbon fiber is $23/yard.

5.1 oz per square yard x 50" kevlar is $16/yard.

5.6 oz per square yard x 50" fiberglass is $4/yard.

Material for a carbon fiber hull would cost about 6 times as much as a fiberglass hull. Only benefit is that it would weigh less, so it would maybe be 2 or 3 MPH faster.

Cost is a much more powerful selling point than a couple of MPH in top speed unless you're shopping for a racing boat. There's easily several hundred yards of material in a typical 18'-20' runabout, so the material cost for the carbon fiber would be $4000 - $5000 higher. Given a choice between 2 identical boats, one that was a couple of MPH faster and one that cost $5000 less, my guess is that 99 percent of the new boat shoppers would go for the cheaper boat. The boat builders have probably figured out the same thing .....

 

[arks]

Re: Carbon Fiber Boats

Canoes and kayaks are boats.
Carbon Fiber (and other composites like kevlar) are used for their hulls but, as mentioned, the price goes way up. The primary benefit is lighter weight, usually 10-15% less than an identical fiberglass model.


Here's a little blurb I copied from a kayak buyers guide. IMO it answers the reasons why CF and kevlar aren't used much for production boat hulls :

Fiberglass
Fiberglass kayaks can either have thin, lightweight hulls, or thick, tough, heavy hulls, depending on their anticipated use. Glass kayaks are susceptible to damage from dropping or dragging, so treat your glass boat with care. Gelcoat will absorb most minor damage without causing structural harm. These kayaks are easy to repair with fresh resin and glass, provided the damage isn't too extensive.

Glass kayaks cost from $1,000 to $2,500.

Carbon Fiber
Carbon fiber kayaks are extremely stiff, lightweight, beautiful, brittle, and expensive. Carbon fiber isn't used extensively in sea kayaks, but is often used in finer racing and Olympic boats.

Carbon fiber kayaks are constructed with the same resins and methods as fiberglass kayaks. Carbon fiber is extremely stiff.

This results in a very stiff kayak that doesn't require much hull thickness. This stiffness also results in a brittle kayak that should be treated gingerly. Like fiberglass kayaks, carbon fiber kayaks can repaired quite easily, but the carbon fiber fabric for the repair will cost more.

CF boats often cost $2,000-4,000.

Kevlar
Thanks to the US space program, we have Kevlar as a kayak building material. Kevlar kayaks are stiff, lightweight, yet extremely tough, and expensive.

Kevlar is the stuff bulletproof vests and flak jackets are made of. Kevlar is slightly less stiff than fiberglass, but much tougher and lighter weight. Kevlar kayaks are made in the same manner as fiberglass and carbon fiber kayaks. Often, a little fiberglass or carbon fiber will be combined with the Kevlar cloth in a kayak to give a little added stiffness.

Kayaks constructed from kevlar are very, very tough. Because the fiber itself is so flexible, the kayak will absorb a serious impact and spring back. A collision with a rock that would hole a fiberglass or carbon boat might result in only cracked gelcoat on a Kevlar kayak.

Kevlar fibers are very tough, and difficult to sand or cut, so repairs are slightly more difficult than fiberglass.

Kevlar boats cost $2,000-$3,500.

 

[metriccrescentwrench]

Re: Carbon Fiber Boats

Kevlar fibers are very tough, and difficult to sand or cut, so repairs are slightly more difficult than fiberglass.

That's an understatement!!! I've worked with kevlar fabric from time to time and it's a ***** to cut. It dulls shears in no time, and is impossible to sand. You always put a layer of glass on the side that will get sanded, otherwise you end up with a fuzzy mess.

 

[haulnazz15]

Re: Carbon Fiber Boats

All good information. With the proliferation of Carbin Fiber though, I would expect for prices to eventually come down a bit. It may be pheasible in 10 years for companies to start using it, as it may not help much with overall top speed, but getting out of the hole and fuel economy should be better with 10-15% weight reductions.

Note: the hull/cap of the boat doesn't necessarily mean the entire weight of the boat goes down 15%. Engines/upholstery/etc weigh quite a bit, too, and would remain unchaged in weight.

 

[Frank Acampora]

Re: Carbon Fiber Boats

Here in PA they use carbon fiber pre-preg to make power generating windmills. 50 foot wind loaded blades need to be as light as possible and strong enough to resist the wind loads. Pre-preg is resin pre-impregnated fiber, must be stored in a freezer warehouse and only shipped for immediate use. Big PIA but the production efficiency is worth it.