Carbon Fiber vs. Wooden Oars
Charles Carroll
the Sedna, and try to cross the Pacific. The New York Times' Sunday
Supplement, "Play" (June 2007, p.16), calls this the "long paddle westward."
Most of you are probably aware that Ms. Savage has already completed a
Trans-Atlantic paddle.
Now here is a very interesting quotation from this article. The subject is
what Ms. Savage learned from the Tran-Atlantic paddle and will do
differently on the "long paddle westward."
"Eighty-three days on the Atlantic ... [taught Roz Savage] important
lessons: pack wooden oars (by Day 48, each of her four carbon fiber oars was
being held together by duct tape) ."
Is Roz Savage doing a prudent thing trading in her carbon fiber oars for
wooden ones? Are wooden oars more durable?
Yesterday I put this question to David Lay, a friend I scull with. In David'
s opinion carbon fiber oars are every bit as durable as wooden oars. The
problem, he thinks, can be blamed on exposure to UV light.
Then, surprisingly, David thanked me for having brought this problem to his
attention. He said that until this moment it had never occurred to him to
coat his carbon fiber oars with sunscreen. But now that he had heard of Ms.
Savage's problems with her carbon fiber oars, this is what he was going to
start doing.
Is David coming up with a brilliant, if eccentric, solution to the effect of
exposure to UV light on carbon fiber oars? Or is he just pulling my leg?
All comments welcome.
Chris Kerr
UV damage is certainly a problem for a lot of plastics, but coating them is
sunscreen isn't going to help - anything that isn't stuck on or bonded into
the resin of the shaft will just wash off. I expect painting the shafts of
the oars would work.
I would have expected, however, that oar manufacturers would already use UV
absorbing additives in their resins to safeguard against this problem.
Alistair
I'd be cautious about using sunscreen - back when I was a climber we
were warned to take care to keep sun cream away from your ropes as it
could weaken them...
mpruscoe
> Is Roz Savage doing a prudent thing trading in her carbon fiber oars for
> wooden ones? Are wooden oars more durable?
>
> Yesterday I put this question to David Lay, a friend I scull with. In David'
> s opinion carbon fiber oars are every bit as durable as wooden oars. The
> problem, he thinks, can be blamed on exposure to UV light.
>
> Then, surprisingly, David thanked me for having brought this problem to his
> attention. He said that until this moment it had never occurred to him to
> coat his carbon fiber oars with sunscreen. But now that he had heard of Ms.
> Savage's problems with her carbon fiber oars, this is what he was going to
> start doing.
>
> Is David coming up with a brilliant, if eccentric, solution to the effect of
> exposure to UV light on carbon fiber oars? Or is he just pulling my leg?
>
> All comments welcome.
>
>
Doing a quick search for her blog from the atlantic crossing, some of
the breakages were spoons snapping off, and one photo looks like a shaft
buckled and bent when it was trapped against and bent around part of the
hull. The oars are getting loaded in ways that aren't usually
encountered in normal rowing, and maybe wooden oars will stand up to
that treatment a bit better.
Charles Carroll
> buckled and bent when it was trapped against and bent around part of the
> hull. The oars are getting loaded in ways that aren't usually
> encountered in normal rowing, and maybe wooden oars will stand up to
> that treatment a bit better.
Mark,
I, too, was wondering if the alleged fragility of the carbon fiber sculls
might have something to do with the special demands Ms. Savage is putting on
them. But then I started looking at some of the scullers in the Sausalito
Club and how their oars were holding up.
I guess I will have to use David Lay as a primary example again. He rowed
six thousand miles last year. This is a lot of rowing. But David's retired,
and hangs out at the Club all morning, and frequently goes out three
separate times in a day. I mention David because all his rowing appears to
be wearing out his beautiful, almost brand new carbon fiber sculls. The
blades have come loose from the shafts and are twisting. He has had to epoxy
them back into place. The shafts themselves appear to have lost some of
their stiffness. (Oh God! That's an opening if ever I saw one.)
In any event, silly me! I somehow was under the impression that a Pair of
well-made carbon fiber sculls should last a little longer than eighteen
months. David claims that his sculls in particular are wearing out because
he leaves them at the dock between outings. The UV light, he says, is
playing havoc with his sculls. The same thing, he thinks, might be happening
to Roz Savage's sculls. The sculls are exposed to intense UV light all day
long, and this exposure is accelerating the aging process of these sculls.
Think of normal usage. Sculls are exposed to the sun 60 to 90 minutes 2 to 5
times a week, and otherwise live on a rack protected from the sun.
Last point. We found several cans of wax in the boat house and they all
contain some sort of sun block. David is just going to trying waxing his
sculls. I have never heard of anyone's doing this, and neither has he. But
if it prolongs the serviceability of his sculls, why not?
Cordially,
Charles
Jonny
something that is often black in colour!
The older C2 oars were often accused of 'un-winding' with age and
altering the pitch.
Croker oars have a number of different shaft types available and the
highest end ones are for Olympic level flat water racing. The company
recommends that clubs and schools buy the next level down (slightly
heavier, more durable to knocks, cheaper). If I were ocean rowing I
would get the next leve below that!
edward...@googlemail.com
wrote:
> Is David coming up with a brilliant, if eccentric, solution to the effect of
> exposure to UV light on carbon fiber oars? Or is he just pulling my leg?
Sailors, for one, have known of the dangers of UV on epoxy/carbon
fibre for a while. Nowdays, all carbon spars - masts etc - are given a
coat of either UV inhibiting clear coat or paint, before leaving the
building shop. Very surprised to hear that blade makers don't do the
same.
Dave Sill
>
> Last point. We found several cans of wax in the boat house and they all
> contain some sort of sun block. David is just going to trying waxing his
> sculls. I have never heard of anyone's doing this, and neither has he. But
> if it prolongs the serviceability of his sculls, why not?
Here's a product that seems to be designed for UV-protecting things like
boats. They specifically mention carbon fiber composites.
http://www.303products.com/tech/index.cfm?fuseaction=product.display&Product_ID=428&CFID=3563599&CFTOKEN=68226368
or http://preview.tinyurl.com/2vlksc
I'm not affiliated with the manufacturer and haven't tested their UV
protection claims, but I have used it in/on my cars as a non-slimy
alternative to Armor-All. Spraying and wiping it on a boat/oars
regularly would be easier than waxing, IMHO.
--
Dave Sill
Jonny
Masts on yachts spend all day, every day in the sun. Oars are usually
only out in the sun during a training session (a couple of hours a day
max) and not always in the peak uv zone for the day. Perhaps it has
never been seen as a complete necessity?
donal...@gmail.com
protector for the paint and then 2 part clear lacquer.
I wouldnt have thought though that blades would be 2 pac lacquered in
this way.
Is it really the UV - carbon on blades is good for strength in certain
directions and was loads better in clashes than wooden
blades..nevertheless it still has a reputation for being brittle and
there is a lot of xxxp out on the oceans. Also of course there is the
salt water to contend with.
Donal
Charles Carroll
> directions and was loads better in clashes than wooden
> blades
Hi Donal,
This is the other point that provokes my curiosity. Why would Roz Savage
think that wood would be any better than carbon? It is astonishing that the
carbon oars lasted only 43 days. But what makes her think wood would be any
more durable?
Cordially,
Charles
Mike Sullivan
"Jonny" <jonny.c...@gmail.com> wrote in message
news:1181138267.0...@z28g2000prd.googlegroups.com...
> On Jun 6, 7:41 pm, edward.fr...@googlemail.com wrote:
>> On Jun 5, 6:25 pm, "Charles Carroll" <charles_carr...@comcast.net>
> Masts on yachts spend all day, every day in the sun. Oars are usually
> only out in the sun during a training session (a couple of hours a day
> max) and not always in the peak uv zone for the day. Perhaps it has
> never been seen as a complete necessity?
I have sculls outdoor in the sun at the Clear Lake club. I protect
them with a varnish wash every year. Just thin varnish with some
thinner and spread it on with a big brush.
The failure spots for old CII oars I usually see is where wood
handles insert into the carbon fiber tubes. The wood stays
wet from water getting inside and never properly draining,
it rots and breaks off.
Seen it happen to the aluminum handles at the salt water
location, cuts off clean like it was hacksawed right at
the edge.
Walter Martindale
impacts with the bottom of the hull or something. When scullers in
racing shells (not the ocean boats) lose their grip on the blade, be it
wood or carbon, the blade can get dragged under the rigger and snapped.
It's not that common but I've seen a few.
Walter
Carl
May I turn your question around on itself, Charles, by asking why you
might suppose that wood would not outlast carbon?
What we know about carbon is that it has very high elastic modulus
(resistance to extension or compression but fairly low strain energy to
failure. It is also almost 3x as dense as wood.
You can make oars from carbon which are, for equal stiffness and similar
cross-section, about 2/3 the weight of a wooden oar. But the carbon oar
has then to be a thin-walled tube whereas the wooden oar is either
thick-walled or solid. Apply a side-load (crushing load) to a
thin-walled tube & it relatively easily goes out of shape (buckles). As
it thus locally flattens or indents, the local bending stiffness in that
direction drops off dramatically. If it is simultaneously subject to
such bending loads, they tend to increase the degree of buckling. Even
if you do not already have severe fibre fracturing (because carbon has a
very low ultimate strain (extension) before failure, you will then get a
catastrophic failure as, contrary to the normal bending process where
resistance to deformation increases with degree of bend, in a buckling
failure the resistance drops as the bend increases - a 1-way path to
fracture.
We use carbon oars for racing precisely because they can be made light
(& easily), & because we know within narrow limits the range of stresses
& load conditions they will encounter. When you hit an immovable
object, however, a carbon oar is much more prone to complete fracture
than its wooden counterpart. And it is impossible to repair. So if you
are slogging against unpredictable forces, a lightweight racing oar has
too low a safety margin & you should either opt for thicker-walled
carbon, or glass (which although denser is more forgiving), or a
filled-core tube (better crush resistance,) or wood (which has better
repairability & more forgiving physical characteristics).
Blade/loom joint failures can arise from a number of causes, including
poor joint design (insufficient bondable surface area or length of
insertion), poor preparation before bonding (laminated surfaces need
good scouring if they are to bond well), inadequately wetted bonding
surfaces (poor workmanship, & you should always apply resin to both
surfaces), air pockets trapped in the bond line, inaccurate resin mix or
too long between resin application & joint closure.
Finally to UV: yes, UV slowly degrades all organic materials (resins
are a product of organic chemistry), impairing their internal chemical
bonds & structure. The only preventative is to use resins of known UV
resistance or to apply UV-filtering coatings.
--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing low-drag Riggers/Advanced Accessories
Write: The Boathouse, Timsway, Chertsey Lane, Staines TW18 3JY, UK
Email: ca...@carldouglas.co.uk Tel: +44(0)1784-456344 Fax: -466550
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)
Stamps
wrote:
> impacts with the bottom of the hull or something. When scullers in
> racing shells (not the ocean boats) lose their grip on the blade, be it
> wood or carbon, the blade can get dragged under the rigger and snapped.
> It's not that common but I've seen a few.
Yes, easily done - happened to us a few weeks ago. We use Croker
sculls, and the grips get pretty slippery here - very hot and humid so
sweaty hands, the only way to keep your grip in the conditions is to
dip your hands in the sparkling azure waters of the Shing Mun River
every time you stop. And part of that sentence is true.
My doubles partner recently clipped a wave and dropped one of his
sculls, and, as the boat was moving extremely fast I might add, it
looped round out of reach, got caught under the rigger and snapped
off. Useful in the end as we had a friend leaving Hong Kong so could
get Jonny to paint the blade up as a leaving gift.
I've also seen at least 1 person throw the oar away from themselves in
disgust after a bad piece, then look like a real muppet as they watch
the expensive equipment get caught under their rigger and snap.
Stamps