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Farlo
20th July 2011, 03:13 PM
Hi everybody,
The other day my wishbone broke suddenly when I was nicely powered up with 7.8 in some 15 knots. Water was rather flat so no particular shock that I can remember. It is a Nautix aluminium boom that I've been using for about seven years, mostly freeracing with sails bigger than 6. The inner tube (protruding from the head) is cut without signs of previous damage or rust. Can it be just stress and strain? I wonder because I'm relatively light (67 Kg) so I can't load it tremendously. Did any of you experience a similar thing?

BelSkorpio
20th July 2011, 06:42 PM
Me and my son have been breaking alu wishbones like it's going out of style.
Most of the times it's close to the head or the head itself.
I guess that the catapults of my son have something to do with it.
Also after a few years, most of the alu wishbones tend to loose their stiffness.
For me, the wishbone is the biggest consumable.
I don't think I have a wishbone of more than 3 years.
Don't know if the carbon wishbones are better, but for the price of 1 you can buy 3 alu's.

Farlo
20th July 2011, 08:18 PM
OK, I must have been lucky then because it is the first I break in 25 years. I will look for a more robust one, maybe a second hand Nautix carbon as they have very good reputation. Any other brand you can suggest?

Unregistered
20th July 2011, 11:41 PM
OK, I must have been lucky then because it is the first I break in 25 years. I will look for a more robust one, maybe a second hand Nautix carbon as they have very good reputation. Any other brand you can suggest?
from what I understand aluminum booms have 2 durability issue, salt corrosion and metal fatigue,
so sooner or latter they do break under usage and generally cannot be repaired.
Carbon doesn't have either problem, but there could be production defects like dry carbon, epoxy not penetrating all the way thru, etc.. good thing about carbon booms, you can repair them, and repair done
correctly will be better than original, so you can use them indefinitely. I hear good things about Maui sails
booms, North, NP and Chinook have nice carbon booms too. I see carbon boom as an investment,
cost more but over the years it pay off: better, lighter,stiffer, stronger and it lasts.

Farlo
24th July 2011, 03:41 PM
Thank you for the advice. There are a few second hand carbon booms in my shop. There is also a Nautix NXtrem with alumin tubes in the front (ergal) and carbon tail. It is the last one as they just discontinued this model in 2011. Have you heard about or tried such combination? I'm afraid it may break because of stiffness difference.

Ken
25th July 2011, 10:27 PM
Aluminum and carbon together oxidize. If it's in the head, it's a really bad idea, but a carbon tail in aluminum tubes? Not sure. The original Gulf Tech booms had a carbon body and aluminum tails, but they also transitioned away to all carbon. I think the stiffness is generally considered to be a boom body issue and not a tail issue, so carbon tails don't sound like a worthwhile idea to me.

In time carbon fatigue will surface. I have had two 100% carbon booms break at the head, but only after several years of use. On the other hand, carbon will most likely last much longer than aluminum.

And if you consider that you could possibly replace your aluminum booms every other year and spend less money than replacing your carbon booms once every 6-8 years, aluminum doesn't sound like a bad idea, especially if you are a fresh water sailor and use the booms on medium to small sails.

Farlo
26th July 2011, 03:46 PM
Thank you Ken, my biggest sail is 7.8 so I'd rather take a good aluminium boom, unless I find a used carbon at the same price but I doubt it. Maybe the difference is not that sensible for lightweight sailors with medium sails.

Unregistered
26th July 2011, 05:48 PM
heard of plenty of masts breaking, but booms ??
i am surprised
my aluminum and carbon booms have never had issues
windsurfing about 15 years, last three(3) shortboarding

if you know your boom is good for 2 seasons, should you just automatically replace it ??
or have a spare??

my concern now is modern sails
people are telling me your most used sails need replacement every 3 to 4 years
on the islands near the tropics i hear they replace them EVERY year
(they often stay rigged all day, etc)

my "modern" sail has seen about 2 full summer seasons and about 40 outings
the monofilm is starting to look grey and the creases sad
the stitching looks bad on one batten to sleeve joint
some people say ride it to the end with some repairs as needed - others say replace it

what say you ??

Jean-Marc
27th July 2011, 01:21 AM
I think the stiffness is generally considered to be a boom body issue and not a tail issue, so carbon tails don't sound like a worthwhile idea to me.

Wrong. A carbon tail inserted into an aluminum boom stiffens up a lot more the entire boom as compared to that with an aluminum tail. The carbon tail does play a key role in boom stiffness.

In time carbon fatigue will surface. I have had two 100% carbon booms break at the head, but only after several years of use. True. My North Sails racing 220-260 carbon boom lasted 5 years before breaking at the junction between the head and the body tubing.

On the other hand, carbon will most likely last much longer than aluminum.

Quite the opposite for me. An all aluminum North Sails boom lasted 15 years before snapping at the junction between the head and the body tubing.

And if you consider that you could possibly replace your aluminum booms every other year and spend less money than replacing your carbon booms once every 6-8 years, aluminum doesn't sound like a bad idea, especially if you are a fresh water sailor and use the booms on medium to small sails.

True for boom less than 2 m long and if you're not a heavy weight racer. Otherwise, a carbon boom is stiffer than an aluminum boom of the same lenght. The german Surf magazine has tested 24 all-/hybrid-aluminum and 7 all-carbon booms in their August 2011 issue (*). Lab results have shown that carbon booms are 2x to 3x stiffer than aluminum booms : compare stiffness value of 60-70 N/mm of deflection when a weight of 40 kg is hanging at the middle of a carbon boom with that value of 20-30 N/mm of deflection obtained with an aluminum boom under the same conditions. The Severne Enigma carbon boom and the North Sails Platinum carbon boom are the 2 stiffest booms of the test.

Cheers !

JM

(*): http://www.surf-magazin.de/service/aktuelles-heft/surf-82011-2/

kvda
27th July 2011, 02:13 AM
I do have two Neilpryde carbon booms (matrix 2000, 200-248 and 220-268); the're about 7 years in use and stil ok. 7 years for a Nautix alu boom is very good.

@JeanMarc: That test in the German Surf Magazine also showed that a carbon end in a aluminium boom doesn't make the boom stiffer, but it's much more expensive.
check the difference between the NP X3 and X6:
NP X3 € 230/ 27 / 22
NP X6 hybrid € 449/ 28 / 23

Jean-Marc
27th July 2011, 02:35 AM
There is also a Nautix NXtrem with alumin tubes in the front (ergal) and carbon tail.
Have you heard about or tried such combination? I'm afraid it may break because of stiffness difference.

The german Surf magazine has tested the Nautix NX-trem boom in August 2006 :

http://www.surf-magazin.de/test-center/masten-gabeln/gabelbaume/

Not a bad boom with regards to stiffness 5 years ago, as stiff as either a North Sail Silver aluminum boom or NeilPryde X3 aluminum boom which are labelled as "medium" stiffness by today's standard. However, this is an old-fashioned boom shape ("pinhead" style) and the front head is screwed to the body side tubing by 2 screws on each arm, which bond is prone to normal wear and tear of the holes/screws over time...

However, some new generation aluminum booms are 30% stiffer than that : Aeron OS Slalom boom, Prolimit Assault V-Grip boom & Severne Alu Race boom are the top 3 stiffest aluminum booms of the Surf magazine August 2011 test. All 3 are built with the new V-Grip-Form 32.5 mm diameter tubing that provides a much stronger stiffness under load than regular round or oval tubing.

Cheers !

JM

Jean-Marc
27th July 2011, 03:06 AM
@JeanMarc: That test in the German Surf Magazine also showed that a carbon end in a aluminium boom doesn't make the boom stiffer, but it's much more expensive.
check the difference between the NP X3 and X6:
NP X3 € 230/ 27 / 22
NP X6 hybrid € 449/ 28 / 23

Sorry, I don't agree. It's not zero difference. There is a very small ("sehr geringen") difference, both subjectively when riding both booms and objectively at the lab test (both with +10 cm and +44 cm extension). The carbon tail does stiffen up the boom. It's not spectacular I agree in the case of the X3 vs X6, but it's significant enough to be felt and distinguishable. Whether the price difference justifies or not the small gain in stiffness is another question of course...:)

Cheers !

JM

Farlo
27th July 2011, 03:37 PM
OK, thanks everybody. The max length I need is 2m18 so I may take a full carbon or hybrid if I find one at a decent price. Maybe the NXtrem as it is the very last one, but as JM says it is an old design. I can imagine that a carbon tail makes a difference. I've pulled out the tail of my shorter Tiger (even older but not broken yet) and noticed that it has become quite loose, though the head is still strong... apparently.

Floyd
28th July 2011, 02:36 AM
I used to break aluminium booms regularly;one a season !!! Stopped using them 5 years ago and not had any breakages since. (Use Amex Carbon Pro)

IMO carbon booms work out cheaper and make sails more stable;especially bigger ones. Give more peace of mind too. Dont think they are as light .(Amex arent anyhow)

I`ll never go back to aluminium booms. Lets face it we stopped using aluminium masts years ago ???

Farlo
7th August 2011, 02:41 AM
One more advice please. I've found a NP X6 200-250 and a North Platinum 170-220. The North is more expensive but a lot stiffer/lighter and would cover most of my sails. My dealer tells me there is no problem to use a full carbon boom at its max extension but I'm still hesitating. On my biggest sail I need 2.20 for rigging and then 2.16 max for sailing. Do you thing it is OK and will not affect durability? Thank you in advance

sergio k
7th August 2011, 10:52 PM
One more advice please. I've found a NP X6 200-250 and a North Platinum 170-220. The North is more expensive but a lot stiffer/lighter and would cover most of my sails. My dealer tells me there is no problem to use a full carbon boom at its max extension but I'm still hesitating. On my biggest sail I need 2.20 for rigging and then 2.16 max for sailing. Do you thing it is OK and will not affect durability? Thank you in advance

not sure what you mean by rigging max, but if sail max 216 and your boom is 220 max, you should be fine. I would check, just in case, if boom is wide enough

Farlo
8th August 2011, 01:17 AM
Hi Sergio, I need some extra length to plug the cambers on my Naish GP. The North may be a bit short so I will check anyway. My question was more about sailing with max extension. I've been told to keep a margin of ~20 cm on aluminium booms. Carbon is much stiffer of course, however I would not like to break such a beautiful piece of hardware.

Farlo
30th August 2011, 03:42 PM
Hi again, finally I took the NX-Black as I could not find a long enough (and cheap enough) used carbon boom. This leads me to another question: why is carbon so expensive? For instance today Nautix carbon's are TEN times more expensive than their basic alu booms. In the past the price difference was not so huge. Moreover older booms are looked for because "they were putting much more carbon at the time".

The usual explanation is "high demand from emerging countries" but this sounds like BS. Carbon is one of the most abundant material on the planet and there is no way we'll get ever short of it. I suspect the current price level to be greatly artificial because we have been convinced that carbon is sooo much better and we are ready to pay a lot more. I know this is an old topic and my purpose is not to complain, however do you have any idea of the reason(s) why is carbon so expensive?

UnregisteredFloyd
30th August 2011, 11:29 PM
I know everybody thinks I`m Mr Cynical but dont think the price has anything to do with the cost of production.... Its to do with what the market will stand... There is no way on earth a carbon boom can be worth 800+ but if sailors are willing to pay it then it will be asked !!! But if carbon booms last so long manufacturers will go out of business..... Planned obselesence and all that....

Plus .... My knew Amex Carbon isnt as stiff (or heavy) as my 5 year old one... Perhaps they will start breaking more now ????

Jean-Marc
6th September 2011, 03:39 AM
How much do you think your carbon boom is flexing under load while windsurfing in real life ?

Check this video out to discover how the tail of a NP X9 boom is bending under load :

http://www.youtube.com/watch?NR=1&v=0y87AgBBxMo

Quite impressive indeed..., especially considering that the sail is quite small (i.e., Overdrive 7.0 m2) with a boom lenght < 2 m long.

Other boom's tails look like stiffer than other, especially one with white/black/red stripes...:

http://www.youtube.com/watch?NR=1&v=zakHJEje9OQ

Cheers !

JM

Jean-Marc
6th September 2011, 04:29 AM
By comparison, this is how an all-aluminum boom (North Silver) is flexing under load while windsurfing in real life :

http://www.youtube.com/watch?v=JcEP0cJjrEA

The boom is way softer all over the arm tubes (especially when pumping the sail) than a carbon boom. Pretty obvious about how an all-carbon and an all-aluminum boom do flex in real life as compared to lab test results...

Cheers !

JM

Farlo
6th September 2011, 07:58 PM
Sure, after trying a North Platinum and a Nautix Jumbo (supposedly very stiff as well) it's pretty obvious that the rig feels more nervous with the carbon boom. Now is the flex such a bad thing, as long as it doesn't affect the profile of the sail too much? You may appreciate it after long hours/long distances. Masts of various carbon content have the same static flex but different dynamics. Is it the same for booms (i.e. combination of static/dynamic flex)?

PS: the NXtrem tested in German Surf Magazine is the regular alu version, not the hybrid one. That's why it sits between the NS Silver and NP X3. I wonder why Nautix discontinued the hybrid version. Will ask them at the next Salon Nautique.

Farlo
29th September 2011, 11:10 PM
Yesterday I was in Stuttgart. Next hall was a trade show on composite materials. During a break I could discuss with some of the guys. They told me that demand from China and South America notably is putting extreme pressure on all manufacturers. They also said that raw material (PAN) but also resins and other oil based stuff involved in carbon fiber processing have seen an increase of 30% last year. One added that it generates much more pollution than let's say metal work (admittedly you must consider the full product life cycle). Anyway it looks like high prices are here to stay.