Carbon or aluminium boom?

[<SG Windsurfer>]

Hi I would like to ask your opinion about what is the difference between carbon and aluminium boom. The cost difference is very big so I want to be sure I am getting money worth.

thanks for your answers.

[sukhdev]

Several differences:

weight - for example 2 similar sized booms from Chinook:
Carbon    Giant Slalom 167cm-229cm 5.04 kg
Aluminium Giant Slalom 167cm-229cm 6.24 kg
The carbon is more than a kg lighter. This is very significant in transitions where the weight difference becomes swing weight. Try holding one kg out at the end of  your arm and you get the idea. A lighter rig is easier to trim, easier to waterstart etc.

Stiffness - carbon booms win out by a big margin here. In a gust, the last thing you want to happen is for a boom to flex, thereby increasing the draft of the sail and increasing the power; net result would be reduced control in gusts.

Cost - Carbon is very much more expensive, between 2.5 to 3 times more.

Durability - Some brands of carbon booms are famous (infamous?) for durability problems, mainly the head cracking. So far we have been very happy with HPL and Chinook. Aluminium booms give less problems initially but over the long term are prone to corrosion problems.

If you are using large race sails, 9.0 and above then carbon is preferred. The difference is very noticeable. I had a chance to tune someone's 9.0 Retro, only difference with that and my 9.0 Retro was the boom, same masts; yet I could easily feel the way the rig reacted was different.
If you are using 10.0 and above you pretty much have no choice, its carbon or almost nothing else. For medium sized freeride sails like GTX, GTR, Retro etc you can easily get away with aluminium if cost is an issue.

One other thing, use adjustable outhauls, its like having a gear shift on your boom...
 
 [ 13. December 2002, 09:19 PM: Message edited by: sukhdev ]

[<SG Windsurfer>]

Sukhdev,

thanks for the information. If I buy second hand carbon boom what should I look for as problems?

[Meng]

SG,

I had an unpleasant in seliing my NP carbon boom to of my wsf buddies.
I used for about 2 mths and sold it to him for 'brother price'. Just about a week later, the boom broke. I was rather 'paiseh' or felt bad for selling the defective boom to him.
 
Conclusion, u can get 2nd sails but not for boom or mast cos, u can't repair it if broken.
Brand new = warranty (despite huge cost)
2nd hand = no warranty

 

[sukhdev]

Meng is right, but if you must buy a 2nd hand carbon boom look for these things:

Old carbon booms with aluminium tube heads: Don't touch these, arm/head linkage breaks very common once aged.

fiberspar booms with carbon heads:
-check the ring lock for the adjustable arm, these slip once worn, can be replaced (if you can find the spares, Ben does a good job).
- check head/arm connection; if there is a uneven gap on the 2 arms then one is twisting out and the inner glue is gone.

NP etc : the older ones (black grip with grey matrix marking), check the head, also check the tail piece, in some cases the single rivet is prone to being loose (can be fixed)

HPL : old ones with single lock clip can stick. Newer ones with double clip give much less problems. For newer ones, check if the clip needs cleaning.

Chinook carbon : talk about durable..only thing to check is the rivet pin on the brass roller pulley in the  tail piece. If loose it will need a touch of loctite to fix it.
 
 [ 18. December 2002, 12:19 AM: Message edited by: sukhdev ]

[<SG Windsurfer>]

Sukhdev, thanks for a very honest answer, at least somebody in Singapore knows the technical things of the sport.

[<Grey>]

Sukdev

Is it possible to reinforce an old carbon boom? I have a fiberspar about 3 years old now which I used for 8.3. Will the reinforcement help it last?

thanks.

[sukhdev]

Its possible to reinforce the head. In fact up to recently most pro sailors did that for fear of booms breaking during competition. Newer head designs don't need this.

Basically it requires extra layers of carbon and glass to be laid up. Not an easy job, painstaking. You might as well use the cost towards a new boom. If you are using a recreational 8.3 then a aluminium boom should be ok and they are much much cheaper than carbon.