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Technical
The rig - Should you go for carbon?
published inn°188mar. / apr.
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When designing his IC36 catamaran, the manager of the Independent Catamarans shipyard did, of course, pay great attention to the rig: So, the mast? Aluminum or carbon? Jaromír Popek shares with us his studies and the feedback gained from his sea trials. And this will give some food for thought when the question of a carbon option is put forward by a builder, but also if you’re undertaking a performance-oriented refit or perhaps following major damage to the original rig.
The composite or carbon ones just do not chime. Perhaps, that’s a bit of a shame, from a music-lover’s point of view, but for many other reasons this technology has its proper justification.
Multihulls and their owners carrying such rigging are duly proud of this hi-tech equipment and the black color, which is the natural color of carbon-fiber, often draws attention to it. Ambitious ‘aluminum’ sailors sometimes try to mimic this phenomenon too, but only by the use of black paint on the masts and boom surfaces. I should also mention the fact that while black paint on the surfaces of anything on a multihull looks confident and sexy, it is also quite impractical in terms of maintaining a reasonable surface temperature. After all, climbing a mast in a marina that has a surface temperature of well over eighty degrees at midday requires a bit of skill and appropriate clothing and shoes. Anyway, who cares, when you’re then leaving harbor, you’re suddenly king, the center of attention and you enjoy the respect. But the issue is not all that simple. If you opt for a carbon mast, the rest of the rigging needs to match. No stainless-steel vents, but a lightweight carbon or performance fabric.
All of this together brings with it a massive increase in performance, increased safety, but also higher costs.
Carbon vs aluminum
In terms of technical properties, the carbon mast has an advantage over the aluminum mast in several respects. It is at least 35 to 45% lighter and has a lower center of gravity, which is a very important feature in terms of dynamics, knock effect and safety. It tends to be considerably stiffer, but at the same time retains some flexibility for handling overloading. It just won’t chip, but if it does and there is damage, it’s easier to repair than aluminum.
Lighter, stiffer, more dynamic
So the aluminum mast is heavier, but that’s not the only thing going on here. The thickness of the aluminum mast profile is uniform along its entire length. At the time of sizing the mast, the yard selects from predefined profiles available in the market, taking into account the «righting moment», or the multihull’s heeling effect, with a precise determination of the load on the burdened parts of the boat and the mast itself. The carbon mast is subject to many calculations, one of which is the identification of structural areas to be fitted with additional layers of fabric with the appropriate fiber direction exactly where such reinforcement is needed. On the other hand, the profile wall is made thinner where possible, so that the overall weight balance achieves greater savings, and the center of gravity shifts significantly lower towards the waterline. The stiffness and flexibility give greater ...
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Emmanuel VAN DETH
Frankly, we can find two advantages in an aluminum mast compared to a carbon mast:
- it is undoubtedly easier to sleeve in the event of breakage (and lack of budget to buy a new one - we remain on the same subject).
- In the event of rough conditions leading to a capsize, the aluminum mast can break, unlike the carbon one, which will have to rely on the guying to eventually fuse.
Carbon is definitely good pretty much everywhere else!
Emmanuel van Deth
Dominique Bovey
Good article, although a bit too much centered on advantages only for sailing. However doesn't an aluminium mast advantages in other aspects than costs?