Aluminium and Carbon Fiber Mast

Today we will focus on the developments of aluminium and carbon fiber masts.

        Firstly, the aluminium masts were developed during the second World War. One of the first examples of its apparence was the J-Class : Shamrock V (picture below). The real advancement was the strength of the aluminium alloy, it has been noted that the alloy increases the mast's strength by 20%. In addition, the plate thickness can be reduced which decreases the weight of the overall mast. Thus, giving the ability to add more load. This material also has excellent corrosion resistance which directly lowers maintenance costs. In the industry, there are two types of aluminium alloys : 
For a corrosive environment, we have the non-heat treatable 5000 and then we have heat-treatable 6000. 
Let us compare both of these. The 6000 is stronger but less corrison resistant than the 5000. So, if we take maintenance costs into account the 5000 is more economical. To note, it's the most used one. 
    However, aluminium isn't number one for manufacturing, as steel stands for the most used material in the shipbuilding industry. Steel gives more mechanical properties and low manufacturing costs. For a reminder : the material cost of building a ship represents 1% to 2% of the total cost of the ship. We can see the dominance of aluminium usage on more performant vessels, and steel usage is more important for high capacity vessels, a taker for example.
   There's a notable transition towards aluminium overall because it brings much higher recycling value in comparison to steel. So, aluminium shipbuilding has a proven and bright future!

        Secondly, let's discuss Carbon Fiber masts. This innovation was introduced in the 90s.
A Carbon fiber mast can be manufactured as a lighter and stiffer mast in comparison to an aluminium one. It allows for the improvement of a better performant rig. Where you can see its presence is at the America's cup.
For manufacturing a carbon fiber mast, there are 2 methods : 
Either with the use of a standard section mould that produces a uniform section for the whole mast. This method is noted as the cheapest one because the mould can be used more than once. Or, you can use a more specific mould which allows for more attention to details depending on what is demanded. However the mould is based on a one time usage only.
    In order to optimize the sails shape, the bend of the mast is very important as it flattens the sails and allows to increase wind usage. A carbon fiber mast can be manufactured with precise control orientation, thus making it possible to have a mast with the correct bending characteristics. If you're looking for specifics and details that is method number 2 and it's at a more pricy production cost. 

     Finally, the carbon fiber masts help a lot with performance, reduction of weight but they come with a price tag. With the increased labour it demands and cost of additional materials, a typical carbon fiber mast will be approximately 7 times the cost of an aluminium one. Yes, it's quite a big multiplier!  

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