Masts
If you don't buy a new complete rig with the components recommended by the manufacturer from the same company, you are forced to delve a little deeper into the world of masts in order to find the right mast for your sail. Here you are confronted with a multitude of data and figures. Here you can find out what is important for your purchase - and what you can safely forget.
RDM/SDM
RDM (Reduced Diameter Masts) are the modern masts with a reduced diameter, also known as "skinny". Compared to their thicker predecessors, the SDM (Standard Diameter Masts), they make sails much more manageable and user-friendly. Thanks to their thicker wall thickness, RDM masts are also more stable and more resistant to breakage. RDMs were introduced around 2004/2005. Nevertheless, SDM masts have continued to prove their worth, particularly due to their greater rigidity, which is an advantage for large sails over 6.5 square metres and in high-performance regattas.
You can still find shorter SDM masts from earlier times on the second-hand market, which were designed for smaller sails. However, these hardly fit into modern sails and are therefore almost no longer in demand. "For example, I haven't sold a 430 SDM for a long time," says surf tester Frank Lewisch, who knows his way around thanks to his work in the shop. For orientation: sails between 3.3 square metres and 6.5 square metres, with mast lengths between 340 and 430 cm, are almost exclusively rigged on RDM masts. Sails from 7.0 square metres to 9.6 square metres, with mast lengths of 460 to 490 cm, often require the thicker SDM. In the transition area, especially for freeride and freerace sails, both mast types may be suitable. The manufacturer's recommendation should always be taken into account here.
More windsurfing basics:
Mast length
The length must be correct. The English term luff refers to the length of the luff and is usually printed on the sail. The mast you want to buy should somehow match this luff length. "Somehow" because you have a certain amount of leeway. Masts are available in length increments of 30 centimetres (340 cm, 370 cm, 400 cm, etc.). As you always need a master extension for rigging, any intermediate length can be set. In our experience, however, masts should not be extended by more than 40 centimetres, as otherwise the sail becomes noticeably soft and performs less well. With a luff length of 440 centimetres, for example, it is therefore advisable to lengthen a 430 cm mast by ten centimetres instead of a 400 cm mast by 40 centimetres! The mast may only be too long if the sail has a vario top (adjustable webbing at the top of the sail) through which it can protrude at the top - this may then be up to 20 centimetres longer than the specified luff length. With luff lengths of 432 centimetres, for example, there are often two mast lengths to choose from: a 400 with 32 centimetres or a 430 with an extension of just two centimetres. Two things should influence your purchase decision here. Firstly: Longer masts are always harder. The harder the mast, the tighter the sail feels. This can be an advantage for heavy riders (> 95 kilos), but in the hands of lighter surfers (< 65 kilos), the hard mast often means that the necessary profile is no longer pulled into the sail - a shorter mast would be more suitable in this case. Secondly, how does the mast fit in with the rest of your sail range? If you only have smaller sails anyway, you may not need a long mast at all. If you are planning to buy larger sails, you will need it sooner or later.
IMCS value
The IMCS value (IMCS = Indexed Mast Check System) is a relic from the past and is very limited in its informative value. It indicates the mast hardness - the lower the value, the softer the mast. However, as there are no differences in hardness within one and the same mast length (for example, all 400 masts have a hardness of 19, all 430 masts a hardness of 21, etc.), there is really no need to think about this value at all.
Carbon content
The higher the carbon content, the higher the quality, but also the more expensive the mast. A mast made of 100 per cent carbon is particularly light, but must be handled very carefully, as even minor damage can lead to breakage if the mast is subjected to a load. You should therefore carefully consider what exactly you need and what you are prepared to invest. In practice, masts with a low carbon content tend to react slowly when surfing, especially in choppy water. High-quality carbon masts, on the other hand, return to their ideal position more quickly, which makes the sail appear lighter and more responsive and theoretically increases the surfer's speed. In practice, however, riding ability is usually the decisive factor. Ambitious hobby surfers will find masts with 50 to 80 per cent carbon content to be a high-performance yet affordable option, with performance and handling barely affected in comparison to the more expensive 100 per cent carbon masts. For beginners who are just starting out with their first attempts at gliding, an inexpensive mast with a carbon content of 30 to 50 per cent is perfectly adequate.
For hobby surfers, masts with 50 to 80 per cent carbon are a sufficiently powerful option.
Bending curve
When it comes to the bending curve of masts and you are unsure, you should follow an important rule: the golden mean. This is because the bending curve of masts is a complex and often debated topic in the windsurfing world. The various sail companies are not entirely innocent of this, as they all follow their own recipe for a successful combination of mast and sail and also want you to only combine products from their own brand wherever possible. Depending on how the mast bends, the profile of the sail changes and with it the entire sailing behaviour.
With the Constant "Curve" you take the least risk.
Some companies swear by a Flextop, where the upper half of the mast is softer and therefore bends a little more than the rest. Others rely on the constant curve, which is characterised by an even, round mast curve. Last but not least, there is the Hardtop, where the mast is particularly hard in the upper section. Fortunately, in recent years more and more brands have switched to the golden mean of Constant Curve, which fits almost all brands and models quite well. So if you buy a mast that is not from the brand of your sail, you run the least risk of error with a mast that has the Constant Curve.
Mast extension & base plate
The extension and mast foot plate must be compatible so that the board and rig can be connected later. Fortunately, the pin system has become widely accepted on the market - 95 per cent of base plates have a thin metal pin that is inserted into the extension to connect the board and sail. Nevertheless, there are alternative systems (e.g. Quick Release or US Cup) that only fit into corresponding extensions. So make sure that the base plate and extension are from the same system.
The diameter of the extension and the mast must also be compatible. The extensions are labelled RDM (Reduced Diameter) and SDM (Standard Diameter) in the same way as masts - the designation of the mast and extension must match, otherwise the extension is unusable.
Extensions are also available in different lengths (e.g. 45 cm, 30 cm, 15 cm). Depending on your needs, one or the other makes sense. For example, if you only use two sails in total, both of which only need a few centimetres of extension with corresponding masts, you can consider choosing a shorter extension to save yourself the superfluous weight of the upper adjustment range. However, this is only a matter of a few grams; in general, an extension with an adjustment range of 30 centimetres is most commonly used. And finally, there is the good old question: carbon or aluminium? The majority of surfers will quickly notice the difference between a carbon and aluminium boom - but not so much when it comes to extensions. Here you can safely choose the aluminium version. An extension made of carbon is merely very light, but also correspondingly expensive, without any noticeable advantages for non-professionals.
Booms
Length
The "Boom" label on the sail indicates the required length of the boom. As sails can be trimmed either bulbous or tight at the outhaul depending on preferences and wind conditions, many manufacturers specify the boom length with a tolerance of plus/minus two centimetres. When selecting the boom, however, you should consider allowing a little more leeway, as the specified dimensions are not always exact. For the largest sail, it is advisable to allow at least five centimetres extra length. For example, if the sail says "Boom 195 cm", you should buy a boom that can be extended to at least 200 centimetres.
In general, it is advantageous to have more room to manoeuvre, as a less extended back end makes the boom more stable compared to a shorter model that has to be fully extended. If the boom is fully extended, there is an increased risk of it being damaged in a fall. Ideally, you should choose a boom that covers three to four sail sizes so that you only need one boom. The adjustment range is usually clearly printed on the spars.
Carbon booms offer some advantages, but aluminium bars can also provide a lot of surfing fun.
RDM/SDM
This refers to the size of the cut-out at the front of the boom for attachment to the mast. Some small, modern booms up to 200 centimetres in length - for wave/freestyle use - are nowadays designed exclusively for thin RDM (Reduced Diameter) masts. The recess within the clamp is then too narrow to attach the boom to a thick SDM (standard diameter) mast. Most other booms (especially from 200 centimetres upwards) for larger sails are usually suitable for both mast types. This is because a removable adapter is simply integrated into the wider recess on the front piece, which can compensate for the different diameters. If you buy a boom that does not come with such an adapter, you have the option of buying a universal adapter. This is often supplied with the purchase of a skinny mast.
Carbon/aluminium
Carbon booms offer numerous advantages: they are lighter, stiffer and more stable and often have a smaller diameter, which makes them more comfortable to hold. If price were not an issue, the choice would be clear: carbon fibre! As the boom is the direct connection to the sail, it has a significant influence on how the sail feels in the hand. Aluminium booms can also provide a lot of surfing fun and are not an immediate limitation for both beginners and experienced surfers, but we can still recommend everyone to go for a carbon boom if possible. Heavier surfers in particular, those who jump a lot or those who are travelling with powerful camber sails should seriously consider the stiffer carbon boom and not save money in the wrong place.
