fbpx Windsurf MagazineRDM MASTS FOR AUTUMN & WINTER | Windsurf Magazine

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Once upon a time, for those that started windsurfing last century, all masts were 48.5mm wide before some bright spark, tired of snapping his spars and subsequently shredding his sails looked a little further out of-the-box and came-up with the concept of a thinner mast with increased wall thickness for added strength. Here’s some food for thought on picking RDMs with the fast-approaching winter Wavesailing season in mind.

These days, pretty much all sub-6.0 sails (say masts below 430cm long) are designed to rig with a ‘skinny’ or Reduced Diameter Mast (RDM).  The general theory is that the increased internal width makes for a tube that’s more resistant to radical flex and bending forces and, in many cases, that RDMs can have a wider range of reaction behaviours specified by the more extreme scale of tapers in the cylindrical ferrules used in their manufacture. If you’re primarily into wavesailing then this is good news and a vital piece of equipment for surviving a pounding in the impact zone.

The good news is that if you’re switching from Standard Diameter Masts (SDMs) you won’t need a new boom, as many RDMs come supplied with an adaptor – or you may even find you’ve already got the correct shim supplied with an RDM/SDM compatible boom. The bad news is that you’ll need to find a mast extension solution too, but, once again, these are often superior in strength as well and, if chosen correctly, can last longer than a cockroach in a nuclear meltdown. Here’s some snippets of wisdom from some of the most experienced retailers in the UK, and some contact details of the main distributors who can point you towards your local dealer.



We recommend most people select a 400 for the widest range of use in their wave or high-wind quiver. You can buy 30 and 60% carbon content models – the 60s are generally good value and fairly strong – if not a little heavy – with price points around the £200 mark. With the  ‘100%’ models (Note it’s impossible for a mast to be made of 100% carbon as there is resin and tape et cetera also in-the-mix), you generally get a lighter mast with a faster response rate. What that means is that the rig is tighter and crisper with a whippier reaction in use. If you can afford it, the top-of-the-line 100% models often sail better. You’re better-off choosing the shortest mast to go in most sails as longer masts can be easier to snap under stress, although heavier riders often like the added stiffness of longer masts. Modern Compact-style sails like the shortest mast they can get away with generally. The 400 works well as it can be flexy and reactive enough for your larger sails – such as 5.6s – and is stiffer and tougher in the stronger winds paired with smaller sail sizes. reactivewatersports.co.uk



For wave sails, I always think it’s about getting the right balance between price and durability. Most people, bar hard-core riders, will be happy enough on a 75-80% content mast. Sometimes, these can often be stronger than 100% masts – the compromise you make though is increased weight. The only way to make a mast lighter is to reduce the wall thickness – so that means specifying stronger material throughout and hence the higher carbon content of the overall finished product. With a 75% mast you have more glass, which is heavier, but with a thicker, arguably stronger wall. Regarding curves, in terms of wave sails, if you have a mixed quiver of sails from a range of brands then a constant curve mast is going to be best. If you’re brand-loyal or simply have more sails from lofts favouring one curve or the other then pick the right one for those manufacturers. For example most Gaastras/Vandals, MauiSails, and some Severne RDMs are hard-tops, whereas NeilPryde and Tush tend to be soft-tops, But constant curves will be a good long-term pick as you tend to upgrade your sails more frequently than your masts so bear future compatibility in mind. There’s also a slight trend of sails shifting towards more constant curves we’ve noticed, and it’s fair to say most brands RDMs are developed on constant curves. boardwise.co.uk



I always think that if you can afford it the 100% mast is best. You get the greatest response with no negatives, especially if a good grade of carbon is used. Many 100% models also feature additional materials such as Kevlar for added impact resistance – especially in the boom area for example. A mast’s the most important part of the rig and lasts a long time and will likely outlive your sails. To choose the right mast for your current and maybe future sails, I recommend you go to your dealer and have them assess your individual case. Sails, regardless of their ideal quoted bend curve, have such a wide range of behaviours when rigged with different masts, so you might need to see how yours react first. roho.co.uk



When a customer wants to buy a new mast, the first question we ask is “what sail sizes / brands do you have?” We feel it’s important to match the sail / mast specifications to get the best out of their equipment. Tools such as the Unifiber Mast Selector Tool are a great reference point for both us and our customers. Whilst it’s always preferable to have the highest carbon content mast possible, 100%, we’re finding that most of these are outside of the average windsurfers budget, hence the popularity of 80% carbon content. For those on a limited budget we have a range of 60% and 40% RDMs, we also put together cost-effective rig packages using 40% RDMs which get beginners and intermediates into RDM masts at an early stage. One area which is a bone of contention is that some brands seem hell-bent on going their own direction with regard to bend curves, Flex Top, Constant Curve and Hard Top are a source of confusion – oh for the day when there is a single bend curve standard! And why are the brands so afraid of publishing mast curve specifications? In common with other shops, we hardly sell a SDM mast under 460 these days, RDM have certainly become the product of choice. 340 masts are also becoming more popular for sub 4m sails making the rig more manageable and avoiding lots of mast sticking out at the sail head! 4Boards.co.uk


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