Sparring Partners – SDM and RDM Masts Test Results

Sparring Partners: Mast Diameter and Carbon Content


Carbon: 30% Weight: 2.33kg Price: £225


X3 RDM Results

The X3 RDM was the heaviest mast of the group, and felt the heaviest on the water. Interestingly, the weight was most noticeable not at the sail head, but actually somewhere around the front of the boom. The effect of this weight was most apparent when the sail was being manoeuvred – e.g. beachstarting, gybing, forwards, etc. When locked in and sailing it was much less of an issue.

Of all the masts on test, the X3 RDM gave the sail the smallest wind range. At the top end the sail felt more ‘baggy’ and held the power on the back hand more than any of the others. At the bottom end (early planing) it felt the heaviest and least responsive to get going. It was also noticeable that there were fewer tuning options available to you on the beach. The X3 RDM was pretty much a one-set combination, whereas the more expensive masts seemed to allow a little more tuning scope – particularly on the downhaul.

Generally, on the water the sail felt softer, springier, baggier, and had a slightly more back-handed pull position than the more expensive masts.

Having said all this, the X3 RDM mast was in no way bad, and even our most advanced Clones were quite happy using this combination. Compared to the X9 SDM there was a noticeable difference in feel, weight and comfortable wind range, but bearing in mind the more than noticeable difference in price (£225 vs £500) it’s hard to criticise this mast, particularly as you get the added strength and durability associated with the RDM.



Carbon: 30% Weight: 2.25kg Price: £200


X3 SDM Results

The X3 SDM is the cheapest mast here, and it’s a little lighter than its RDM equivalent. The weight difference between the two X3s wasn’t really apparent on the water, and again, the extra weight of this mast over the more expensive versions was most noticeable not in the head but lower down (around the front of the boom), and particularly when manoeuvring the sail.

Our Clones preferred the narrower feel of the RDM for handling. It’s much easier to get a grip with your hand mid-manoeuvre, but they did agree that the SDM offered slightly more performance. The sail felt more forward pulling, stable and responsive with the SDM version. It gave a little more tuning versatility and a slightly better, more comfortable wind range.

In terms of performance we’d put the X3 SDM in similar territory to the X6 RDM (albeit with a different characteristic), but it was noticeably heavier to manoeuvre and you potentially lose out on the strength and durability of the RDM.

Overall, for the cheapest mast in test, it offers decent performance for the price. However, you will notice the weight and we can’t help but feel that SDM masts in wave sails are a dying breed.



Carbon: 50% Weight: 2.02kg Price: £315


X6 RDM Results

Perhaps not surprisingly the X6 RDM felt like it sat comfortably between the X3 and X-Combat in terms of performance. In terms of weight it also sits right in the middle – 0.3kg heavier than the X-Combat RDM, and 0.3kg lighter than the X3 RDM. The carbon content is actually skewed a little closer to the X3, with just 50%. The price does reflect this though, with a price point closer to the X3 RDM than the X-Combat.

On the water the sail holds its power on the back hand a little more than the X-Combat in the gusts, and didn’t have quite the same wind range or tuning range (as it goes too floppy, too quickly under downhaul), but it was a noticeable improvement on the X3 RDM. It still feels a little ‘soggier’ to react than the X-Combat or SDM X6 & X9 masts.

That said, it’s really hard to quantify the differences. In terms of performance, most people will notice a difference between the two ends of the spectrum: X3 and X-Combat RDMs. But comparing the X6 RDM with one of these two requires a bit more attention to appreciate the difference. It is noticeable, but it isn’t massive. The biggest difference to most will probably be the handling weight.



Carbon: 55% Weight: 2.00kg Price: £365


X6 SDM Results

In similar style to the X3 RDM vs SDM, we felt that the X6 SDM gave the sail a slightly more favourable character in terms of performance than its RDM equivalent. The SDM mast seems to lock the pull further forward and gives a crisper, sharper and more responsive feel. It also allows a little more versatility when it comes to tuning.

Again, the downsides are similar to those of the SDM X3. You lose out on the RDM strength advantage, and with the whole industry leaning more and more towards RDM masts (particularly for their wave ranges) we do wonder if you’re better off accepting the future now and kitting yourself out with the correct extension and boom set-up to suit the RDM masts. The SDM version of the X6 is £45 more expensive than the RDM (and virtually the same weight).



Carbon: 90% Weight: 1.72kg Price: £415 (X9 RDM)



NeilPryde weren’t able to supply us with an X9 RDM, so we had to use the older X-Combat – which is basically the same mast by a different name.

In terms of performance, this was in our opinion the best match for the sail – particularly in chop and waves. The X-Combat RDM didn’t lock the power in place quite as well as the X9 SDM, but was better than everything else in the group (X6 SDM included).

The X-Combat had enough flex to give the sail a forgiving nature, which helped in chop and when landing jumps, etc, but was responsive enough to give great performance throughout the wind range. At the top end the sail remained stable and fairly forward pulling, while at the bottom end it was light and responsive enough to get planing easily – a noticeable improvement on the other two RDM masts.

Compared with the X3 and X6 RDM masts, the faster response of the X-Combat converted the springy, slightly soggy feel of the other two RDMs into a very positive, forgiving feel that was still able to deliver sharp performance.

Combine these positive attributes with the light weight (1.72kg), handling and additional durability of the RDM mast and you have what was in our opinion the most desirable mast combination on test.



Carbon: 100% Weight: 1.47kg Price: £500


X9 SDM Results

The X9 SDM mast is incredibly light. This was really noticeable in handling and also at the bottom of the wind range when it came to getting planing. It was also the stiffest feeling mast of the group, which gave the sail a very sharp and crisp feel. It almost felt a little too stiff for our liking in chop and waves, where we prefer the slightly springier X-Combat RDM.

On the beach we were able to get the best range of settings out of this mast, and the sail set with a nice bit of shape at the front. This provided really good stability and light handling even at the top of the wind range.

While the X9 SDM was unbelievably light and offered extremely good performance in the hands, we still find ourselves favouring the X-Combat because of its slightly springier, easier-going nature and also the extra durability associated with the RDM mast.



Let’s start with the results of SDM vs RDM. Overall it seems that, like-for-like, SDM masts still offer a slightly better overall performance than RDMs. They lock the power further forward and give a crisper, more responsive feel with a little more tuning flexibility. RDM masts generally hold the power a little further back and make the sail feel softer, springier and a little more ‘baggy’ in the hands. The exception to this was on the highest carbon content versions, where the SDM mast actually felt a little too stiff in our opinion (to suit the characteristic of the sail), and the RDM with its extra flex gave a more rounded, easier-going performance. When you factor in the extra strength of RDMs and the massive trend towards them, it’s really quite hard to advise against them, particularly if you can afford one of the higher carbon content versions.

The results of our test on carbon content are pretty much what you’d expect to find – the more the better. Higher carbon content masts generally gave a lighter feel in the hands (most noticeable through manoeuvres) and gave the sail a better wind range – crisper, more responsive performance at the bottom end and easier, more stable handling at the top end. So, is it worth paying the massive price difference for the higher content masts? Being completely honest, the difference in performance is noticeable but not massive. The sail wind range increased by maybe 3-4 knots between the highest and lowest carbon contents, and there was definitely a noticeable difference in weight (particularly lower down in the sail, around the front of the boom). For sure, we all preferred the 100% carbon masts, and there’s no doubting that the sails performed better with them. But at twice the price the higher carbon content masts were definitely not twice as good. Whether it’s worth paying for the lighter feel and crisper performance is up to you…

Please note that the results of this ‘test’ were based entirely upon the NeilPryde range in the 5.4m size. While they should give a good overview of the differences across the marketplace, they may not necessarily be accurate for every brand or every size. It’s also worth noting that SDM / RDM preference is sometimes dependent upon the rider style and weight, where SDM may be more applicable to bigger sails (e.g. 5.8, 6.2 etc) and heavier riders.

Photos: Daniel Pritchard

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