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A common question is ‘which is stronger – a light and stiff carbon mast extension or solid alloy model?’

Of course, an aluminum extension will most likely bend than break, whereas in the unlikely event of a carbon model failure you’re looking at a snap, leaving you with some work to do to get home – and maybe even a damaged mast and/or sail too.

Here are some notes to help you find the right mix of weight, performance, strength and price to suit your budget and needs.


The issue of which material is stronger is slightly more complicated than it first appears.

Wall thickness on all types of material plays a major part in structural integrity.

Regardless of material, Reduced Diameter Mast (RDM) extensions have more relative wall thickness and so are stronger overall, yet Standard Diameter Mast (SDM) extensions have the best weight-to-strength ratio.

SDM and High Tension Slalom/Speed Sail Use

In the case of SDM extensions, which are generally under more strain when used with large, camber-induced sails this weight to strength ratio is a potential plus point towards performance.


However, although carbon extensions are generally much lighter, which in terms of momentum in lulls or early planing in light wind is something you might think is important, in the case of windsurfing, mast extensions are in the middle of the board/rig combo, so the effect of any extra weight is far less than if that mass was ‘swing weight’ on the outside edges of a sail clew or head, a nose the board and etc.

More tips on choosing mast extensions

Breaking Point

Carbon will more than likely snap before aluminium bends, so we would ultimately recommend racers use a reinforced aluminium extension over carbon unless they really value weight or just love the look and feel of carbon.

Bear in mind though that not all carbon extensions are 100% made of carbon  - such as the base area that’s often made of nylon or other plastic - compared to all-metal/aluminium models that are produced entirely from aluminium/stainless steel etc.

Of course, aluminum-reinforced, Heavy Duty (HD) carbon models do offer some of the best of both worlds with stiffness, partial weight reduction and protection against snaps.

That said, well reinforced, HD aluminium extensions are also very strong and not that heavy, but are also, depending on what grade of materials are used, liable to suffer from corrosion over time.

Remember that all types of extensions are likely to have pulleys/rollers and cleats made of some type of metal, be it brass or aluminium or even marine-grade stainless steel, which are all potential corrosion targets at some point in their lifespan. 

In the Surf

For wavesailing there’s not much in it as 99% of modern rigs use RDM masts and so choices are made more on weight and price rather than strength alone.

Even the most basic alloy model will already possess a good amount of durability and deliver a satisfying length of service for most riders and usage.

Radical wavesailors should consider whether they value carbon for optimum performance and cosmetics, or HD aluminium models for ultimate reliability, such as from landing hard jumps or wipeouts in heavy conditions.

And once again, the alu reinforced HD carbon option delivers a good mix of both reliability and performance.

Visit the Knowledge Section for more information on choosing the right windsurfing equipment for you