Sue Pelling takes a look at the carbon fibre mast industry and finds out how movers and shakers are bringing the costs down...

Although carbon fibre spars have been around for more than a few years now it's only recently they've become more obtainable and affordable to the average club sailor. Like any new product or materials in the development stages, the process to establish a proven product is fairly long-winded. However, with more and more dinghy and small keelboat sailors notching up the results with their new radical, black sticks, it seems likely alloy masts could be on the way out.

But what are the advantages of carbon over alloy?
Despite the fact this manmade material is made from tiny feather-weight strands of fibres it's incredibly strong. Unlike an alloy mast, which when overbent will either break or take up the inevitable banana-shaped kink, carbon fibre will return to its original shape, in either one piece or two! And because dinghy racers are always striving to keep the weight down for optimum speed, reducing the amount of kilos up the mast to prevent pitching has got to be a massive advantage.

Construction methods
There is no doubt that the pioneers in carbon fibre mast construction are the cottage industry-style boatbuilders and mast makers who are passionate about their work. To find out about some of the different types of construction methods, I managed to catch up with a few specialist builders including Alan Jackson from Chipstow Boatyards. Jackson who's spent decades building beautiful wood Merlin Rockets and one-off development class dinghies, admits he's been bitten by the carbon fibre bug. 'We started experimenting with carbon fibre masts in 1998,' said Jackson, 'and we were lucky enough to have top Merlin sailor Mike Calvert on our design team which works very well. Mike is detached enough to tell us exactly what he thinks about the mast and how we could improve it. From my own sailing point of view, I can't believe the difference the carbon fibre mast has made on my boat; it's like putting a sophisticated gearbox in, it's transformed my sailing and made it a lot easier.' Jackson's method of construction is using a hand-made female mould which is very labour intensive. 'I spend about 30 hours putting a mast together which includes fixing the track and and feeding the draw lines for the halyards. A finished Merlin Rocket mast, ready to go is £1,450.'

Linton Jenkins is another specialist dinghy boatbuilder who's keen to develop carbon fibre masts. 'I've been working on International Canoe, National Twelve and Merlin Rocket masts,' says Jenkins, 'using the male mould mandril system and I hope to get involved with International Fourteens this season. Although I'm producing straight tubes with tapered top sections at the moment, I'm a firm believer that the aerofoil section is the way forward. However, until I have £5,000 to invest in the tooling, I'm making the most of what I already have.'

At the other end of the market is Selden Masts who are geared up for mass production with the recent purchase of a filament winding machine. This latest piece of kit which costs approximately a quarter of a million pounds is the only one of its sort in Europe and is apparently an extremely accurate way of producing carbon fibre masts. Once the computer on the machine has been fed the correct class data, a mast can be wound in just 15 minutes! Obviously there's a lot involved in the setting up of the machine, producing disks with the the critical data on for each class but once that's done, it's simply a matter of threading the four bobbins and pressing the right button. One of the many advantages of this machine is being able to produce a mast with the correct angle layers of materials and thickness of fibres in certain stress areas. 'Our machine is able to lay the carbon fibres in all orientations to resist all the mast loads including twisting loads from the kicker and gooseneck etc.' says Chips Howarth - Selden Business Manager.

The 12,000 strands of carbon on each of the four bobbin spools are pre-pregnated and fed on to the rotating mandril at the correct tension and angle. Once the mast has been wound, it's then wrapped in polythene and baked in the oven for four hours. In this process the alloy mandril expands, the heat wrap shrinks, and with a combination of heat and compression, the pre-preg goes off and offers excellent consolidation. 'Another advantage of the filament winder,' says Howarth, 'is we can produce profiled (teardrop) sectioned masts.'

The interesting decision that Selden made was to produce their masts in two sections joined by a step to create a rapid change in stiffness. 'This rapid change in inertia,' says Howarth, 'will allow the rig to become more automatic and efficient a bit like a windsurfer rig upwind. On the gusts, the top of the mast will flex but the bottom of the mast will remain solid, keeping jib luff and middle/lower mainsail leech tight. The other advantage of a twin section mast is that we can produce a range of top masts for different weight sailors in a variety of classes such as the International Canoe or any open class.'

While carbon fibre hasn't quite taken over the mast construction market yet because they are still approximately 2.5 times the cost of alloy masts, there is no doubt the continuous development and increasing competition will result in lower prices, possibly as low as just one and a half times the cost of an alloy mast!

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