Windsurfing 101 ... Masts Part 1

Masts:

What is a mast for and why should I care about carbon content and stiffness?

Good question!

Because without knowing what the mast does how can we make sure we get the right one? The mast provides a sail with three things; shape, response time and flexibility. Changing any one of these elements makes for a drastically different feel on the water. So let’s get right to the bottom line and de-mystify THE MAST!

It Keeps the Sail in Shape:
When properly rigged, each sail has a shape at which it performs best, and if the wind constant and the water mirror flat, the sail would never deviate from this shape. Unfortunately, gusts and lulls change the shape of the sail and the water surface kicks the board around, making the rig constantly move and change.

The best masts will keep the sail in the right shape for the greatest length of time. The sail may distort radically as a gust tries to turn the rig, board and sailor downside up, but when the gust has passed the sail must be returned to its 'right' shape as quickly and painlessly as possible - the faster the mast gets the sail back into this position the better it will feel. This is why carbon was introduced on the market and made the older fiberglass masts go the way of the dodo.

So in general the higher the carbon content of a mast the faster it returns the sail to its original position.

Response Time:

Since sails are not totally rigid and are designed to move in a certain predictable way, they therefore depend on the consistent performance of the mast. A sail designed to twist briefly and then return to shape needs a mast that does the same. Put the sail on the 'wrong' mast and it can feel loose, sloppy and uncontrollable. Mast and sail have to match.

There are two measures of stability; how easily does a mast bend and how quickly does it unbend. The ease of bending is measured on the IMCS/MSC system. The speed with which it unbends is largely controlled by the carbon content.

Flexibility:

The right amount of bend and fast response is important, but masts must also bend in the right place. Nowadays, sail designs are generally based on masts having the same graduation of stiffness characteristics along the whole length; the 'constant curve' format. The mast needs to be consistent to ensure a predictable and controllable change of shape.

Carbon Content:

Masts are available in different percentages of carbon ranging from 15% carbon to 100% carbon. No mast is truly 100% carbon, as it contains fibers (carbon, fiberglass or Kevlar) mixed with resin to bond it all together. As a general rule, the higher the carbon content, the lighter the mast will be and the quicker it will respond to return the sail to its optimum position.

So which one do you choose? Good question. In our opinion, a beginner should generally look into either a 30% or a 50% carbon content mast depending on your sail size, your budget and your longterm goals. Let’s look at things a little more into detail as this can be a slightly long winded answer.

Epoxy Masts: Many beginner packages are offered with a fairly cheap epoxy mast. If at all possible you should avoid these. They are heavy and not responsive and not what 99.9% of intermediate windsurfers are using to get the most out of their gear.

10-15% Carbon: Many beginner packages are also offered with these masts. But once again, they are pretty sloppy in terms of performance and not considered a longterm investment. Generally as the individual improves they will quickly see the need to upgrade the mast to a more performant mast. They offer little noticeable improvement over an epoxy mast.

Now is the time that you have to think about what your longterm goals are:

30-35% Carbon: These masts are good on budget and offer more bang for your buck than the first two options. However, your ultimate decision will be made from there.

Let us presume that you have a 6.5m sail.

a) If you plan on eventually purchasing a smaller sail to match up with your 6.5m, then a 30% mast will do you just fine.

b) If you plan on eventually purchasing a bigger sail to match up with your 6.5m, then we would personally recommend a 50-55% carbon mast. Here is why:

50-55% Carbon: Now is where we start to discuss performance in a mast. A 50-55% carbon mast is still reasonable on your budget, but offers better shape, response time and flexibility and lighter weight. This means that your sail will perform more in the way that it was designed to.

In the previous section, we said that it was important to think about your longterm goals. This is because as your sail size increases, the importance of reaction time of the mast increases as well. We consider this carbon content mast a middle of the road type of mast, sort of like all-season tires, if you will. It does everything in most conditions pretty well for the cost; which brings us to :

75% Carbon: You will notice significant differences in the performance of your rig with this carbon content. It gives your rig a lighter feel and decreases the reaction time to make the rig work more efficiently allowing the sailor to sail longer, and maneuver a little easier (depending on your level of expertise).

But are these differences enough to justify the extra money? In our opinion, it is worth the extra money if the extra few hundred dollars won’t break the bank and if your longterm goals justify the expense. The positive aspects of this percentage of carbon are really much more noticeable on bigger sails, so if you are planning on going bigger than 6.5, then this would be the percentage to get.

100% Carbon: We don’t want to go into too much detail about 100% carbon masts as it concerns only a select few sailors who want to eek out that last little bit of performance and weight reduction from their rig. Although they are super-light masts and perform very well, they are pricy and not considered necessary for the beginner to intermediate sailor who is just learning the ropes.

Here is a visual description of what we mean by flexibility and sail shape.

Taken from Boards Magazine June 2003 issue.