Windsurf Mast Guide
Introduction Wind Surf Masts
Windsurfing, the fascination of holding the power of the wind in your own hands. It is enjoyment, nature experience, training and sometimes great challenge.
To make sure that the challenge is not too great, especially when you are just starting out, we have put together a small guide for the suitable material.
IMCS
The IMCS value, denotes the hardness of a mast. In simplified terms, a 30kg weight is hung in the middle of a mast and then the deflection is measured.
As you can imagine, this measurement says very little about the exact way in which the mast bends in the course. Therefore, the importance of this old measurement method has decreased.
| Mast Length | IMCS value |
|---|---|
| 340 | 15 |
| 370 | 17 |
| 400 | 19 |
| 430 | 21 |
| 460 | 25 |
| 490 | 28 |
| 520 | 32 |
The entire industry has agreed on these mast hardnesses.
Bend Curve
The much more sensible measured value, is the bending curve at which, at several points of the mast either after 1/4, 2/4, 3/4, or with another method also at 5 measuring points the bending is measured.
In this area, 3 main bending curves have emerged:
| Bending curve: | Characteristic: |
|---|---|
| Hardtop | Bends a little more in the base in relation to the Constant Curve and a little less in the top. |
| Constant Curve | The middle bending curve where, as with all others, the base bends less than the top. |
| Flex Top | Bends more clearly in the top than the Constant Curve, but somewhat less in the base. |
Some manufacturers also still deviate slightly from these bending curves.
Overall, you will find even among the 3 labels still small differences in the masts. The safest choice is always to use a matching mast , of the same manufacturer, from the same year to the sail.
The mast manufacturer Unifiber measures every year the current masts of the major manufacturers and publishes a table if you would like to get more accurate information, about the compatibility.
Carbon share
Today there are usually masts with 25-100% carbon content.
The higher the carbon content, the higher the price. A mast under 50% is actually exclusively for the beginner who is looking for a start as cheaply as possible. 50% is the cheapest riser variant that makes sense.
Masts around 70-80% carbon content represent the golden mean, between price / performance. The differences from 50-75% carbon are most 100-150€. The performance jump is relatively large. If you want to increase the performance beyond that, you pay more and more money up to the 100% mast, for a smaller increase in performance.
The higher the carbon content, the higher the reactivity of the pole.
This means that a sail regains its ideal shape more quickly after a mast deformation, e.g. due to a gust. As a result, it remains more controllable, the pressure point wanders less and overall it also feels more neutral.
Mast
diameter
RDM: The Reduced Diameter Mast
has been used in recent years for sails, up to about 6.5sqm and masts up to a length of 430cm. The Rdm mast has a diameter of 32mm and a thicker wall than an SDM mast. It offers considerable handling advantages for smaller sails.
The rigging is also easier due to the easier threading into the mast pocket. In addition, the thin diameter also has a smaller mast pocket and thus makes more neutral sails with less belly possible.
SDM: The SDM Masts
were the market standard until around the turn of the millennium. Today they are only used in large sails from 7.0 sqm and up. The reason why the advantages of RDM masts in large sizes no longer prevail is the greater wall thickness of the Rdm masts, which leads to a higher weight.
Another reason is that the profiles of large sails tend to be very bulbous, a thicker mast, simply fills the mast pocket cut wide for a deep profile better, so you get a more stable and powerful overall profile.
All in all, all you really have to do is remember,
that you should in any case go for the RDM mast for sails under 6.0 sqm, above that you have the choice with some manufacturers up to 7.5 sqm to design with the RDM mast more for handling, or with SDM more for propulsion.