Windsurfing Masts – Know Your Stiffness

Windsurfing Masts – Know the correct mast for your windsurfing rig. There are many types of masts and they generally come in two types of materials and that is fibreglass and/or carbon fibre. The amount of carbon fibre you have in the mast will depend on the performance that you require. The more carbon you have the more flex and lightness the mast will be making manouvres and waterstarts a load easier. However, the higher the carbon content the more expensive the mast will be possible costing up to £400.

Mast stiffness is based on a  masterracksbd scale called the IMCS or the International Mast Check System which measures the flex within a mast depending on the load and the relative length of the mast. The IMCS scale starts at around 19 which is very flexible while the other end of the scale is 30+ which represents a stiff mast.

Fibreglass masts tend to be stiff but will almost have some carbon content in them to give it some flexibility. Lets take a wave mast for instance which needs to be durable due the impact of the waves and the beach. These masts normally have around 40% carbon content which makes it light as well as durable. High end performance masts which are very light and are used for racing tend to have the highest carbon content as much as 80%. This high carbon content is important for mast control in gusty conditions where it flexes quickly under load and returns to its relative position much quicker than a heavier mast with less carbon fibre.

Lighter masts are also useful for Formula fleet racing where the conditions are often light winds force 3-4 and where dynamic pumping is required to lift the formula board onto the plain. The lighter masts adds a lot of speed, whip and extra power. When you buy your sail, rig manufacturers may recommend the correct mast for that particular sail so you should’nt have to worry about mast stiffness and the IMCS scale. However, in performance windsurfing knowing your stiffness can be a matter of winning or losing the race!

So, when you purchase your rig make sure you have the rigging instructions which will give you the suggested luff (leading edge), mast stiffness and boom length which should be written at the bottom of the sail. This will make tuning your rig a lot easier and hassle free. Then all you have to adjust is the amount of downhaul depending on the conditions, your ability and the style of windsurfing you are about to undertake.

Brian James

Windsurfer and Instructor

Brian James is a advanced windsurf and kayak instructor has been a contributing author for a number of windsurfing websites [] and has written numerous articles on windsurfing. He can be found on the internet at his website:


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