Buy a windsurf mast for RDM and SDM sails
A windsurf mast is the vertical tube that keeps your sail upright and forms the foundation of your complete windsurfing setup. The mast determines how your sail stands, how smoothly it rotates in the wind, and how much weight you carry on the water. Our range includes masts from Severne, STX and NP in carbon percentages from 40% to 100%, in lengths from 340 to 490 cm, for both RDM and SDM sails.
When windsurfing, the mast and sail are inseparable: a mast with the wrong carbon percentage or wrong diameter won't fit your sail and will distort the profile. Below you'll find an overview of the key features.
RDM, SDM, carbon% and use at a glance
| Type | Carbon% | Stiffness (IMCS) | Suitable for | Price range |
|---|---|---|---|---|
| RDM (Reduced Diameter) | 40% | Flexible | Beginners, freeride, waves | Entry level |
| RDM | 60% | Medium | Allround freeride, light wind | Mid range |
| RDM | 75-80% | Stiff | Wave, advanced freeride | Mid-premium |
| RDM | 100% | Very stiff | Wave, competition, light wind | Premium |
| SDM (Standard Diameter) | 40% | Flexible | Freeride, larger sails beginner | Entry level |
| SDM | 60% | Medium | Freeride, slalom entry | Mid range |
| SDM | 75% | Stiff | Slalom, freerace | Mid-premium |
| SDM | 100% | Very stiff | Slalom competition, race | Premium |
Rule of thumb: always check your sail's manual first. The manufacturer specifies a recommended IMCS value. Using a mast with a lower IMCS than recommended causes your sail to luff early and you'll lose power.
Frequently asked questions about windsurf masts
What's the difference between RDM and SDM masts?
RDM stands for Reduced Diameter Mast and has a narrower diameter along its full length. SDM stands for Standard Diameter Mast and is significantly thicker at the bottom than the top. Wave sails and most modern freeride sails from Severne and NP are designed for RDM, while larger freeride and slalom sails typically require an SDM. An RDM mast is more flexible and absorbs wave impacts better, making it popular with wave surfers. An SDM gives larger sails a tighter profile and more power in light wind. Always check your sail's specifications before buying a mast, as some sails are explicitly made for only one type.
What carbon percentage do I need in a mast?
The carbon percentage determines how much carbon fibre is built into the mast. The higher the percentage, the lighter, stiffer and more responsive the mast is. For beginners and recreational freeride surfers, 40-60% carbon is an excellent choice: good stiffness feel, affordable and forgiving on hard impacts. Advanced surfers who want to feel every wind shift go for 75-100% carbon. Competition sailors and racers almost always ride 100% full carbon for maximum responsiveness and minimum weight. Also consider the IMCS recommendation of your sail: a too-soft mast distorts the sail profile and costs you power.
How do I choose the right mast length for my sail?
Every sail has a specific recommended mast length, typically stated as nominal length in centimetres (340, 370, 400, 430, 460 or 490 cm). The mast doesn't need to be exactly that length: with an extension of up to 30-40 cm you can adapt a shorter mast to the required total length. When in doubt, go for the slightly shorter base mast with the corresponding extension: you'll have more flexibility if you later buy a sail with a different mast length. STX C40 and C60 masts from 340 to 490 cm are available in our range as full base lengths.
How do I maintain my windsurf mast?
After every session, rinse the mast thoroughly with fresh water, especially if you've been surfing in salt water. Salt penetrates deep into small cracks and accelerates material fatigue. Dry the mast completely before storage. Regularly inspect the connection between the two mast sections for scratches or cracks; a damaged connection can fail suddenly under high loads. Store the mast horizontally or in a dedicated mast bag, not leaning upright against a wall. Lightly grease the connection with silicone spray so the parts slide in and out smoothly.
In stock? Order before 17:00 and it ships the same day. Otherwise, as soon as possible. Not sure? Our specialists in Joure are happy to help.
