The DRIFT STOPPER is adjustable in length. "Out of the box” the shortest setting is 76 cm - the longest setting is 80 cm. Since your board width is just 70 cm you would need to cut down the DRIFT STOPPER. The design allows for this but it requires handy-man abilities. Also when using a 70 cm wide SUP for Windsurfing it is quite hard to keep the balance - at least for a beginner. In summery yes it’s doable but not really ideal.