Better rope and it appears you are crossing lines by not using the correct method for when the pulleys of the sail and extension are 90 deg to each other (as mentioned by those above)
It seems it's intended to be used as a two pulley system
boardsportscalifornia.com/product/2025-duotone-now/
"
TACK ROLLER 2.0During the development of the TACK ROLLER 2.0 we've measured the downhaul forces on all kind of sails. We've found out these interesting facts:1. When downhauling a cambered slalom sail the forces necessary are nearly 3 times as high as when downhauling a no-cam (wave) sail (160 kg vs. 60kg)
2. With a 6:1 power-ratio you need to pull twice as much rope-length as with a 4:1 ratio. Therefore, with a 4:1 ratio you can downhaul the sail in one go, whereas with a 6:1 ratio you always need to retighten the rope.
3. Threading the rope through all rollers (without the rope getting crossed) takes at least 4 times as long as just looping the rope.
4. In theory with a 6:1 power-ratio the downhaul forces should only be half as high compared to a 4:1 ratio. In real life though the friction loss at each roller reduces the downhaul tension by only 15% at most (wave sail: 57 kg vs. 60 kg / slalom camber sail: 135 kg vs. 160 kg). Therefore, we've designed 2 versions of the TACK ROLLER 2.0:
>> NOCAM Version used on all no-cam sails The massive comfort and speed advantages of the 4:1 ratio (Loop-Loop-Go) outweigh the very slightly reduced downhaul forces of the 6:1 ratio.
This version features 2 nickel plated brass rollers at the outside plus a center spacer featuring a bigger diameter. This ensures that the rope loop automatically slips into the 2 outside rollers.
>> CAM Version used on all cambered sails The downhaul forces are so massive that even a small reduction helps.
The 3rd slightly bigger roller allows to either use the 4:1 (Loop-Loop) or the 6:1 (Thread-Through) option."