Double concave's are usually used in dropknee board's instead of channel's. These are shaped using the artificial intelligence of the AKU machine to precisely create a double convave bottom to capture the laminar water flow, creating a faster & more stable bottom contour.
The double concave hull features 2 concaves on either side of the hull which splits the water flow into double Channels, createing an air pocket in the back half of the board. Breaking up surface tension & creating an air bubble resulting in more lift, less drag, increased speed while having better hold & rail control resulting in better manouvreability. This creates the ultimate board for speed & control.
The "v" through the middle helps with control, particularly when transitioning from rail to rail.