Concave is simply the channelled slots which run on the slick side of a bodyboard at the tail end of the board. Achannel on the tail end of the bodyboard allows the rider to maximise their control over the board. The slots on each side of the board redirect waterflow and offer the rider lift in the tail. Being able to manipulate the waterflow and create lift allows the rider to get a better grip on the wave. Once the rider has good grip on the face of the wave they can gain and reduce their speed, traverse sections, do manoeuvres and control their---- movements. Slotted channels were introduced some years ago now and you won’t find many boards without them now. They’ve retained their place as one of if not the most valuable and meaningful aspect of the board. The importance of the concave has by all means been noted in more recent years and has led to the initiative which are the new range of multi-concave bodyboards. Having more than a dual concave on the bottom of your board will add additional tracking for waterflow as well as expelling it for maximum speed. Most Multi-Concave bodyboards will use four final concaves. The two inner concaves on the bodyboard run within the confines of the your central hull and aid in maximising central waterflow. This offers the rider a central waterflow and more power in both the high line and bottom turns. The outer concaves, normally closer to the rail side of your bodyboard, draw water the full length of the outer rail which creates a much more power driven and focused bottom turn as the water has to pass the full length of the board. Atop of all this these Multi-Concave bodyboards offer a little bit more lift off of the tail. Although it wasn’t an intended feature of these boards most riders will note that the board paddles in to waves easier and also releases easier in terms of spins in and out of the pocket.