Should there be concave between keel fins

I have checked out a shapers fish keel fin boards and he puts a fairly noticable concave between the fins, what effect would this have on the board instead of a V.

I would think it would make the board faster. Maybe a bit more drive too.

…I like flat,or with no more than a 1/8" of mono/cupped concave.Too much concave,especially w/ the hump in the middle, between the fins or anywhere else on the bottom, works well going down the line on lively waves,But if it’s slower/smaller common waves,it inhibits the board from being a true skate.Same goes with VEE in a fish.I’ve seen fish with mountain VEE and think to myself ,“there’s a waste of materials”.If it’s a longer fish, a slight vee like 1/8" or less is okay,especially if it’s thick,flat and boxed.Now this is refering to standard twin keel type fishes…Tri-fin,singlesonly type fish have more room to play with,but I generally stick with my first statement.After 30+ years of riding the best and building my own,believe me I know JACKFISH!!!If you decide to go w/ concaves or vee… fade it out starting at the front of the fins and finishing into a flat bottom at the trailing edges OF THE FINS.Herb