Good eyes Chris , I thought that was something just to the other side of the hull .
Now .. the airfoil , COULD be good , OR , could be bad . Try it with and go with it ... see how she performs and take it from there .
If she seems to stay too wet and rides hard on the water , then , I would remove it ... but , if she gets on plane , has a good ride attitude , then leave well enough along .
I will say ... that the DUMAS's seemed to have MANY problems with ride attitude and with a LOT of "messing" with , they could be a GOOD hull . Now , it is very possible , that the fellow how put that there , messed around enough to where the foil is beneficial , rather than a hinderance . ( or for looks )