ChrisCraft flipping

[wpw4]

Can anyone help ? I powered up a Dumas ChrisCraft runabout with a 3p Ammo 36-56 2600kv motor,Castle 120 amp ESC. It draws 50 amps through two 2s2p A123 packs. It is pretty fast (25mph) for the hull and gets on plane very nicely. All data is from an EagleTree data collector. My biggest issue is that it has flipped; well actually slow rolled, and gone turtle twice while powering down into a gentle turn. I can't remember if it flipped in the same rotational direction, it happens too quickly. Is there any experience that would lead one to think a turn fin would solve this problem? ?? Or some other trick?
Pictures of the boat are attached