How fast were you reeling in the rat? From the looks of the angle of the bill, when reeled in slowly, should just create a wake and not dive down. Im in the process of testing out a rat I built but I used circuit board as a bill. I have another build where the bill was just straight and not at an angle and created a very nice wake at a slow- medium retrieve so I did the same with the bill on my rat build. I'm hoping for the same effect with this then again the bill I used on the rat is much smaller! I believe if the bill has a slight angle it will cut into the water creating the lire to dive down where if it's straight up and down with no angle, it keeps the lure on top creating that "wake," effect! Hope this helps and I'll let you know how my lure swims when I get a chance to go out!