OK, I was out of town, and unable to browse the forum.

Glad somebody spotted that there was no engine.
You also need a WING. It's a primary consideration in becoming airborne.

Just as an experiment, try sharpening the back of the step of the floats. GeeBees are limited by the manufacturing process in how sharp they can be . Maybe some epoxy on the back of the step, and sand it flush with the bottom in front of the step. Or, re-skin the bottom of the front half of the floats with some really thin plywood and PFM.

Don't horse back on the stick when you're trying to take off, just a tiny bit of back pressure after you get up on step. If the backs of the floats dig in, it's just like dropping anchor.