Hmmmm...... I had one of those a while back. Never really could get it to fly well due to severe lack of skill. I'm gonna rebuild it and try again soon. It looks like your problem is that the sponsons (front parts that are in the water) are angled out rather than being set flat against the water. They need to be able to push down on the water to lift the "boat" out ov the water, like water skiing. With the angle you have on yours they're wasting that push on shoving the water to the sides rather than straight down.

In short, you want to decrease or get rid of the angle on the sponsons' bottoms.Also,you may want to increase their area a bit.If this doesn't help I'll eat my hat, should I happen to be wearing one at the time ;D Good luck!