Trying to remember an anime... help?

[Vance]

I remember a long long time ago, back when I was like 5, there was this anime movie I absolutely loved. I think it was called Starvengers, although I'm not really sure. There were three giant robots, a red one, a blue one, and a yellow one. The yellow one was fat and tough and the blue one was all slender and stuff... I remember the first fight scene took place in the rain, and their base was like an observatory. It's been so long...

Anyone know what this was? It's been bugging me for a long time, and I just realized it was the first anime I ever saw. I also remember there was this scene where they were assaulting this base out in the middle of a body of water and the yellow robot went under the water, grew tank treads, and started ramming the base of the fortress.