trinity-holloway documents

I m a bird. I can fly.I m big and hard. I dont eat. What am I? I live in the sea. I can swim very fast. But I m not a fish.I m a traffic tool.Please
Documents I m a bird. I can fly.I m big and hard. I dont eat. What am I? I live in the sea. I can swim very fast. But I m not a fish.I m a traffic tool.Please