Does he like me...or is it my imagination?

On Saturday me and some friends went to the beach. The water was really rough, so we couldn't swim or get in the water. But there is a little lake right beside the beach, and so we went to swim & kayak in it instead. The guy that I have liked for the past year, knows that I really like him. Anyways me, him and one of my girl friends were swimming in the lake, and he grabs my hand. I was really shocked. So I said his name and was like "What are you doin? "U know that's my hand, right?" He's like "Yeah, I know, i'm holdin it for safety reasons"... I was like "ok"...Then he held onto it for like another 2 minutes, and then let go. What is that suppose to mean? Safety reasons? Maybe he didn't want me to drown or he was being sarcastic or maybe he was making up an excuse. I don't know what to think. I thought that if he liked me, he would have asked me out by now...what do u think is going on?