Did I drown him???

Question
I picked up a turtle that had been clipped by a car...(I believe he was a box turtle, although I can find no pictures of one exactly like him online. He was very round, bowl shaped with knots on his shell, a black head and neck, not a strong pointed nose but not square either, about 6 toes, scaley legs) anyway he had a crack in his shell about 2 inches long and was bleeding. I took him home, cleaned the wound with providine iodine, and kept him in my bath tub for 3 days. The bleeding had stopped and the crack turned a white-ish color. So, I took him outside and he seemed raring to go. Was crusing all over my yard. Anyway, there is a pond close to my house, and I decided to take him there. And he went right into the water, but just kind-of floated and made no attempt to swim. So, I reached in and took him out of the water and put him back in the grass, but he went right into the pond again. And again, he just floated. Thinking he knew better then I, I left him there. ...anyway, by the time I got home, the thought of him "floating" like that really started to bother me, so I went back to the pond and searched for him desperately but to no avail. The pond is about 1/8 of an acre in size. Researching online - which I should have done first...I read box turtles cannot swim and will drown!! Oh my god...did I drown him?

Answer
'Knots' on the back of the shell and other parts of the description sound more like one of the mud or musk turtles than a box turtle- and they swim just fine.

Box Turtles don't drown easily, if it was a box, and can do a form of dog paddle nicely and can float for a while. Unless you chucked it into the middle of the pond, it would have been fine. Besides, it sounds like it CHOSE the water- a very non-box turtle thing to do.

If you run across another injured turtle, help it out by moving to a safe place in the rough direction it seems to be heading- they actually usually do better on their own- but I am always glad that there are people who try to help!

Good luck!

By the way, try googling "(your state) turtle" to see photos of what lives in your area- you might find it!