Wow... My story is similar to so many others...
Years ago I saw this on TV. Would have been 1978 I guess since it was a made for TV movie.
The scene that stuck out most for me was the scene where buddy got dragged underwater by the turtle.
About 15 years ago, I tried to find out what the movie was. It was only today that I thought about it again and I wound up here after searching "movie where man gets dragged underwater by a turtle".
Gonna watch this again and see if it still freaks me out as much.
+++ Jason