Are you sure the line is a floater?

Op's suggestion about water seeping in through cracks in the line is
possible. If it's a poor quality line with cracks over its useful
length then it will sink.

It is also possible that after a few hours use - in a lake - the line
is covered in slime, scum and goo that causes it to sink. In which
case a good clean and treatment should get it up on top again.


Steve