My informant told me of an old Irish superstition that he learned from his father:
“If you bless yourself before diving into the water, it keeps you from drowning”
My informant swims often, and he said that he always blesses himself before going into the water. He does not remember a time when he didn’t, and believes that he would surely drown if he did not.
I have seen my Irish relatives make similar gestures before doing things like: crossing the street, getting on an airplane, or even carving the Thanksgiving turkey, so it did not surprise me that crossing or “blessing” yourself before diving into water was also practiced. It again highlights the strong connection between the Irish and religion, and the fear that comes along with it. In this case, the fear is drowning.