In dreams, Carl Jung wrote, the sea is a symbol of our Collective unconscious, "because unfathomed depths lie concealed beneath its reflecting surface." When you cross the sea you do not know what lies under you; you cannot see where you are going or where you came from. The sea represents the unknown and the unknowable; the sea represents mystery.
Water and the sea can be symbols for many things. In Hemingway's The Old Man and the Sea, the ocean is a woman to be loved and honored but also "something that gave or withheld great favours." The sea is the original source of life and continuing source of food, a parent, yet it offers no guarantees or compassion. The sea grants and then takes away Santiago's prize.
In Christian baptism, going down into the water symbolizes death. Walking on water is the test set by Jesus of Peter's faith and trust. At least Peter tried.
Perhaps this man is waiting for Charon the ferryman to take him across to Hades? The rings might be used to chain reluctant passengers but this man is not tied, he will not run.
You can read your own story from this picture. I choose to see a man on the edge of the unknown, aware of both beauty and danger but trusting the beauty more. A man taking a moment to think back over his life before continuing on the road forward, with Van Morrison, Into the Mystic.