Fishing
Earlier in his life, a student had worked as a commercial fisherman. The student had the idea to return to all the places he had fished with his father as a boy, and then later as an adult, and throw some Mani, Mitukpa, and Namgyalma mantras into the water. Rinpoche’s response was as follows.
That is great. You can carve or write the mantras on a board or in copper, and then tow it behind the boat. Or you can go to a bridge and let it drop into the water while reciting the mantras. Do the same with prayer wheels.
The mantra can be written in Sanskrit on one side of the board, and in Tibetan on the other side. If the boards are thrown into the water they should be made of materials that last as long as possible. If you make prayer wheels to put into the water, you shouldn’t allow any water to get inside of them.
There is a family in Taiwan who live by fishing. They built a circular wall out into the water, across from mainland China, with mantras written above and below the water, and underwater stupas.