I think "The Neptune Society" has the best idea. Mix the ashes with concrete, and move it offshore to build a natural reef. My Dad was in the Navy, and after his funeral, I got a brochure mailed to me. Perhaps it's "Navy" that desires that kind of connection.
Personally, I'd like to skip the "cremated" part. It uses a lot of energy, and folks who live nearby have "issues" with the facility!