Estate planning after a sea ceremony involves one task that land-based burials handle automatically: recording where the person rests. A cemetery plot is a deed, a file, a maintained record. A release point in open ocean is a GPS coordinate on a signed certificate — meaningful and specific, but only as permanent as the family makes it.
The GPS coordinates certificate issued by the captain should be treated as an estate document. It belongs with the death certificate, the disposition permit, and the will. If you use a fireproof document safe, it goes there. If your estate documents are held with an attorney, provide a copy. If you store originals in a safe deposit box, make a digital scan and store it in a secure location — cloud storage with documented access, or on a drive held by an executor.
Consider noting the burial location in the will or trust itself — not as a legal requirement, but as a record that survives beyond any individual's memory. "The cremated remains of [name] were scattered at sea on [date] at the coordinates recorded in the attached GPS certificate" takes three lines and ensures that future generations who discover the estate documents have complete information. Executors, adult children, and grandchildren who never attended the ceremony will know.
Some families include the burial location — or a reference to it — in the obituary, a memorial book, or a family archive. The coordinates themselves may be too technical for a general obituary, but "interred at sea off the coast of San Diego" or "her ashes rest in the Pacific west of Point Loma" conveys the essential information in a form the public record preserves.
Future generations will want to know. Children grow up, have children of their own, and eventually seek their ancestors. A recorded burial location — even in open ocean — gives the search a destination. The sea is specific. The coordinates are knowable. Make sure they survive.