My parents loved cruising and loved the Pacific. We mixed 1/2 of each of their ashes together, acquired a biodegradable urn etc. as stated above. Contacted RCCL and made arrangements before hand.
Told TSA authorities when entering airport security, told screeners at Port. Talked with officers on ship. Off coast of Mexico we were told to go to a lower deck and at rear with officer. We all went out of little balcony, said some prayers, etc. and tossed packet overboard. At time I tossed it the officer keyed his walkie talkie and said something. Later on we were presented with certificate and coastal map showing coordinates of where my parents ashes were tossed into the Pacific. Hong Kong was their favorite city and if we ever get there we will spread the remaining ashes.