Burals at sea where not common. In 20 years I witnessed 2 and 3 scatterings of ashes. One of them very embarrasing!
If the death has occured on board, then is an autopsy required, by the relevant authority? If the ships Doctor is certain of the cause of death then he may issue a death certificate and with the approval of the authorities then burial at sea may take place. Are suspicious circumstances involved?
Families wishes must also be taken into account.
If it is decided that a burial at sea is to take place then the body is prepared and and wrapped into "Burial Canvas", I kid you not, it is special stuff, with the traditional "last stitch" going through the nose, package is suitably weighted. Encanvassment is usually done by the Bosuns Mate assisted by any Cadets..."for experience" Yes Idid it!
Burial usually takes place from a forward car door on 4 deck. During the service the Captain gives the order to "Stop Engines" Engine room has already been slowing down. Props are stopped, body committed and Full speed ahead given. Remember, that on a steam ship and a diesel for that matter,,,this costs an awful lot of money! Far more difficult on a steam turbine because, except in case of an emergency you cannot go from 28 knots to stop in a heartbeat without damage occuring, at the very least lifting safety valves....worst case warping turbines! Diesel electric totally different.
During scattering of ashes what would happen is that the ER would be given a verbal order to ignore telegraphs. Telegraphs would be put to stop, noted in ships log, engines stopped for interment of Mr. whoever, position noted, ER would ignore telegraphs, ashes would be scattered, telegraphs would be put
to full ahead, verbal order would be given to ER to obey telegraphs and all up to Captains Cabin for drinkies!