Not sure when civil burials at sea were allowed - there are only three designated areas in the UK for such a burial. They are (1) off The Needles, Isle of Wight; (2) between Hastings and Newhaven and (3) off Tynemouth, North Tyneside.
Have you found his civil death registration?
If he was buried at sea, there may have been a report in a local newspaper to where he lived.
As rosie99 posted, if you post his details, there are many members who would be keen to do some digging.