Hi Keith,
The death for John HAYES-buried 9 Jul 1851... is surely "yours",though?
I'm not really seeing any confusion. (trying to be careful-but why would your guy be at sea in the first place?

).
Easy answer is the death cert. Maybe this one?
GRO Deaths:
HAYES, JOHN 51
1851 S Quarter in WINCHESTER & HURSLEY Volume 07 Page 175
All the best,
Maureen