Perhaps you could also add these Danish admirals too -
Herluf Trolle - 1516-1565
Christen Thomesen Sehested - 1664-1736
Steen Andersen Bille - 1751-1833 (81 years old)
Also, I know he's a bit outside the time frame, but the Austrian Wilhelm von Tegetthoff, 1827-1871 (43 years old), really deserves a mention as one of the greatest admirals of the 19th century.
Perhaps you could also add Willem Joseph van Ghent (1626-1672) for the Netherlands.