Budget?
for about £20 you could get a nice Solarforce L2R + dropin, which will happily run on AA's at a respectable brightness.
for about £35 you could get something like an iTP SA2 Eluma
For £40 you could get a nice Jetbeam BA20
and for £60 you could get a Sunwayman M20A
if you're willing to step away from the 2xAA format (which, if you're at sea, you probably should) then 2xCR123A lights will offer higher potential output as well as longer runtimes (considerably longer in the cold) at the cost of lesser convenience and higher running costs.