never had them for marine, but i have one in the old chevelle, and well it had been sitting for over 2 years, in the car, and it started the car first turn, was surprised there was any juice left in it, and that the car started... wish i had more time for the old car...
i dont think you will see a regular battery do that.. here is the battery companys sales pitch or one of them, link on bottom..
Delivers higher peak amps faster than conventional batteries
Provides up to twice the life of conventional batteries
More consistent voltage across the discharge curve
Superior cold and hot weather performance vs. conventional batteries
Available in models with SAE posts, stainless threaded studs, or both
Spill-proof, even if the case is physically ruptured
Will not off-gas in normal operation, eliminating fumes, odor & corrosion
Over 14x more shock and vibration resistant than conventional batteries
Provides more power from a smaller package
True zero maintenance
Holds charge better during periods of nonuse
Operates in any position without spilling
Offers proven durability & performance (Read testimonials)http://www.1st-optima-batteries.com/