In 2000, I was stationed aboard the USS Stump (quit laughing) in Norfolk, VA. We used Optimas in our RHIB (rigid hull inflatable boat) Well, some moron tied it up between the ship and the pier, and the wind got bad that night...
So we smashed the RHIB up pretty good. Two Optimas sat under water (SALT water) for 3 days until the wind died down enough to un-wedge the RHIB. Then they got a crane to get the boat out.
The electricians took the two batteries and put them in the back corner of their shop, and forgot about them.
2004, the ship was Decommissioning. I was in the electricians shop when they were emptying it out. They found the two batteries, and one bozo decided to 'test' the battery with a screwdriver!!
So after the flash and the red hot screwdriver, I asked what they were going to do with them- throw them away was the answer. So I took them and put one in my truck and the other in my old School bus.
To this day, I can leave the bus sit for months and go out and fire it right up, even if I have to crank it for 10min just to get the fuel back up through the 20ft of lines.
Same thing with my old truck.
Long story short, I am sold on them and will buy them from now on when any of my batteries die.
You could get a set of marine battery straps and mount them to the batt. tray.