Lt. Brad Snyder has already proven his dominance in the water, earning three medals at the 2012 Paralympics in London. Now he’s looking to show that being blind won’t hold him back on land or a surfboard either. On May 19, Snyder is participating in the Trident Challenge — a 5K run, 500-meter ocean swim, and 1.5K ocean surfboard paddle — as part of the Never Quit weekend in Jacksonville Beach, Fla. He will be guided in the run and the paddle by Bethany Hamilton, a surfer who lost one arm in a shark attack. Snyder, a former explosive ordnance…