Jim Piazza has been fishing off the Jersey Shore for years, and he’s seen plenty of small sharks and reeled in a few sand sharks in his time on the water. On Saturday, though, he got uncomfortably close to a monster — a great white shark less than a mile off the coast of Sea Isle City. He estimated the shark was about 12 feet long as it sidled up to his boat. “The videos don’t do it justice,” Piazza said Monday. “It was just nonchalantly there.” Piazza, of Media, Pennsylvania, is renting a home in Sea Isle’s Townsends Inlet neighborhood this summer. He had been fishing all morning with his son…