Hamptons Luxury Developer Faces Felony Charges After High Speed Sag Harbor Boat Crash

The prominent builder, known for multimillion-dollar estates across the Hamptons, now faces felony charges after a Fourth of July weekend boating crash left several passengers seriously injured.

Things tend to get lively in the Hamptons during the Fourth of July, but no one expected this. On a hazy holiday weekend when the Sag Harbor docks typically glow with the lights of yachts, local luxury developer Peter Mangiameli found himself at the center of a very public wreck — literally.

Mangiameli, better known for the kind of oceanfront estates with infinity pools and tennis courts that make brokers swoon, was behind the wheel of his 35-foot powerboat near the mouth of Sag Harbor Bay. He had eight passengers on board, heading home from Shelter Island, when, according to investigators, he gunned it a little too hard. The boat slammed into the breakwater jetty, that hulking cement wall marking the marina’s edge, and the impact was brutal. Several passengers were thrown around the boat with force.

One ended up with a shattered femur that needed emergency surgery. Another suffered broken ribs. Some blacked out. Rescue crews scrambled to pull injured guests from the chaos while night traffic at the dock slowed to gawk at what might just be the year’s biggest Hamptons boating disaster.

Mangiameli’s work dots Sagaponack, Sag Harbor, and Water Mill with homes famous for their resort-vacation setups and sky-high price tags, with some north of $20 million. He’s a known quantity in East End real estate, and over the years, people have grown used to seeing his name pop up in connection with yet another glossy compound.

After the boat limped back to the dock, things got messier. Cops say they found a handful of battered guests and, notably, no Mangiameli — he’d already left, according to prosecutors, only turning himself in the next morning.

Now, Mangiameli’s facing a neat stack of charges: two felonies, including second-degree assault for the mangled leg and failure to report the accident, plus a misdemeanor assault charge tied to another passenger’s injuries. At his arraignment, he walked out without having to post bail.

The East End, predictably, is abuzz. Everyone seems to know someone who knows someone who was there — or who’s thinking twice before stepping onto any speedboat after sunset. If there’s a lesson in all this, it’s impossible to miss: the Hamptons’ champagne-and-fireworks boat scene can turn on a dime, and even the guys who build the dream houses aren’t immune when trouble comes barreling across the bay.