A New Jersey grandfather was drunk when he crashed his boat during a 9pm ride and killed his two young grandchildren, according to prosecutors.

Stephen Schneider, 64, was arrested and charged with reckless vessel homicide Friday, almost a month after the July 19 tragedy in Barnegat Bay that killed his granddaughter Mya Golabek, nine, and her seven-year-old brother Sigmund.

The victims were the only children of Schneider's daughter Jennifer Golabek and her husband Sigmund Golabek Sr, both 45.  

Schneider allegedly operated a 30-foot Tidewater Custom 280 boat while intoxicated and struck a channel marker in Barnegat Bay near his $1 million waterfront home last month.

The crash hurled Mya and Sigmund into the water. 

Schneider and his wife, Laurie Schneider, 64, desperately pulled the children back aboard but officials in the Garden State said they were unresponsive.

The youngsters were later pronounced dead. It is unclear if their parents were with them on board at the time of the crash. 

Schneider is being held at Ocean County Jail without bond. His next court appearance has not been scheduled.

The youngsters were described as being 'fun-loving' and 'adventurous'.

Mya's obituary said: 'Mya Bella Golabek entered this world and brought a light that touched everyone around her.

'In her nine beautiful years, she filled the lives of her family and friends with love, laughter, and unforgettable memories.'

It went on to describe her as 'sweet, fun-loving' who had a 'beautiful smile, kind heart, and joyful personality'.

Sigmund's obituary added: 'His sweet smile, gentle heart, and playful spirit brought happiness to everyone around him.'

It added: 'Although Siggy’s time here was much too short, the love he gave and the memories he created will remain forever.

'He will be deeply missed by his family, friends, teammates, and all who were blessed to know him.

'A sibling bond is a love that lasts forever. Mya and Siggy were not only brother and sister, but best friends who shared laughter, adventures, and countless memories.

'Now they continue their journey together, hand in hand, carrying their love beyond this world and leaving behind a beautiful reminder of the unbreakable bond they shared.'

Sources told Jersey Shore Online that prior to getting on the boat, the family had been at MJ's Restaurant Bar and Grill.

The children were taken to hospital following the crash, where they were pronounced dead.

The Daily Mail contacted the Berkeley Township Police and the Ocean County Prosecutor's Office for comment.