MIAMI — A man whose wife disappeared while they honeymooned at sea was sentenced by a federal judge to eight years in prison for involuntary manslaughter.

Lewis Bennett, 42, apologized to the family of Isabella Hellman during a Tuesday hearing before U.S. District Judge Federico Moreno in Miami. He waived his right to appeal.

Defense attorneys sought a 7-year sentence, a year lower than the maximum number spelled out in a plea agreement reached last November. Bennett was originally charged with murder, with investigators alleging he intentionally tried to sink the boat, but later dropped the charges.

"It's not because I expect that he will commit this crime again," Judge Moreno said. "Sentencing is for punishment."

Lewis Bennett killed his wife, Isabella Hellmann, while on their honeymoon at sea in 2017. Broward Sheriff?s Office

Before Moreno announced his decision, Bennett, a dual citizen of Australia and the United Kingdom, asked the judge that he let him get out of prison sooner so he could continue to raise the couple's daughter, who was an infant when the mother vanished. Emelia Bennett turns 3 in July and is being raised by his parents in Scotland.

"If you may permit me to be with my daughter as soon as possible," Bennett said. "I want to bring her up in a manner that is respectful to my wife's wishes."

But Moreno sided with prosecutors and chose eight years in prison as the sentence and three years on supervised release.

Hellman disappeared as the couple sailed off the Bahamas in May 2017.

A statement from the U.S. Attorney's office says Bennett had experience sailing, including training on emergency procedures and had previously traveled from St. Marteen to Australia. His wife, a naturalized U.S. citizen born in Cuba, had not trained in emergency sailing procedures and had less experience, prosecutors said.

The couple had been married for three months when they set sail to St. Marteen, Puerto Rico and Cuba for a delayed honeymoon in late April. After they left Cuba on May 14, Bennett asked Hellman take over control of the boat for the night so he could go rest in the boat's cabin, according to court documents. He didn't require her to wear a life jacket, harness or personal locator, prosecutors said in the statement.

He said he woke up when the craft hit something, and Hellman was missing.

Assistant U.S. attorney Kurt Lunkenheimer said on Tuesday that Bennett "did not search for her diligently enough despite him being an experienced sailor."

The government maintained he didn't use the satellite phone to call for help. Instead, he loaded provisions and stolen silver coins onto a life raft and boarded it. Prosecutors said he called for help 45 minutes after he had woken up realizing his wife was gone.

A U.S. Coast Guard helicopter rescued him and flew him to the Florida Keys. Authorities searched for Hellman for four days, but never found her body. A Florida state judge declared Hellman dead earlier this month to clear the way for the couple's daughter to inherit her mother's estate.

"Hellman's death occurred as a result of Bennett's knowledge of circumstances that existed that could have reasonably enabled him to foresee threat to life," said the U.S. Attorney's office statement Tuesday.

The FBI said an inspection found that holes in the hull were inflicted from the inside and hatches were opened in a deliberate attempt to sink the boat.

Bennett was initially arrested and charged with murder last year before reaching a plea deal with federal prosecutors. He had already pleaded guilty to transporting $100,000 in stolen coins.

The defense attorney declined to comment. An attorney for Hellman's family said her relatives were satisfied with the judge's decisions and were excited they would soon be able to visit Emelia in Scotland.

"There is nothing that can or could be done to bring Isabella back," said Mitchell Kitroser, a lawyer who spoke on behalf of the Hellman's family and said they were planning a visit in June. Emelia "lost her mom but that doesn't mean that she has lost her mom's family."

An earlier version of this report had an incorrect age for Lewis Bennett.