A Royal Navy petty officer caused the death of a junior officer by letting him dive on a full stomach in breach of safety rules, a court has heard.
Anthony Watt denies manslaughter charges over the diver's death
Lieutenant Paul McAulay, 27, choked on his own vomit under water 20 minutes after eating his evening meal while on a Navy diving course.
His instructor Anthony Watt, 41, of Roundway, Waterlooville, Hants, denies manslaughter due to gross negligence.
Lt McAulay, of Clackmananshire, died at Horsea Lake, Portsmouth, in 2002.
Mr Watt also denies a health and safety charge of failing to take reasonable care of his student.
Jonathan Fuller QC, prosecuting, told Winchester Crown Court that Mr Watt had failed to adhere to safety guidelines barring diving for two hours after a heavy meal.
Mr Watt also failed to have a person in diving kit ready to help Lt McAulay when it became apparent he was in trouble.
The delay of seven minutes while a diver was summoned from the shore made matters worse, jurors heard.
Lt McAulay, who was married, was the Navy's bobsleigh champion.
He was on day nine of a 20-day course on 28 November 2002, when he was called back to a classroom after dark, after eating a heavy meal.
The court heard that within as little as 10 to 15 minutes, the young officer was outside in the training lake, dressed in a dry suit, face mask and snorkel, trying to retrieve a marker at a depth of six metres.
Lt McAulay made two attempts from an inflatable boat to reach the marker by holding his breath, before making the fatal third attempt.
Mr Fuller said: "The consequence of his exertions was that he vomited. He inhaled the vomit into his windpipe and his upper airway and he struggled for breath."
Lt McAulay was unconscious in seconds, suffered a heart attack and sank to the bottom of the lake.
The trial is expected to last four weeks.