Michael McFadyen, another diving expert who has examined this case and was prepared to testify for the defense, agreed. He said he wouldn't take Tina Watson or any diver with her lack of experience on the Yongala dive.
"She's never been [scuba diving] in the ocean, never been in salt water, never been in a place where there's wave actions, currents," he said.
Edmonds and McFadyen said the first three to four minutes of Tina Watson's dive were normal, as she and her husband leisurely followed the anchor line down 30 feet to the Yongala wreck.
It was in the fifth minute, when they let go of the anchor line and Tina Watson began to sink involuntarily, that the touble began.
"[Sinking this way] makes you very unsettled," McFadyen said. "It also makes you swim in a vertical situation instead of being horizontal, like you should ... which takes a lot more effort."
Edmonds said that Tina Watson's motioning back to the anchor line was "sensible, except it doesn't take into account the effect of the current. ... Had they got back to the line, it would have worked. Unfortunately, they only got halfway back."
"Because she was over-weighted, because she was swimming against a current, she's exerting herself greatly," Edmonds said. "And we know that, because of her air consumption, which was unbelievably high, she was also panicking."
Panicking made her overbreathe, then aspirate water through the regulator in her mouth, eventually losing consciousness and sinking to the ocean floor, Edmonds said.
"The autopsy was very clear," Edmonds said. "The findings were that she [was] drowning and that she had air embolism. ... If you look at the statistics on diving fatalities, the two commonest causes of death are drowning -- in about 70% -- and air embolism -- in about 14%."
The prosecution said Gabe Watson didn't ascend as quickly as he might have, and that this showed his intent to kill his wife.
"I happen to think that he went up quicker than they think he did," McFadyen said, "mainly because they're relying on the ... the graph that's produced by the dive computer as being 100% accurate, and it's not."
Dive computers take snapshots of a dive based on each time a diver goes through a 10-foot level, McFadyen said. "So if you go through at two minutes 10 seconds, it would record it as two minutes. If you went through at two minutes 59 seconds, it would still record it as two minutes. So it's not exact."
Because of this, McFadyen believes Gabe Watson ascended the 54 feet in about one minute 30 seconds, an ascent he characterized as "quick."