Not sure that "conversion" is/was an issue. Don't Americans use pounds? In Australia divers use pounds when it comes to dive weights. I suppose it is possible that Tina didn't recognize that the numbers on the weights were in pounds..which might explain the massive amount of weight but you would think she would have worked it out just trying to get to the entry point. Hmm might lend some credibility to Gabe's reference to her being heavy. Wonder what his BCD lift capacity was..
I didn't know that we all use lbs.
Still, whether she had 18 lbs or..my gosh 38lbs, she was overweighted. My wife dives tropical water in a 5mm (because she just gets cold!), and she uses 12lbs.
I would bet that Tina was wearing a 3/2mm suit. Based on her build, she probably needed no more than 8 to 10lbs of lead. So, she was drastically overweighted. If the 38lbs mentioned is a correct number, then her small women's vest style BCD would not keep her neutrally buoyant at 45 feet. With 18lbs of lead, had she passively panicked and mixed up the inflator/deflator buttons and failed to inflate her BC, she would drop like a rock.
Either way, if Gabe was having trouble maintaining his own control in the water, and being overweighted himself (28lbs), he truly could have been unable to prevent her descent.
Had he had his wits about him, as DandyDon has said, he could have ditched some of her weights, and then helped her control her ascent, but maybe she knocked his mask off and reg out before he could "stop, think, then act."
My original premise was that he was guilty because, if it were me, I'd do ANYTHING to save my wife, my family...and would have found a way to save her or die trying.
Now, I think Gabe tried, but with a lost mask and reg, and being far beyond his comfort zone, he froze. Then he had to live with that. He interviewed poorly and with inconsistency because he either doesn't clearly recall everything, or he is unable to admit how badly he screwed up.
He may have killed her by pressuring her into a situation that neither he nor she could handle, but I don't believe that he murdered her.
He has already been convicted of and served time for manslaughter.