But at what point did he 'know' the Titanic was doomed, Geoff? Even Wyn Craig Wade, one of the first to criticise him extensively, believes he was answering with absolute sincerity when he said he didn't realise until comparatively late that the ship was going to founder.
I don't know about him being guilt-ridden - the family members I've spoken to certainly didn't indicate it. They described him as a very proactive, forward thinking man, so such tortured introspection doesn't particularly seem in character. One family member said he wasn't inclined to brood over the past. Of course, we can never know what a man feels in his very innermost soul. He himself wrote that it was wise not to dwell on the final moments as the ship went down. He possibly had regrets - I find it hard to imagine that anyone in that situation, no matter what sort of job they did, would not look back at some point and wonder how they could have done better.