"Ach, yes, I believe you I, and that was sorta my point. How is it that we define (my emphasis) extreme conditions such as you describe as temperate?"
Hi Chris. But no, no, no - these are not 'extreme' conditions (!) just typical of Scottish or west coast Irish diving, and I use temperate to describe anything not tropical or sub-tropical (not just Britain/Ireland either). In Britain hard boats such as Offshore 105s (a 10.5m planing hull) are commonly used as dive boats, but also much bigger vessels may be too. The problem is that such vessels operating in coastal waters cannot manoeuvre easily if any tide is running and near shore (especially with divers near) - the only practical way is to go in with the camera. I've never had a problem going in with a camera (except once from a Rib when the housing got smacked by something (and this was of course in good conditions!) provided I took care to protect/shield it as best as I could. The drop from an offshore 105 is about a meter, from bigger boats it can be more.