[jabl]

> And your comment is?

Merely expression surprise at your statement, considering my experience is so different. I have no experience of 'luxury' yachts though, just regular sailing boats. So maybe those superyachts are different?

> The fact is that marine engine exhaust systems in good repair are not down-flooding points and certainly not on the yacht in question, where it almost certainly was below the waterline.

Well I agree with that, but because, again in my experience, sailing yacht exhaust systems tend to have an S curve where the exhaust goes relatively high up. Whether the exhaust opening itself is just over or under the waterline doesn't really matter for downflooding.