I read, ages ago that the actor who played him ad-libbed the line,and it made cameron laugh so he kept in it. But thats probably just one of those rumours!!!
I highly doubt that an actor would come up with such a sophisticated bit of dialogue, but I suppose stranger things have happened. If you listen to Cameron's commentary on the DVD, he credits to aforementioned writer for that line. Rumor put to rest, it came from the horses mouth. Um, also, the actor who played whom?
That very true!!! Sorry, the actor that played Bruce Ismay. Damn my vagueness!!!