In Star Trek IV, Scotty gives away the formula to the inventor of transparent aluminium. This aluminium, if my memory serves me, is to house the humpback whale they must procure from the past. Crazy, I know.
But why does the humpback whale need to be in a transparent container? I know it wouldn't be pleasant, but for the short few hours once they'd stolen it, but is that sufficient enough to justify simplifying your time in the past?
I realise from a previous question that Scotty thought he had to give the formula away, as the man they found was the inventor (Marcus Nichols). But until he found him he didn't seem to know he would find him, so that can't be sufficient reasoning to go looking for transparent aluminium.
Why did they need it?