Sir Ernest Shackleton testified at the British Inquiry. He believed the closer the observer is to the waterline the easier it would be to detect the icebergs / bumps on the horizon.
Q - If I follow you correctly your view is, it is better on a clear night passing through an ice region to have a man as near the waterline as possible?
A - Yes.
Q - That would rather suggest that your view would be that you could detect bergs of that kind better at the stem than you could at the crow’s-nest?
A - Better, the nearer you are to the waterline. When we navigated in thick or hazy weather there was always one man on the look-out and one man as near the deck line as possible.
Q - That is thick or hazy weather?
A - Yes, that is thick or hazy weather, or even clear just the same.
Q - Suppose you had two men in the crow’s-nest, and it was a clear night, and you were going through a region in which ice had been reported, would you put any person in the bow for a look-out?
A - I would put a look-out man in the bow or as near to the waterline as possible, even on a clear night, but I would only have one man in the crow’s-nest.
Q - Your idea would be that of the two men when coming into an ice region, one should go to the bow and one be in the crow’s-nest?
A - My main reason for saying one man in the crow’s-nest is that I think one man gives more attention to the work in hand than two men.
Q - How far would you see one of these dark bergs on a clear night, assuming it to be 60 to 80 feet high?
A - It might be only three miles, depending on the night and depending almost entirely on the condition of the sea at the time. With a dead calm sea there is no sign at all to give you any indication that there is anything there. If you first see the breaking sea at all, then you look for the rest and you generally see it. That is on the waterline. I do not say very high, because from a height it is not so easily seen; it blends with the ocean if you are looking down at an angle like that. If you are on the sea level it may loom up.
Q - You would slow down?
A - I would slow down, yes.
Q - What was the speed of the boat you were in?
A - She was only six knots at full speed. She was 40 years old.
Q - Do you mean to say that you slowed down a vessel of six knots?
A - Yes, I always did.
Q - And supposing you were going 21 to 22 knots. I suppose that would be the better reason for slowing down?
A - You have no right to go at that speed in an ice zone.
Q - And you think that all these liners are wrong in going at this speed in regions where ice has been reported?
A - Where it has been reported I think the possibility of accident is greatly enhanced by the speed the ship goes.
Not to scale but gives a good idea of the comparison between the Titanic, Carpathia, and Nimrod (Shackleton's ship)