Read the following passage given below and Answer the question.

Our second view of the Titanic was breathtaking. As we glided across the bottom, out of the darkness loomed the vertical knife-edge of the bow-the great ship towered above us and suddenly it seemed to be coming right at us, about to run our little submarine down. Gently we brought the sub closer until we could see the bow more clearly. It was buried more than 20 meters in bottom mud. Both anchors still hung in place.

Rivers of rust covered the side of the ship, some of it running the full length of the exposed vertical hull plating and pouring out over the bottom sediment where it formed great ponds as much as thirty to 12 metres across. The blood of the great ship lay in pools on the ocean floor. Then, as we rose in slow motion up the ghostly wall of the port bow, our running lights reflected off the still unbroken glass of the portholes in a way that made me think of eyes gleaming in the dark. In places, the rust about them formed eyelashes, sometimes tears: as though the Titanic were weeping over her fate. Near the upper railing - still largely intact - reddish-brown stalactites of rust, the result of rust-eating bacteria, hung down as much as several metres, looking like long icicles. I subsequently dubbed them 'rusticles', a name which seems to have stuck.

These rust features turned out to be very fragile. If touched by 'Alvin' (that was the name we called our sub), or dislodged by the thrust from one of our propellers, they disappeared in a cloud of smoke. And once the foamy crust had been knocked away, the steel beneath appeared almost perfectly preserved, only slightly pitted.

Carefully I counted the portholes aft from the anchor to locate the position where the ship's name should be, but I could see nothing.

Alvin rose farther, cleared the railing forward of No.1 hatch, and we manoeuvred in over the Titanic's mighty forward deck. All at once I was forcibly struck by the sheer size of everything: giant bollards, the huge links of the anchor chains, and even bigger shiny bronze-topped capstans. Until now the ship for me had been somehow ghostly, distant, incorporeal. Now it was very close, very real.

When did the opinion of the narrator about the ship change?

When he saw its immense size closely

The passage explicitly states that "all at once [he was] forcibly struck by the sheer size of everything." This sudden change in perception is clearly marked.