Original: Passengers on the Explorer reported a loud "bang" at that time of impact, although others reported that there had been no noticeable impact, or at least nothing more than the normal crunching of ice experienced when sailing through icy waters.
Simplified: Although some reports indicate there had been no noticeable impact, or at least nothing more than the normal crunching of ice experienced when sailing through icy waters, other reports say that there was a loud bang.