A new report to the U.S. Congress assessing a Chinese submarine-launched missile known as the YJ-18 highlights the danger, noting the missile accelerates to supersonic speed just before hitting its target, making it harder for a crew to defend their ship.
japantimes.co.jp/news/2015/11/01/asia-pacific/chinese-supersonic-ship-killer-makes-u-s-navys-job-harder/#.VtrwdPl95p9
japantimes.co.jp/news/2015/11/01/asia-pacific/chinese-supersonic-ship-killer-makes-u-s-navys-job-harder/#.VtrwdPl95p9