Complex sentence: Its range was 9,900 yards (9,000m) at 49-50 knots, or 13,200 yards (12,000m) at 45 knots; which is about three times the range of the American Mark 14 with the same speed.
Split into simpler sentences: Its range was 9,900 yards (9,000m) at 49-50 knots, or 13,200 yards (12,000m) at 45 knots. That's about three times the range of the American Mark 14 at the same speed.