USS Connecticut (SSN-22) is a Seawolf-class nuclear powered fast attack submarine.
Bearing in mind that these subs have ample state of the art detection equipment like sonars, pingers and what not, it is curious that this could happen. Blind for a large object, large enough to damage the sub and to injure a number of sailors in the process. All sirens and bells should have sounded! Worrisome to say the least.