At high TC it can be anything like mines, land, another vessel (there is a lightship in the area), sometimes at such high TC you really don't see it, and your crew are very delayed even if the watch officer is on the bridge! You start taking damage and by the time you know about it it's too late.
I'm sure we've all done it, and we'll probably all do it again - it'd be nice to go slow sometimes but pressures of RL just take over (nagging wife usually...!)
Welcome aboard
and sail safely.