This deserves a bit more because frankly, I'm getting tired of the nuts.

Indeed this might get added to my FAQ here (go see the section on "Troofers" for what happens if you run that garbage on my forum, whether in the comment section or otherwise) because it is getting about that stupid.

Let's talk a bit about boat handling, especially single-screw vessels.  Most props (unless you have twins) are what are called "right hand" screws.  When going ahead the torque effect and the rotation of the water column coming off the screw tend to move the stern of the ship to starboard, and since the vessel only has applied moment (force) at the stern this means if the stern goes starboard the bow goes to port.  Each vessel has an "effective" pivot center; exactly where it is varies, but it is not in the center of the vessel length-wise.  With an outboard it is often at or right near the transom, which can make close-quarter handling quite a mess in snotty conditions at low speed.  Gigabite, which was a Hatteras 45' Sportfish, pivoted at around her engine locations, which was roughly 10-15' or so from the transom (she had twin Detroit diesels.)

A twin engine vessel has one RH and one LH screw, and with both engaged she will track more or less straight because the two torque and rotation of the water columns cancel each other out.  But a single-screw vessel does not.  The other factor is that as way increases the water flow over the keel tends to keep her going in a straight line.

Further, the rudder gets most of its authority -- that is, the ability to steer -- from the blast of the prop which is directly in front of it, and at lower speeds through the water it has almost zero authority without the screw turning.  Note that the speed over ground does not account for current and the current is almost-never exactly aligned with your direction of travel, so it always, when it is present, attempts to destabilize the path of your vessel.  In harbors and similar tidal flow is the primary cause of said currents and of course they shift depending on whether you have a rising or falling tide and exactly where you are.  In some cases this can be quite-treacherous, especially if you get other than straight on with or against it; someone who was a dockmate of mine with a sailboat attempted to abort running Destin Pass with friends on board (that was stupid, by the way), got sideways and the boat was knocked down and dismasted.  That was a 40 footer too -- not a little rowboat.  Fortunately nobody was killed and the boat did not sink but two were ejected and had to swim to the jetties.

It is clear that the power went off on the vessel.  Why it went off remains to be determined but that it did, and that the emergency generator started when it did, is known because you can see the power go off and then come back on.  It then trips a second time, presumably due to an extreme demand (e.g. the skipper attempting a last-ditch use of the bow thruster at full power to keep off the piling.)  Note that the black smoke is not dispositive as to which engine was involved but that may have been the main being restarted and, if the main is direct-drive, and it frequently is on larger vessels, then you have to stop the prop entirely before you go astern because there's no transmission; the engine literally rotates the other way to go astern.

Until the power went down the ship was in the channel and on a stable heading.  It would have had some starboard rudder dialed in -- in other words, it was not set dead straight forward -- because the normal "walk" of the screw ahead would be to induce a port turn if it was dead straight.  When the power goes down that torque and rotational effect disappears and the rudder is now going to try to turn the ship slightly to starboard, and it is locked there with power off.  Add to this any current impact if the flow is in any way other than head-on (and as noted it almost never is straight on) and the impact of wind and that the ship began to yaw is not surprising, nor is it surprising it went to starboard.

Without power you now are riding on 100,000 tons of metal (and cargo) traveling at whatever velocity you were at underway which is subject to external forces you cannot counteract.  By the time the power comes back up it is likely there was nothing that could be done to prevent the collision but you can bet they tried -- the second power failure made those attempts irrelevant.  As you can see from the video when the power comes back again they're within seconds of impact.

Older machinery was not reliant on electrical power to work.  My boat had two mechanical diesels operated with cables from the bridge to the engines and transmissions; the transmissions (large ships are typically straight-shaft with no gearbox) were hydraulically operated by a pump driven from the engine.  Once started so long as they had fuel, air and lubricating oil they run.  The steering gear on my boat was hydraulic but with no booster so again, as long as the hoses and lines were intact and it had fluid in it you could steer but without the screws turning you had very little rudder authority.  I also had twin screws so at low speed I could steer without the rudder at all, and frequently did, since I could put one screw in forward and one in reverse, along with varying their speed.  I did have, during my time owning Gigabite, an electrical failure.  It was not a big deal as it occurred during daytime (at night you obviously have no running lights which is serious); we made port without incident and I fixed it.

Modern emissions requirements make no-electric-required operation impossible.  On a modern vessel without electrical power its engine shuts down because it is electronically controlled and the fuel pumps, conditioning equipment for the fuel, any after-treatment of the exhaust and various other required elements all require it, along with mechanical control being insufficiently precise to meet modern emissions standards.  While I could operate with no electrical power at all provided the engines were running before the failure occurred this is not true for modern vessels and engines.

Finally, contemplate that it would be close to impossible to actually know that causing a power loss of this sort, assuming you could, would result in this sort of calamitous outcome.  Exactly where that ship goes when the power goes off is determined by facts you cannot know with sufficient precision in advance; if the tide or wind had been different it might have gone right under the span and, if it had, there would have been no calamity at all (however, it might have gone aground on the other side somewhere once it got out of the channel.)

This does not mean that there should not be liability.  Admiralty Law is very different than what you think of as "legal liability code" in this regard and it is both older than the US and time-tested.  A ship can literally be arrested under Admiralty Law, for openers and in addition the owners of the cargo on board can be assessed as well in a major casualty incident such as this.  Obviously the physical damage is in the billions, never mind the (small, but real) loss of life, all of which is chargeable on a liability basis.  That will take time to sort out but it absolutely does exist and can be sorted out -- for an example see Ever Given in the Suez which was impounded by Egypt when the owners and insurers refused the original demand to pay a billion in economic damages.  The harm here is obviously much-greater although it certainly includes the disruption of port business which was the primary harm (disruption of transit) from the Suez incident.

Finally, as with the Suez incident there were local harbor pilots on board and in command, as is the case for vessels of this sort and size (yes, including cruise ships) coming into and leaving ports -- although in virtually all cases the vessel's master is still ultimately responsible (and will get tagged if something goes wrong.)  That's done because those local individuals have very extensive experience with that specific passage where a ship's captain does not -- he or she may have only been through there once or twice where these officers run this particular passage, in many cases, every day or every few days.

Large commercial ships also have data recorders similar to an airliner's "black boxes" and I'm sure by now the USCG and other US authorities have them in-hand and will be going through them.  They include both very detailed machinery logging as well as voice records.  From that the precise sequence of events, including the orders given (and by whom) will be able to be determined.

But from what is known now -- and in fact what was known at the time the event occurred I see nothing to suggest that this is anything other than an extremely serious industrial accident.  Are there lessons to be learned and mitigations that can be taken on a forward basis?  Of course -- but whether they'd have been successful if put in place in advance (e.g. "dolphins" around the pylon) in preventing the collapse are, at this point, speculative.  Frankly, with 100,000 tons of ship moving at 8kts even if said bollards had been present it is not at all clear thy would have actually prevented the contact and destruction of the bridge.