Regarding the Mexican ship accident
The accident over the weekend involving the Cuauhtémoc was tragic and had many elements that caused the crash. Here are my thoughts based on decades of recreational boating in New York’s waterways.
The current in the East River can exceed 5 knots (6-7 mph). For many vessels, this makes the "river" very difficult to navigate as the strong currents rush through an extremely narrow and winding channel about ten miles long between Hell Gate in the north to the Battery in the south. In olden times, there were many capsizes and deaths along the East River because the channel is so dangerous.
Likewise, the Hudson River has strong tidal currents that alternate four times a day, like the East River. Although not as fierce as the East River, the Hudson can flow upwards of 4 knots making it difficult to navigate against the current.
Motor vessels with sufficient power can sail against these currents but the powerful force of the water must still be taken into account by an experienced navigator. Sailing vessels, for the most part, must time their transits of these waters to maneuver with the tidal currents in order to maintain steerage, that is, the ability to control and handle the vessel.
I've traversed both rivers numerous times and I've almost always carefully planned the passages by consulting the tidal and current charts found in the annual publication Eldridge which shows the times of the tide changes as well as the expected currents throughout the tidal cycles. There are also several excellent electronic navigation devices that provide this information in real time. In spite of this planning, there are still difficulties, especially in the East River. For example, just north of the Queensboro Bridge at 59th Street, there are consistent standing waves of 2-4 feet during both the Flood Tide and the Ebb Tide that bounce boats around as they pass the area.
My sailboat has a Diesel inboard and it will power the boat with full throttle at just over 5 knots. I will never go against the East River current and on those occasions I've sailed against the Hudson's current it resulted in very slow passages. After all, if the current is 4 knots and I'm making 5 knots through the water, I'm only going 1 knot over the ground! This is almost the minimum speed to maintain steerage on my boat.
From the videos and accounts I've seen of the accident involving the Mexican vessel, the Cuauhtémoc, it appears that they undocked from Pier 17 and a tug boat was pushing the ship's bow to face south to head to the Atlantic Ocean. Apparently, the ship lost engine power (a 1,125 hp auxiliary engine) and the current (and wind) began pushing the ship north meaning that the ship was going backwards. This all happened so fast over such a short distance, less than a half-mile, that without functioning engine power, the ship didn't have a chance.
My only humble observation is that the ship might have timed its departure during the outgoing tide so it wouldn't be fighting the northwards current but would be pushed south towards the ocean. I wasn't there so I have no criticisms of the captain or the crew.
One commentator suggested that the tug could have saved the ship from the tragedy, This is a profoundly ignorant observation. Consider that the Cuauhtémoc is 300-feet long displacing 1,800 tons. A single tug, without control or tow lines connecting the two vessels, could never push the ship out of danger. It would take a coordinated effort by 2 or 3 tugs to properly escort the ship to safety.
This tragedy is very sad. Two sailors lost their lives. Many were injured, some severely. A beautiful sailing vessel was massively damaged with repairs probably in the millions. The ship's goodwill mission has ended. I'm curious where they will tow the ship for repairs as I'm unaware of a shipyard in the area that could handle it, (I'm sure there is a yard but I don't know where it might be).
This was a horrible accident and the investigations will provide more detailed information. It's a very sad event.
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I know a bunch of years ago before I retired, one of my direct reports and her hubby were "coasties" (as they called themselves) and were still in the reserves at the time. One of my trips to her office eventually netted me a weekend where I got chance to go on her and her hubby's 30 fter and their sea-doos, which were docked in an IN tributary to the OH River and we ended up traveling along the tributary out to the OH and sea-dooing there with the barges! 
I learned a lot about the "rules of the road (water) ", which was fascinating (like shifting to idle when passing under a bridge, etc).
One of my BILs was in the navy and one of my great-uncles (who I never met) was in the Merchant Marines (which is probably why I never met him since he was out to sea all the time 
). Another aunt's hubby's family had a houseboat docked in Lake Champlain that we visited years and years ago and one of my cousins actually lived on one down in the Baltimore area for a bunch of years.
I just say hats off to any mariners out there and there are a number who are DUers. It's a whole other world (and I expect, a great hobby to boot). 
Groton CT, hint.
Mind the bridge!
Those of us without extensive sailing experience appreciate it.
