If that trend was the same for the 1/2 hour preceding when you were monitoring, the wind speed would have been around ~7 knots (or ~8 mph) with perhaps guests to 10 knots (or ~11.5 mph).
What was the distance the ship traveled when it lost power to impact? Would 8-12 mph winds be enough to cause that ship to change course that significantly in that span of distance?
:)
THE FSK BRIDGE LANE - See: Online Nautical Chart
You may download a Baltimore area nautical chart - PDF.
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The Dali, built by Hyundai Heavy Industries in South Korea, meeting the designs of the owner Oceanbulk Maritime SA and ocean transport service Maersk:
https://en.m.wikipedia.org/wiki/MV_Dali
was a "single screw” ship.
A single screw boat / ship / vessel is prone to the propellor “walking” (known as paddlewheel effect or asymmetric blade thrust) - partcularly when the vessel is set to run in Reverse motion.
From the rear view of a ship: A right hand prop rotates clockwise when the vessel is set to run in Forward motion . . . and counter-clockwise when the vessel is set to run in Reverse motion.
In Reverse, the stern of the vessel “walks” to port - to the left.
If the hull is "higher in the water," then the screw (the prop) is closer to the surface, and the "walk" efficiency increases.
The Dali, with wind on the port bow - a crosswind - at an attack angle of about 40 - 45 degrees relative to the ship (satellite/top view) centerline when the ship was in the lane approaching the FSK bridge. That wind naturally pushing the bow to starboard.
So, in the crosswind “working” on the very high and large “sail” (the vessel+containers) ship heading southeast, and now including the prop “walking” the stern to port . . . the FSK Bridge support was in the way.
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The ship has 1 stern rudder, plus 1 bow thruster.
When in forward motion (”under way”) with heavy momentum, but single screw in Reverse, the rudder is initially not a significant contributor, but you try anyway - and the helm had BOTH: the ship in Reverse and rudder HARD LEFT, at the last.
The bow thruster not much help - if it was working.
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Dali sister ship: MV Cezanne:
https://www.vesselfinder.com/vessels/details/9697416
https://www.marinetraffic.com/en/photos/of/ships/shipid:5481513/shipname:CEZANNE?order=date_uploaded
See: https://www.marinetraffic.com/getPhoto/?photo_id=4950293&photo_size=800
MV Cezanne appears to have a single rudder. Ship, when light and high in the water - the single prop is more effective at performing the “prop walk” to port, when ship is in Reverse.
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