Free Republic
Browse · Search
General/Chat
Topics · Post Article

To: linMcHlp
A single screw boat / ship / vessel is prone to the propellor “walking” (known as paddlewheel effect or asymmetric blade thrust) - particularly when the vessel is set to run in Reverse motion.

So why was it so close to a support pillar in the first place? Other than that are you making the case this was all an accident caused by a sting of coincidences at exactly the wrong spot and exactly the wrong time?

60 posted on 03/27/2024 9:52:59 AM PDT by GOPJ (Democrats and MSM/NBC/MSNBC - the party of angry shrill bimbos.. weak men and sexual weirdos...)
[ Post Reply | Private Reply | To 4 | View Replies ]


To: GOPJ
A series of mechanical events plus weather condition that led to the ship changing course.

Wind, 8 knots from the east, gusts to 11 knots (I monitored FSK marine buoy FSKM2, for the windspeed and water temp: 42.8 deg F).

Wind on the port bow - a crosswind - at an attack angle of about 40 - 45 degrees to the ship centerline when the ship was in the lane approaching the FSK bridge. That wind naturally pushing the bow to starboard.

THE FSK BRIDGE LANE - See: Online Nautical Chart

You may download a nautical Baltimore area nautical chart.

A ship has to maintain speed and a rudder angle slightly to starboard, that keeps the bow somewhat into the wind, by keeping the stern a bit downwind. Similar to an airplane keeping its nose a bit into the wind, when on approach to landing, when in a crosswind.

When the power is lost, and the ship is adrift, the wind takes advantage.

This is happening when the ship is near ENOUGH the bridge - given ship's MOMENTUM.

The ship's crew tried an emergency reverse thrust.

THAT caused the stern to move to port.

So, bow to starboard, stern to port. Hence: New course to the bridge - toward the bridge support.

The Dali crew notified the FSK bridge authority of an emergency.

- - -

For perspective, try the same ship with a NE instead of E wind, and windspeed at 20 knots.

That would cause a very heavy load on the port side of the ship, and probably not wise to pass under the bridge.

Baltimore marine pilots probably have guidance about that condition - instructions, notices about "High Risk Periods."

- - -

OH NO! - Looking at International Maritime Pilots Association.

They have a manual: DIVERSITY AND INCLUSION (D&I) GUIDANCE FOR PILOTAGE - PDF file.

101 posted on 03/27/2024 11:27:09 AM PDT by linMcHlp
[ Post Reply | Private Reply | To 60 | View Replies ]

Free Republic
Browse · Search
General/Chat
Topics · Post Article


FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson