As has been reported in the press, the findings of this latest hearing have revealed that the vessel was receiving weather information that was 10 hours out of date around the time that Joaquin intensified. This means that the crew did not have an accurate track of the storm and may explain why evidence from the ship tracking data indicated that the El Faro was at near full speed going into the centre of the storm before it lost propulsion.
Professional mariners can’t be expected to have an in-depth understanding of the complexities of the tropical cyclones, the accuracy and possible errors in the forecasts and so forth, so it’s important what tools are used for avoidance.
The linked article briefly discusses the situation with the El Faro
The time is more than 12 hrs before departure Jacksonville. The small red oval is presumably the 34 kts wind field at 5 am tues the 29th.[/QUOTE]
I believe the small red oval is the (position) error factor at the initial time, based on the figure note from the article. Error factors for initial, 24, 48, 72 hours–four red circles/ovals.
The 34-knot wind radius rule
states that ships should stay
outside the area of a hurricane
where winds of 34 knots or greater
are analyzed or predicted. Often
this area is not symmetrical
around a hurricane, varying within
semi-circles or quadrants.
Here is the 29/0500 LT
TROPICAL STORM CENTER LOCATED NEAR 26.6N 70.6W AT 29/0900Z
POSITION ACCURATE WITHIN 30 NM
PRESENT MOVEMENT TOWARD THE WEST OR 270 DEGREES AT 4 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 1002 MB
MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT.
34 KT… 0NE 60SE 0SW 0NW.
12 FT SEAS… 0NE 90SE 0SW 0NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.
Here is 24 hr forecast
FORECAST VALID 30/0600Z 26.7N 72.2W
MAX WIND 40 KT…GUSTS 50 KT.
34 KT… 30NE 60SE 30SW 30NW.
The initial +24 hr circle should be 60 miles + 100 miles for forecast error.
TROPICAL STORM CENTER LOCATED NEAR 25.4N 72.5W AT 30/0900Z
POSITION ACCURATE WITHIN 25 NM
PRESENT MOVEMENT TOWARD THE WEST-SOUTHWEST OR 245 DEGREES AT 5 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 988 MB
MAX SUSTAINED WINDS 60 KT WITH GUSTS TO 75 KT.
50 KT… 40NE 50SE 0SW 0NW.
34 KT…100NE 110SE 40SW 60NW.
12 FT SEAS…150NE 90SE 60SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.
Here is the diagram for the 30th/0500 LT again. This would have been the morning after departure (departure was 29/8:10 pm LT), about 24 hrs before the ship went DIW.
The red dot marked 5AM WED is the Current Storm Position for 34kt/1-2-3 plotting, that would have been 30/0900z
TROPICAL STORM CENTER LOCATED NEAR 25.4N 72.5W AT 30/0900Z
POSITION ACCURATE WITHIN 25 NM
PRESENT MOVEMENT TOWARD THE WEST-SOUTHWEST OR 245 DEGREES AT 5 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 988 MB
MAX SUSTAINED WINDS 60 KT WITH GUSTS TO… 75 KT.
50 KT… 40NE 50SE 0SW 0NW.
34 KT…100NE 110SE 40SW 60NW.
12 FT SEAS…150NE 90SE 60SW 120NW.
The “1” in the 1-2-3 for the plot would be the 24 hour forecast it is the 2AM THU on the plot from the same advisory #10, this is of interest because it is for the approximate time of the encounter.
FORECAST VALID 01/0600Z 24.7N 73.8W
MAX WIND 75 KT…GUSTS 90 KT.
64 KT… 30NE 30SE 0SW 20NW.
50 KT… 50NE 50SE 30SW 30NW.
34 KT…110NE 110SE 60SW 70NW.
This is the forecast that is plotted as the red ring around the 2AM dot which would be a radius of 210 miles (110 miles for 34 kt radius and 100 mile for forecast error).
This is the actual conditions for the time the ship went DIW 01/0500 LT:
HURRICANE CENTER LOCATED NEAR 23.4N 73.7W AT 01/0900Z
POSITION ACCURATE WITHIN 25 NM
PRESENT MOVEMENT TOWARD THE WEST-SOUTHWEST OR 240 DEGREES AT 4 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 948 MB
MAX SUSTAINED WINDS 105 KT WITH GUSTS TO 130 KT.
64 KT… 25NE 30SE 20SW 20NW.
50 KT… 40NE 60SE 30SW 40NW.
34 KT…100NE 120SE 100SW 80NW.
12 FT SEAS…220NE 180SE 100SW 180NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.
Max winds forecast 75 kts, compared to 105 kts actual, the position is in error by about 80 miles. The forecast radius of the 34 kt winds had a max error of 10 miles.
There has been several places where the El Faro and the 1-2-3 avoidance rule has been discussed. Most mariners agree that the El Faro did not have an adequate margin, however the fact that the El Faro’s planned route was inside the so-called “Area to be Avoided” that fact alone does not necessarly mean that it was in violation of normal practice.
The 1-2-3 rule’s "area to be avoided’ in some cases can be a very large area. For example; a tropical cyclone moving at 15 kts, the area to be avoided will extend 1380 miles and almost 4 days ahead of the inital position. In fact there will be very few if any vessels that will avoid an area that far ahead of a TC if the geography is such (for example destination port is cut off) that avoiding that area requires waiting for the TC to pass.
The exact wording of original article is:
Therefore, when a hurricane’s track is plotted, a 100-mile error for each 24-hour period must be applied and a vessel within this adjusted area must take action as if a hurricane were bearing directly toward them, which may become the case.
A track inside the 1-2-3 “area to be avoided” requires an understanding that in the future the vessel may find itself directly in the path of the hurricane,
Instead of looking only if the track entered the “area to be avoided” to determine if a track is “in violation” the other part of the avoidance rule, the 34kt radius rule needs to be considered as well.
The 1-2-3 rule is a tool or an aid to ensure that the vessel does not enter or is at low risk of entering the 34 kt wind field of a hurricane. The 1-2-3 rule takes into account both the area of the 34 kt wind field and the uncertainty or error in the forecast.
What specific means are used is much less important then the goal of actually staying outside the 34 kt wind field. The 34 kt Wind Radius Rule should be considered non-negotiable,
Here is the 34 Wind Radius Rule
Thirty-Four-Knot Wind Radius Rule
The 34-knot wind radius rule
states that ships should stay
outside the area of a hurricane
where winds of 34 knots or greater
are analyzed or predicted. Often
this area is not symmetrical
The 1-2-3 Rule is a very useful framework to understand how to avoid the 34 kt wind field of a hurricane. But apparently neither the El Faro nor the El Yuque intended to do that. If those ships had no intention of avoiding the 34 kt wind field than what tools or process was used or not used is beside the point.
