The Beaufort Wind Force Scale is Weather Observation for Dummies

The purpose of the Beaufort Wind Force Scale is to enable observers at sea to estimate the true wind speed by making observations of the effects of the wind on the sea. As an aid pictures are provided so that the observer can match what is seen with the picture in the book that most closely matches what is being seen.

Evidently many mariners believe that the ability to use a picture book guide for wind velocity is the epitome of seamanship.

Here’s the captain of the El Yunque at the MBI.

Mr. Fawcett: I just want to ask you to restate something. You were asked a question about the ship’s anemometer and you made a comment. Can you take a moment to reflect on that comment and talk about the importance of the anemometer for shipboard operations?

WIT: The comment that I made was that I couldn’t think of anything less relevant than the anemometer to talk to Mike Davidson about.

CAPT Neubauer: Sir, can you just clarify if the anemometer is important to you as a Master on board the El Yunque.

WIT: No the anemometer is not important to me, it’s not a piece of required equipment. In fact, the assessment of weather and sea state and wind direction is done very well by looking out the window. You can also assess wind direction by looking at radar in terms of the direction that has the most sea clutter. And I would prefer ship’s officers to gain their information from there and then see if the anemometer is corresponding to that. That the reliance on a piece of digital data from a little wind propeller on top of the
weathervane on top of a mast that has air currents blowing all around it is not a gold standard on reliability of what’s happening with the wind. So I would prefer that to be used as a tool to verify. We do have an anemometer, it does work. I do not look to the anemometer to base a decision on what I’m going to do with the ship and the ship handling because that piece of equipment has a digital read out that says this. I do not think that the anemometer plays into my decisions on what’s going on with the vessel.

Don’t need a little wind propeller when you have a picture book guide.

Mr. Fawcett: In his final message from the ship, the El Faro to shore, Captain Davidson made the statement that he’s experiencing, not quote the word experience, but he reported heavy winds. What are the velocity of heavy winds?

WIT: Heavy winds is not a technical term. I can’t give a definition for what he described as heavy winds.

The term "heavy winds’ is too vague. Need a number.

MBI Mr. Fawcett takes the captain by the hand and leds him out to the bridge wing.

Mr. Fawcett: If you took me out on a bridge wing at night, how would I know the difference based on how you’re talking about observing the actual wind and radar clutter and so forth if the wind was blowing 70 knots or 105 knots?

WIT: I’ve not stood in 70 knot winds or 105 knot winds. I am not, I don’t have anything in my experience to tell you whether you’re standing in a 70 knot wind or 105 knot wind.I personally doubt that I would be standing in 105 knot wind.

Mr. Fawcett: Talking about the air currents around the mast where the anemometer is placed, using Bowditch, Knights Modern Seamanship or other tomes available to mariners, can you take the ship’s speed, the compared wind and convert it to true wind and true speed using the tools available on the bridge of a ship?

WIT: Yes.

Mr. Fawcett: And that would then give you an accurate wind speed?

WIT: Yes.

Estimating wind speed by observation is cadet level stuff, why is a captain taking pride in that skill?

These are the people that TOTE trusts 100% to avoid hurricanes, they think using a picture book to gauge wind velocity is the height of seamanship but need a computer to tell them the direction to the eye when it’s just a few miles away.


The testimony of this captain is surprising. With force 6 he does not need an anemometer, he uses his visual experience… and with force >10 he has no visual experience… this, navigating always in hurricane prone waters. Didn’t he know that the hearing was about the hurricane Joaquin?

The pictures to illustrate the Beaufort scale are normally from mid-latitude regions, on the lower side of deep and large depressions, where wind and seas often have the same direction for a certain time, at least away from the cold fronts. Other pictures would be meaningless for this purpose.

In front of hurricanes, this changes fundamentally. The waves advance in a straight way and the winds are nearly circular. As the waves propagate in all directions around the hurricane, there will be multi-cross waves.

Another problem is the vertical wind shear. On sailboats, the wind speed measured at the masthead (maybe 15/20 meters above) is higher than at the cockpit or sea level. The sails must be rigged in consequence.
The sea state (the visible whitecaps or breakers) is a function of the lower wind speed at sea level, and not of the real, stronger wind measured above. The waves were produced nearer to the center of the hurricane, by other winds. The winds may even blow perpendicular to the wave propagation.

Within these conditions, it seems very, very difficult to estimate visually the real wind speed and direction, and then estimate the distance and the direction to the center of the hurricane. During the night, I would say just impossible.

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Yes, the Beaufort Scale is for “fully developed seas”, low level stuff.

With regards to the Marine Board of Investigation, in some cases they were asking questions just to learn the answer, in other cases they were trying to determine the knowledge level of the witness. Seems like the captain thought he needed to teach the board something they didn’t know.


Mr. Keith Fawcett started his working career in the active duty Coast Guard serving on three Coast Guard Cutters and other various duty stations. He was an instructor at Small Boat Operations School as well as a guest instructor at the National Boating Safety School. Keith was a qualified boat coxswain in multiple vessel types. He served a little less than nine years before leaving the Coast Guard as a Chief Quartermaster.

After leaving the Coast Guard in 1979 Keith worked as a licensed deck officer for Gulf Fleet Marine Corporation and supported diverse oil field operations in Texas, Louisiana and Florida. Keith currently holds a 1600 Ton Near Coastal Mate’s License, 100 Ton Master, Radar Endorsement as well as Able Seaman Merchant Marine credentials. In 1981 Keith began working at the LOOP Marine Terminal as a Vessel Traffic Control Specialist. LOOP’s offshore unloading terminal is located twenty miles offshore of Grand Isle, Louisiana. LOOP is the nation’s premier facility for offloading ultra large crude carriers, the largest ships in the world carrying up to 4.5 million barrels of crude oil. In May of 2000, Keith returned to work with the Coast Guard as a civilian supervisor at the Vessel Traffic Service (VTS) in New Orleans. In this capacity he supervised a watch team that provided vessel traffic control service to the lower Mississippi River which included traffic control for the busy Algiers Point area in the heart of New Orleans. Keith also served as the Interim Director and Training Coordinator for the VTS and was selected to attend the International Association of Lighthouse Authorities (IALA) Symposium in Rostock, Germany to formulate training objectives for VTS operations worldwide. In September of 2010 Keith accepted a position at the Coast Guard’s Investigations National Center of Expertise in New Orleans. Keith has worked several high profile formal marine casualty investigations including the mobile offshore drilling unit KULLUK Grounding in Alaska and the DELTA MARINER bridge allision in the Land Between the Lakes in Kentucky. Mr. Fawcett is a subject matter specialist focused on providing expertise in human factors,fatigue, navigation, vessel operation and in assisting Investigators to interpret mariner interactions with the waterway. Keith assists the diverse segments of the marine community and USCG Marine Casualty Investigators in working together to reduce the occurrence of marine casualties.

Mr. Fawcett is one of the winners of the Sener Award for excellence in Marine Casualty Investigations.

I suspect he knows how to estimate wind speed at sea.

In the same MBI session the captain was asked if wind speed limits were used for voyage planning. The captain said wind speeds were never considered for planning purposes.

The issue is that wind speeds effect vessel maneuverability. A crude rule of thumb is that wind speeds above 3 times vessel speed will begin to impact the ablity to maneuver.

As sea height increases, that can force a reduction in vessel speed, the corresponding increase in wind speed will result in a decrease in available maneuvering options. This becomes a problem especially in areas where navigation options are limited.

Basically in heavy weather close to shore you might find your self backed into a box, while most mariners focus on wave height one of the sides of that box sometimes is wind velocity.

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Here’s a good graphic of the Beaufort Scale.

It’s easy to see that at as the wind speed increase the ranges increase. F-1 is a narrower range than F-11. This is because at low wind speeds it’s easier to detect slight differences in wind speed than a higher speeds. For example the visual difference between 2 kts and 5 kts can be easily seen compared to say 26 kts and 29 kts.

“Don’t need a little wind propeller when you have a picture book guide.”

I don’t see in the quote where he said anything about using a picture book guide. Are you just making things up to justify your position?

Looking out the window and estimating Beaufort force based on what you see, and probably using the pictures in Bowditch, is what KC meant when he paraphrased as “picture book guide”.

I think it’s a very fitting and succinct paraphrasing.

Sorry I don’t see it that way. I see it has him insulting the El Yunque captain in a condescending way.

I meant “as” not “has”.

It is a little condescending and if the El Yunque captain really believes what he said, as opposed to trying to cover for his comrade captain’s reputation, then I believe he deserves it.

I can’t read the captain’s mind as to what he really believes in the quote. It seems like he is answering the question as to the importance that he puts on the anemometer on his ship.

And if he really believes it’s just a stupid little “wind propeller” and it’s not to be trusted or relied on then I question his judgment.

I didn’t catch the part where he called it stupid. I did see where he called it “a tool to verify”. If one trusts or relies on an anemometer and doesn’t use other tools to verify, then I question their judgement.

He did everything in his power to downplay anemometers and make them sound unreliable and unimportant.

If his was unreliable such that it needed to be constantly verified by visual observations then it wasn’t working properly and needed to be reported to the office.

He called it a “little wind propeller”, that says everything right there.

It seemed to me that he was pointing out that anemometers don’t always get clean wind. They are subject to readings that can vary because of wind currents. He didn’t say that it constantly needed verification. It only takes a glance to verify the anemometer readings.

That is a pretty good description of it.

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If you’re sailing captain and you’re in the hot seat some slings and arrows are to be expected, goes with the territory.

If the captain of the El Yunque can’t take the heat he should stay out of the kitchen. Or at least if there is a stenographer present recording what you say at a public hearing, pick your words with care.

I thought the captain was being condescending towards the MBI, however he does seem to have changed his tone after that exchange.

The exchange about the anemometer was not about the anemometer, it was the captain saying that he thinks Fawcett is not qualified.

At one point the captain says this:

WIT: I can’t think of a less relevant thing to talk about, so no I never had a conversation about an anemometer.

But Fawcett, by asking about 70 and 105 kt winds works the captain to the point where he confirms that the anemometers is useful for wind velocities that are not commonly experienced.

Mr. Fawcett: And that would then give you an accurate wind speed?

18 WIT: Yes.

If the anemometer can be used to obtain accurate wind speeds what was that whole run around about?

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It sounds to me that part of it is the captain wanting to express the fact that he thinks officers should have a fuller understanding of marine meteo then just looking at the digital read out and writing down “winds 20kts@265 degrees” or whatever. When I first listened to this exchange I thought the whole thing was rather odd and tensed from both sides.