Estimating Wind Speed/Direction

Professional Mariner Forum
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This continues a discussion on the El Faro thread concerning the utility of anemometers.

When I went to maritime academy we were taught how to determine true wind direction and speed using an anemometer, a maneuvering board and vector diagrams (remember those?). Well and good. Then I graduated and began working in the Bering Sea. We had anemometers. Sometimes they were to be trusted. Sometimes not. Sometimes they “worked“, but the reading was patently false. Venturi effects and wind channeling peculiar to the wheelhouse structure affected the anemometer on certain courses at a certain wind speeds.

Few skippers really cared, because most of them determined true wind by looking out the window and at the gyrocompass. The angle of the waves to ship’s heading told you wind direction. The faculty of judging of wind speed was developed by a curious osmosis of studying the sea state when the anemometer deigned to work, listening to the weather reports of nearby vessels, and, most importantly, by referring to the Beaufort Scale. Admiral Beaufort knew his stuff, and the laws of physics have not been repealed or altered since he came up with his scale in 1805. In the GoA and Bering Sea in Winter, in a 200’ boat, you got good at judging wind direction really quick.
One could say that reading an anemometer requires no experience. That would be correct, but doesn’t acknowledge the fact that anemometers can blithely lie. And how many times did a mate do vector diagram, get it wrong, and blithely log the results?

What did we do at night? Simple. We turned on the decklights and looked at the sea. The horror! Weren’t all those cones and rods in our eyeballs fried? They were already offended by all the radars and indicator lights in the wheelhouse, so no harm was really done.

When the atmosphere was white with flying spray and the wind was past 100 knots (which was not as rare as we would have preferred) our cheap anemometers died of fright anyway. (Thanks “Kraken” for the tip on Ultrasonic 2-axis anemometers. We will look into those…).

I do some training with some state school maritime academy students nowadays. They are bright, well-motivated, and learn quickly. Nevertheless, one or two years into the academy, some are unable to tell which way the true wind is coming from just by studying the sea, mostly in light winds. Similarly unaware of the importance of tidal currents in navigation. But then they are here to learn, and they have to start somewhere. I just hope the academy makes a big deal about these basic facets of a deck officer’s life, later on in their training. Sometimes we lose the forest for the trees.

Someone with a mate’s license has no excuse not knowing how to estimate the wind with nothing but a compass. Years ago I was captain of a freighter in the middle of the Gulf of Alaska. Our true course was about 270 degrees. A 15-knot wind was coming dead out of the West. At about 0100 hours with an overcast sky, the gyrocompass tumbled due to a momentary loss of a genset. Standard procedure: steer by magnetic compass until the gyro settled down. Trouble was, it was a new boat, and being an uninspected vessel, the position of the binnacle was not as rigidly prescribed as it would be otherwise. In short, it was not placed near enough to the steering station to be useful. Stupid, I know. It was changed after the voyage. But there we were, in pre-GPS days. The mate on watch called me immediately and asked me what to do.

The situation was ridiculous in regards to binnacle placement, but not a total loss. The wind was from the West and were headed west at 11 knots. It was easy, I said. The helmsman should keep the bow at right angles to the waves, while the mate kept an eye on the magnetic compass, until the gyro settled. No targets on the radar screen, on a normally empty bit of ocean.
Neither the mate or the helmsman could do it! They had absolutely no idea of how to tell the direction of the waves, and therefore how to steer into them! First one and then the other took the wheel and yawed about, while the other called out headings and corrections. Long story short, I had to stay up there for the 90 minutes and steer myself.

After that I took it on myself to make sure mates and helmsman could do what should have been second nature to an experienced mariner. Nowadays we have in-company training. We have a training boat. If you jump from OS to AB, or AB to mate, you put in your time on the training boat to learn piloting, a part of which is judging the wind. I find the same thing. Lots of “experienced” seaman are clueless about sizing up the wind visually.
Dear Ann Landers: Am I hopelessly out of date? Signed: Blow Hard in Seattle.

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good post. People who didn’t grow up around the water (fishing/sailing/surfing) have a hard time with this. The filipinos onboard my ship typically don’t grow up doing these things, so it takes a while to break in a cadet for example. Every single day I ask the cadet what the wind force and direction is via the Mark I eyeball. It usually takes a full month or more before they can get it to +/- 10 degrees, which is more than enough. After that, it is on to guessing the swell direction (if groundswell), then determining the approximate current using HDG and STW vs COG and SOG, which some people never get. These are important basic skills to have in our industry.

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[QUOTE=edchuckBB;186218]good post. People who didn’t grow up around the water (fishing/sailing/surfing) have a hard time with this. These are important basic skills to have in our industry.[/QUOTE]

Absolutely. As a sailing instructor in my wild youth, if a student couldn’t tell wind direction after several sessions on the water, I would try to steer them toward some other activity. The CG with the Eagle and the Naval Academy in Annapolis with their fleet of sailboats stress the importance of sailing for good reason. It’s a basic skill that should be part of training in Merchant Marine Academies. I was very surprised when I started sailing on commercial ships that so many on board were clueless about something that should have been second nature.

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There are three basic ways that the mates determine wind speed and direction on ships equipped with an anemometer.

The new mate way,read the direction and speed off the instruments and then they enter the data into a computer program (Waypoint for Windows for example) that converts relative to true and they log that.

The experienced but lazy way is to just walk over to the compass and get speed and direction by observing the effects of the wind on the sea. Mates (or captains) don’t do it that way just because they have experience but because it quick, easy and accuracy usually doesn’t matter that much.

The third way, the experenced and careful way is to both read the anemomter and to verify visually.

What about at night? If the anemomter has proven accurate most mates in a routine situaton will just take the reading without much checking.

What about the case of at night no working anemometer? In my experenced they look to see what the last guy wrote down and write in the same thing or change it up a little if they think conditions have changed.

In the case of the El Faro this is where what was expected would have been important. If the last watch wrote down, say (for example) WxN F-7, next watch might think wind noise has increased so call it WxN F-8.

This is why an anemometer might have helped. For example it may have made the weather observation taken and logged by the mate more trustworthy and therefore most useful. The one hint that things were not right may have been that as they approached the center the wind direction would have been changing clockwise rather than the expected counter-clockwise. If you looked at what the last watch logged and it didn’t match what was expected the mate might figure the previous watch just made an error.

Better information would increase the probabilty that the true situation would have become known. I don’t see how that is in dispute. Of course if the crew thought that gettng the direction correct was important than likely they could have done it. But if they were confident they understood the situation there is no reason to they would have been concerned about it. People tend see what they expect to see.

It would be a tough argument to make in a courtroom, that the instrument used to measure wind speed and direction is of no help in that task and that the average mate will do just as well without one.

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It occurred to me that the title of this thread, Estimating Wind Speed Direction" is not really the point.

What does the mate do when underway at night in bad weather and a gust of wind hits? They don’t jump up and turn the lights on to have a look, they look at the anemometer, not to compute speed/directon but just to get a reading. For example the mate could tell the captain or his relief, “it’s been reading under 40 kts but just the last half hour it’s starting to jump over 45 or 50.” That alone is good, uesful, objective information and even without being converted to true it can be easily understood and communicated.

True speed and direction is often not really needed to help understand and communicate the situation. Is it backing or veering? Increasing or moderating? Just observing the behavior of the gauges can often be very useful.

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[QUOTE=Kennebec Captain;186304]It occurred to me that the title of this thread, Estimating Wind Speed Direction" is not really the point.

What does the mate do when underway at night in bad weather and a gust of wind hits? They don’t jump up and turn the lights on to have a look, they look at the anemometer, not to compute speed/directon but just to get a reading. For example the mate could tell the captain or his relief, “it’s been reading under 40 kts but just the last half hour it’s starting to jump over 45 or 50.” That alone is good, uesful, objective information and even without being converted to true it can be easily understood and communicated.

True speed and direction is often not really needed to help understand and communicate the situation. Is it backing or veering? Increasing or moderating? Just observing the behavior of the gauges can often be very useful.[/QUOTE]

Both posts were excellent KC. I’d prefer that all the mates be proficient in monitoring and determining the winds as well as the seas by whatever means necessary. That is not always the case unfortunately. When I wake up from the ride deteriorating and shuffle my half asleep ass to the bridge, the details of what the trend has been are always useful.

Explaining to a new third mate the importance of whether the wind is backing or veering, or whether the seas are clocking around towards the bow causing the ship to start digging in is a sometimes daunting task. When you find one that really gets it, you sleep a lot better at night.

For my particular ship, we use a completely digital anemometer which is mounted on the port yard arm of the aft masthead. When the wind is from broad on the port bow to about two points abaft the beam, you will see grossly aberrant and inaccurate readings. I can track these in the log book and question the mates whether a discernible increase in wind noise or sea state was present for them to log such a drastic change in the wind direction and strength. This is usually after I’ve warned them of the limitations of the equipment.

I still rely on my eyes to read the seas and wind during the day and my ass to read (the seas at least) at night. If I need further clarification I turn on the deck lights. The most important skill I want all my mates to have is to question everything. Every piece of bridge equipment must be taken at face value. Check, cross check, and then triple check to be sure. Then go make a cup of coffee.

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[QUOTE=DamnYankee;186325]Both posts were excellent KC. I’d prefer that all the mates be proficient in monitoring and determining the winds as well as the seas by whatever means necessary. That is not always the case unfortunately. When I wake up from the ride deteriorating and shuffle my half asleep ass to the bridge, the details of what the trend has been are always useful.

Explaining to a new third mate the importance of whether the wind is backing or veering, or whether the seas are clocking around towards the bow causing the ship to start digging in is a sometimes daunting task. When you find one that really gets it, you sleep a lot better at night.

For my particular ship, we use a completely digital anemometer which is mounted on the port yard arm of the aft masthead. When the wind is from broad on the port bow to about two points abaft the beam, you will see grossly aberrant and inaccurate readings. I can track these in the log book and question the mates whether a discernible increase in wind noise or sea state was present for them to log such a drastic change in the wind direction and strength. This is usually after I’ve warned them of the limitations of the equipment.

I still rely on my eyes to read the seas and wind during the day and my ass to read (the seas at least) at night. If I need further clarification I turn on the deck lights. The most important skill I want all my mates to have is to question everything. Every piece of bridge equipment must be taken at face value. Check, cross check, and then triple check to be sure. Then go make a cup of coffee.[/QUOTE]

Excellent post.

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[QUOTE=DamnYankee;186325]For my particular ship, we use a completely digital anemometer which is mounted on the port yard arm of the aft masthead. When the wind is from broad on the port bow to about two points abaft the beam, you will see grossly aberrant and inaccurate readings. I can track these in the log book and question the mates whether a discernible increase in wind noise or sea state was present for them to log such a drastic change in the wind direction and strength. This is usually after I’ve warned them of the limitations of the equipment.

I still rely on my eyes to read the seas and wind during the day and my ass to read (the seas at least) at night. If I need further clarification I turn on the deck lights. The most important skill I want all my mates to have is to question everything. Every piece of bridge equipment must be taken at face value. Check, cross check, and then triple check to be sure. Then go make a cup of coffee.[/QUOTE]

We changed our “squall” power management because a DPO on another rig didn’t have the right wind sensor selected. The sensors are located on various points on the rig and provide immediate feedback to the DP system. If the wrong sensor is selected you will get inaccurate readings. Their rig got blown off position by a pretty good gust of wind. The selected sensor didn’t even capture the peak windspead.

The company decided that all available engines connected was a better way to deal with squalls than making sure the DPOs could see which way the wind was blowing.

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[QUOTE=Kennebec Captain;186304]
True speed and direction is often not really needed to help understand and communicate the situation. Is it backing or veering? Increasing or moderating? Just observing the behavior of the gauges can often be very useful.[/QUOTE]

[QUOTE=DamnYankee;186325]
Explaining to a new third mate the importance of whether the wind is backing or veering, or whether the seas are clocking around towards the bow causing the ship to start digging in is a sometimes daunting task. When you find one that really gets it, you sleep a lot better at night.[/QUOTE]

No arguments here. A case of certain mariners relying 60% on instruments and 40% on eye, and others doing the reverse. Either works just as well.

I must say, however, I’m a champion of turning the deck lights on for a moment or two to study the sea-state: size of waves and swells, wind direction/ speed, amount of spray. I’m talking about on the open sea, with usually no traffic on the radar, so the deck lights don’t obscure the running lights. And yes, I check which way the wind direction is moving, too. That’s all important, if you’re hove-to in 20’-30’ foot seas, wondering whether to stick things out, or to turn tail and run.

In bad weather I believe in turning the deck lights on a few moments every hour. Even more often, in some cases (see the discussion of deck cargo, below). I suspect there are some captains out there who are against turning on deck lights at night for anything except an emergency. If there are, I’d like to hear their side of things.

My trade is Aleutian freighters. Part of the insistence on visually checking sea-state is a by-product of the deck cargo an Aleutian freighter carries. In heavy weather, turning on the deck lights once an hour during the watch so the OOW can visually check the deck cargo is the rule, not the exception. Why? In case the deck cargo shifts, or in case lashings come loose. At which point the captain is awakened, and makes the call as to dealing with the problem then, or waiting until daylight. Coincidentally, that’s when properly logged wind observations are vital. Recent changes in wind direction/velocity may affect the captain’s decision whether to hove-to at that moment, or to spin the ship about to put the weather on the stern and slow down, in order to safely send the deck crew out on deck to lash things down. It all starts with turning on the deck lights to see what is happening. A stitch in time saves nine.

Moving away from wind observation to weather observation in general, particularly at night: In the GoA, December to March, icing is always a hazard. As in “building-up-enough-ice-to-capsize the-ship” hazard. As the thermometer drops, the captain tells the mate to watch out for ice build-up, the rate of which can be deceptive for the uninitiated. The only way you’re going to check that at night is by turning on the deck lights. You’re visually gauging the ice build-up, of course, but you’re also looking for the flying spray, which leads to the icing.

That’s when you explain to the mate that the wind speed/direction isn’t just a number going in to a log. It’s the difference between a normal voyage, or suddenly wasting hours or days because you are forced to head due South to forestall capsizing due to icing, or at the least, days of backbreaking work chipping through 6 inches of ice on deck just to open a cargo hatch. And you don’t need to be in heavy seas to ice-up. Simply bucking through 12’ seas can raise enough spray to seriously ice up a small ship, as you experienced captains know.

So you tell the mate to turn the deck lights on a few moments every hour at night and observe. Flying spray, with the air temperature 20 degree? You are icing. No doubt. A change to a weather-course might reduce the problem, but you have to realize you have the problem to begin with. Which goes back to my original post, a major tenent of which, I think, we are all agreed with: you want to get your mates trained as to real-world importance of wind as soon as possible.

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[QUOTE=freighterman;186400]

So you tell the mate to turn the deck lights on a few moments every hour at night and observe. Flying spray, with the air temperature 20 degree? You are icing. No doubt. A change to a weather-course might reduce the problem, but you have to realize you have the problem to begin with. Which goes back to my original post, a major tenent of which, I think, we are all agreed with: you want to get your mates trained as to real-world importance of wind as soon as possible.[/QUOTE]

If the deck lights didn’t work and a ship iced up and had trouble you might come on here and say the lack of deck lights might have contributed to the trouble. Everyone would say If the mate was worried about icing he should be able to tell if it is occurring or not without having to be told to turn the lights on every hour. Any mariner worth his salt should know enought about icing and back in the day yada yada yada… This could keep up for many post, others trying drive home the seemingly obvious point that there are alternatives to turning the deck lights on once an hour.

LIkewise if the mate was concerned about the wind direction and thought it was important he could determine it without a anemometer. What they really needed however was to be concerned about was the position of the center. There are other way of derterming that as well, the most obvious being NWS forecasts. Those forecasts should have been required to be plotted.

One thing that might have helped, without a good forecast, is a procedure to record accurate weather observation data hourly regardless of what the concern was. This is standard practice and to say that wind speed and direction can be determined without an anemometer is missing the point.