Setting flags - which way does the wind blow?

[rodgerdodger]

Setting Flags

 

My young granddaughter was looking at a model that I had recently completed.  She pointed to the flags and said in a very sweet voice “Grandpa – the flags are pointing in the wrong direction”.  It made me think as to why I had set the flags in the way I had and what was the correct solution.  I can’t find any comment on this matter in MSW so I thought I would get the discussion going.

 

The flags on my model were pointing to the bow of the ship and in her mind they should be pointing to the stern.  Her reasoning was that when she went riding on her scooter her hair was blown behind and not in front of her face.  So in her mind if a ship is heading forward in the open sea the wind would blow the flags backwards.  I tried to explain that even under full sail the wind is blowing faster than the speed of the ship moving through the water.   As the wind is blowing from the rear of the ship then the flags would be pointing forward.  From this I conclude that when model ships are fully rigged, with sails, the flags should be set pointing to the bow.  Especially so when the sails on the model are bellowed.

 

(Since this photo was taken I have worked on the flags so that they don’t look so new and drape a little more naturally.  However they still point to the bow.)

 

However when a ship is moored at anchor, with no sails set, the flags should be set pointing to the stern.  This is based on the fact that the ship will set with the bow pointing into the wind (assuming the wind is blowing).  So my conclusion is that any model ship that is not rigged with sails should have the flags set pointing to the stern of the ship.

 

When a ship is moored at a wharf then the flags could fly in any direction – wherever the wind might be coming from.  So you have to decide whether your ship model is moored at anchor or dockside and set the flags accordingly!

 

Flags do add a bit of colour and interest to models but I suspect that flags would not be hoisted when under full sale and not when moored even except in special situations.  I would appreciate any comment from someone with more nautical knowledge than I have on this.

 

PS  I am going to have to revisit a couple of models and reset the flags that don’t comply with the above, dammit.   Plus I hope my granddaughter doesn’t have any more clever questions!

Edited May 17, 2014 by rodgerdodger

[TBlack]

Rodger,

I think you got the wind direction right. What had me puzzled was this sentence:

 

 

 

 

Setting Flags

 

 

 

Flags do add a bit of colour and interest to models but I suspect that flags would not be hoisted when under full sale and not when moored even except in special situations. 

 

 

I always thought the flags were for identification and so would be displayed when underway?

 

Tom

[Modeler12]

Let me add one comment about wind directions. 

Ships don't always go before the wind. In fact, more often they don't. Usually the wind would be coming from port or starboard and the ship would be on a port or starboard tack. In that case the flags would be pointing in a direction that is off to the side.

The actual direction would be a bit more aft from the wind direction because of the ship moving forward (like your granddaughter pointed out).

Edited May 17, 2014 by Modeler12

[popeye2sea]

I always thought that the whole point of bracing the yards up sharp was to bring the windward edge of the sail closer to the wind.  So the apparent wind direction will usually be closer to the line that the yard makes across the ship, hence that is the direction that the flags should point.  

 

I also think that while underway some combination of flags are always flown, whether it be the national ensign, admiral or other commanders distinguishing mark, or signal flags.  Perhaps if the ship is underway, not in company with other ships then there might not be a flag displayed.

Edited May 17, 2014 by popeye2sea

[Modeler12]

[MEDDO]

I always thought that the whole point of bracing the yards up sharp was to bring the windward edge of the sail closer to the wind.  So the apparent wind direction will usually be closer to the line that the yard makes across the ship, hence that is the direction that the flags should point.  

 

I also think that while underway some combination of flags are always flown, whether it be the national ensign, admiral or other commanders distinguishing mark, or signal flags.  Perhaps if the ship is underway, not in company with other ships then there might not be a flag displayed.

 

 

This is how I always thought of it.  I saw this picture and the flag seems in line with the square yard.

 

[jwvolz]

If your model doesn't have sails, and thus no presumed wind direction,  point them any way you like and no one can tell you you are wrong. 

[Modeler12]

The picture that Michael shows (the Pride of Baltimore, I believe) shows some interesting points about the sails and directions.

 

I think we all know that the sails of sloops, including square rigs, rely on the same principle as airplane wings. That is, when the wind comes abeam, the driving force does not come from the wind 'pushing' the ship, but actually 'pulling' the ship forward. It is the differential pressure on the front and back of the sail that causes the forward force. This will give a sloop-rigged boat more speed than having a following wind to fill the mainsail.

 

The photograph clearly shows that the square sail spars are well ahead of the booms of the other sails. I don't know the actual direction of the wind, but my guess is that it is something like I show crudely below.

Why not have the booms pointing in the direction of the wind (like the spar on the square sail???). That is another question and involves the shape of wings, leading edges, etc. In fact, if you think of a sloop or schooner rigged sail as being only one half of a square sail, you can see that the sail might behave more like the square sail. 

Conversely, if one half of the square sail were used, the spar would end at the mast and become a 'boom'. Then it would not have to point as much. Hence the advantage of the sloop or schooner rig.

 

I still maintain that the flag is 'lagging' due to the forward motion of the ship.

Edited May 18, 2014 by Modeler12

[Jim Lad]

Another minor point regarding ships at anchor.  They may not be riding to the wind, but to the tide, or a combination of both, depending on the relative strengths of wind and tide, so flags on an anchored ship could still be blowing in any direction.

 

John

[rodgerdodger]

I realise from the responses that my introductory comments were too general.  I should have realised they apply to a square rigged ship sailing down wind with the yard arms square to the axis of the ship, as is the case with most ship models.  With other rigs there are far more solutions. 

 

The reason I brought it up is that there are some inconsistencies in models as illustrated in the following picture of La Couronne taken from the internet.

Edited May 18, 2014 by rodgerdodger

[Jim Lad]

OK, in the specific case you have, then the flags would be blowing towards the bow as you thought.

 

John

[wefalck]

Flags point in the direction of the 'apparent wind', see e.g. http://www.google.de/imgres?imgurl=http%3A%2F%2Fwww.sailingcourse.com%2Fkeelboat%2Fimages%2Ftrue-apparent-wind-2.gif&imgrefurl=http%3A%2F%2Fwww.sailingcourse.com%2Fkeelboat%2Ftrue_wind_calculator.htm&h=678&w=682&tbnid=fhlqbg3bXztHlM%3A&zoom=1&docid=tYl5Fc7fuXy6PM&ei=eRt7U9DhFqWK0AWk0oCwBg&tbm=isch&iact=rc&uact=3&dur=2026&page=1&start=0&ndsp=16&ved=0CFgQrQMwAA.

 

wefalck

[Guest EricD]

I usually don't put sails on my ship models and I weigh the flags down, pin them like they are at rest and then spray them with clear lacquer so they stay that way and it looks like there is no wind. 

[Stockholm tar]

Why not have the booms pointing in the direction of the wind (like the spar on the square sail???). That is another question and involves the shape of wings, leading edges, etc. In fact, if you think of a sloop or schooner rigged sail as being only one half of a square sail, you can see that the sail might behave more like the square sail. 

Conversely, if one half of the square sail were used, the spar would end at the mast and become a 'boom'. Then it would not have to point as much. Hence the advantage of the sloop or schooner rig.

 

You have to remember though that the Pride of Baltimore is a predominantly fore-and-aft rigged vessel, and carries only one small square topsail. If the fore-and-aft rigged fore and main sails were set on the same plain as the topsail, when going to windward, she would probably get no power from the wind at all or very little - which somehow defeats the object.

 

You mention the cutting away of one half of the square sail, and the spar becoming a 'boom'. In fact something very like this did happen - but not with a square sail, and not with a boom. During the Mediaval period, the loose-footed lateen sail became the norm on the mizzen mast of most European ships, which was adopted when their seamen came into contact with lateen-rigged arab craft in the Mediterranean, somewhere around the fourteen hundreds. They noted how efficient they were in going to windward, but were cumbersome in operation. Eventually, towards the end of the 18th century, the sail forward of the mast was removed, resulting in the gaff sail as we know it today. The lateen yard remained for a little longer (I believe the Victory for instance retained hers until around 1796), mainly I think because of its usefulness in replacing other damaged spars. However that too disappeared, resulting in the gaff, to which a boom was added.

 

Square rig actually has significant advantages over fore-and-aft, particularly in ocean sailing, where the winds are predominantly from aft, and which is why it has lasted for so long and is still the favoured rig. The Portuguese could quickly adapt the rig of their ships between the two when occasion demanded. Fore-and-aft rig is useful for coastal sailing where winds are usually more variable. Square rig is also safer on downwind passages, and it is on record that the crews of the large barquentines, with their enormous boomed out fore-and-aft sails, were petrified they would be dismasted if the wind got on the wrong side of the sail. This did happen on occasion. Come to think of it, I've often though that modern ocean racing yachts have the wrong sort of rig for the winds – they should be square rigged! I wonder if that's why they too are often dismasted.

 

However I side track...

Edited May 21, 2014 by Stockholm tar

[JerseyCity Frankie]

I love this photo for a lot of reasons. here it serves well to illustrate the flags position in relation to the square sails and the point of sail the ship is on. In this case the ship is being sailed as close to the wind as possible,  she is trying to point in the same direction the wind is blowing from. She can't sail directly into the eye of  the wind. But if she braces her yards around as far as they can go, so far that the sails are contacting the stays as is visible in the photo, she can get within six points of the eye of the wind. She is said to be "Close Hauled" and in this case she is close hauled on the starboard tack, since the wind is coming over the Starboard side. The flags as you can see are streaming aft and to port. 

The flags are ACTUALLY indicating a very very slightly different direction of the true wind since the speed of the ship through the water makes them behave a tiny bit differently than a stationary flag on a fixed point in the wind would behave. So if she was sailing past a rock with a flag on it, the flags on the ship and the flag on the rock would be at very slightly different angles. The one on the rock indicating the True Wind and the ones on the ship indicating the Apparent Wind.

[Modeler12]

Great picture, Frankie! I hope you don't mind if I repeat it here.

I know that sailing with the wind on the beam or close hauled can get you more speed than the speed of the wind itself. Hence, this will give you more speed than if the wind is aft. The recent America Cup races showed this very clearly. 

Edited May 26, 2014 by Modeler12

[HIPEXEC]

When I built my first ship...I took a vacation with my grandkids to a week on the beach. I got a chance to watch flags blowing in the wind. It changed the whole way I now look at flags flying. They do not wave neatly....they ripple and fold in crazy patterns. Nice job on your flags....and they do blow in the correct direction.

[Modeler12]

After seeing the picture above, I thought it might be interesting to go a bit further with sailing, wind direction, etc.

 

 

If we consider that there are 360 on the compass, there are some points that should be avoided when sailing with any kind of rig.

 

 

A sailboat does not do well going directly into the wind and typically has to veer off 30 to 40 degrees. In that case it is referred to as being 'close hauled'. Sloop rigged boats do a lot better with that than square sailed rigs. The diagram below is good:

 

 

 

 

There is also a good explanation on Wikipedia: 

 

http://en.wikipedia.org/wiki/Points_of_sail

 

 

 

Stockholm Tar also made a good point about ships sailing before the wind and the danger of the boom from swinging across when the wind shifts or the ship drifts off course a bit. Jibing is well known to skippers and helmsmen and should be 'planned' and not come as an 'accident'. To properly jibe, the boom, which is extended well outboard on the lee side, needs to be hauled in and gradually shifted as the ship makes a small adjustment in the course to let the wind fill the sails on the other side. Then the boom can be let out and the sails are fully filled. On small sailboats this can be readily done by hand, but on larger boats it takes some planning. Because of this we might include a small angle as another no-go zone. That is, stay away from winds coming from six o'clock.

 

 

 

 

But even at that, most modern sailing ships can handle winds coming from 270 to 290 degrees (out of 360 for the compass). Square riggers do worse because they cannot be close hauled as well. Then there is the issue of speed. And as you can read, a wind coming from eight to about ten o'clock (or 2 to 4 o'clock) will give ships the best forward force and speed and not from a following wind.

[Vonpapen]

Just look at a wind direction indicator on a sloop. The flag streaming position is a resultant of the wind speed and boat speed vector.

[Sonofagun]

You have to consider actual wind direction and the resulting apparent wind, ( the combined affects of actual wind speed and direction being affected by the speed and direction of the ship ) . In a square rigged vessel , most of the time the wind would be coming over one of the stern quarters. The ship's forward motion would move the flag's free end a little toward the stern from what the actual wind direction would have it go. The harder the wind is blowing, the less affect the forward motion of the ship would matter as the ship can only go as fast as its waterline dictates. (There is a formula for this but it would take too long for me to find it at this moment).

Basically, though, a heavy displacement ship gets stuck in its own 'trough' and cannot rise over the ridge in front. So, in a strong breeze. The flag would be snapping pretty much in the same direction of the actual wind. In a lighter breeze, the apparent wind would have a more powerful factor in

the direction of the flag. At anchor, the flags would be pretty much straight to stern as the ship, being tethered by the anchor rode, would be at the mercy of the wind