USCG Exam Question: Apparent Wind

[OldFrog75]

Originally Posted by monte

Nautical. a point of sailing in which the wind is within a few points of the beam.

It's all good. Semantics I guess. I would not consider 15 degrees to be within a few points of the beam.

[med]

Originally Posted by OldFrog75

It's all good. Semantics I guess. I would not consider 15 degrees to be within a few points of the beam.

One point is 12.5 degrees. 15 degrees is well within a "few" points. (The traditional compass is divided into 32 points).

[Wotname]

Originally Posted by med

One point is 12.5 degrees. 15 degrees is well within a "few" points. (The traditional compass is divided into 32 points).

Try 11.25 degrees

[OldFrog75]

Originally Posted by med

One point is 12.5 degrees. 15 degrees is well within a "few" points. (The traditional compass is divided into 32 points).

Got me on that one. Should've just stuck with my statement that I think beam reach is much closer than 15 degrees off perpendicular to the wind....

[med]

Originally Posted by Wotname

Try 11.25 degrees

Oops. Not too hot on the mental arithmetic today.

[jheldatksuedu]

After trying to take a nap, unsuccessfully I might add, due to thinking about this problem, I thought about an ice boat, and figured out that a sailboat that is sailing on a beam reach with the apparent wind at a right angle to the boat would actually be sailing downwind and the more efficient that a boat is, the more downwind it will be heading.

Thus to me it would now seem ridiculous to define a beam reach as 90 degrees to the apparent wind, it must be true wind. An ice boat might be able to sail on a beam reach at a speed that is close to the wind speed so it might be heading 45 degrees or more down wind. See vector diagram. So beam reach must be to true wind, which would make it extremely difficult to be precise since it is very difficult to know the true wind while sailing and the wind would be somewhat forward of the beam. I would expect that most sailors would sail with the apparent wind at 90 and call it a beam reach. I would have before this.

Now an interesting story about an ice boat, or an attempt at an ice boat. Tuttle Creek, the reservoir that I live on in Kansas and where I learned to sail, froze one year hard enough to walk on with no snow, smooth like glass, with an occasional expansion pressure crack. I've never skated on such a large surface, a couple miles wide by 40 miles long. I spent the evenings that week building a sort of ice boat, imagine a 2x4 triangular frame with a cut up bicycle fork bolted up front with a 2x4 in place of the wheel, and a push pull stick for a rudder. Two 2x4 runners at the back of the triangle, then sharpened steel T iron screwed on the bottom of each of the runners and an attached lateen mast, boom and sail rig from a 13 foot sailboat. I took this out on Saturday and I discovered a major mistake in my engineering, and knew it immediately, it would not move on inch. I had sharpened the runners to knife edges, and I knew full well that ice skates are hollow ground on the bottom to trap a layer of liquid water melted by the extreme pressure. So I put on my ice skates grabbed the 2 booms of the latteen sail off I went, traveling at extreme speeds, probably 35 or 40 mph in the 15 knot winds. To tack I just flip the sail over from one side of my body to the other, I was great fun, until I had the nose of the sail to far up and immediately became a hang glider, probably 5 feet off the ice. Crashing down to the ice in a surprised mass of body and sail. I decided that was too dangerous for me, the ice wasn't that thick. The next night it snowed, ruining the ice and the lake has never frozen like that again and I have never been able to attempt ice boating since.

[jheldatksuedu]

Originally Posted by jheldatksuedu

Thus to me it would now seem ridiculous to define a beam reach as 90 degrees to the apparent wind, it must be true wind. An ice boat might be able to sail on a beam reach at a speed that is close to the wind speed so it might be heading 45 degrees or more down wind. See vector diagram.

I didn't get the diagram uploaded

[jheldatksuedu]

try again

[navy davy]

Remember the answer to this question, it could save your life some day.

[JPA Cate]

Originally Posted by navy davy

Remember the answer to this question, it could save your life some day.

OK, I'll bite: HOW will "none of the above" save my life? An inquiring mind wants to know!

Jim, using Ann's computer

[El Pinguino]

Originally Posted by Ann T. Cate

OK, I'll bite: HOW will "none of the above" save my life? An inquiring mind wants to know!

Jim, using Ann's computer

Well, one day when the crew ask you how you are going to get out of some pickle you can just say 'Well, none of the above worked in the exam room so lets just try that again'... nope ... doesn't make sense to me either....

[cal40john]

Teaching beach cat sailing I always include the word apparent or true.

A starting point for to shoot for for sailing downwind efficiently is a beam reach apparent wind, this results in a about a 90 degree jibe angle.

The Hobie 20's best upwind vmg angle is about 50 degrees off of the true wind and with 10 knots TWS you sail at 10 knots, so 25 degrees AWA. Bear off 10 degrees AWA to 35 degrees and you're sailing a beam reach true wind.

[goboatingnow]

Thus to me it would now seem ridiculous to define a beam reach as 90 degrees to the apparent wind, it must be true wind. An ice boat might be able to sail on a beam reach at a speed that is close to the wind speed so it might be heading 45 degrees or more down wind. See vector diagram. So beam reach must be to true wind, which would make it extremely difficult to be precise since it is very difficult to know the true wind while sailing and the wind would be somewhat forward of the beam. I would expect that most sailors would sail with the apparent wind at 90 and call it a beam reach. I would have before this.

All sailing directions refer to the wind as experienced on the boat, Since only when stopped can you experience " True " wind. It follows that all wind you experience on the boat is apparent wind. Thats what every boat sails in. it never sails in the " true wind"

[jheldatksuedu]

Originally Posted by goboatingnow

All sailing directions refer to the wind as experienced on the boat, Since only when stopped can you experience " True " wind. It follows that all wind you experience on the boat is apparent wind. Thats what every boat sails in. it never sails in the " true wind"

A definition can be anything, it makes no difference what one can and cannot experience on a moving boat, to define beam reach with respect to apparent wind is ridiculous, you would be on a broad reach or a run losing ground to the wind. Any diagram showing all the points of sail show the boat with respect to the true wind, not a separate wind arrow for each point of sail, that is what would be needed if the directions and points of sail were respect to apparent winds.

[C.Karo]

True wind or direction can only be experienced if you are stationary. If you have movement, it becomes relative or apparent wind. Any Questions? No, forget it. I am finished. I am heading out to get my fill of apparent wind....