Sailing anyone?

exchemist · Jan 26, 2021

Subduction Zone said:
I am not talking about a boat accomplishing this by tacking with the wind. That is following a zigzag course down wind. That can be done and examples were given in the example that I gave. I was asking if a vessel could go say directly South for example in a wind blowing from due North to due South faster than that wind. The vessel would in effect be sailing directly into its own headwind.

Oh I see what you mean. Possibly not then, as the pressure on the sail will drop to zero when the velocity of the sail equals that of the wind.

exchemist · Jan 26, 2021

Meerkat said:
I'm impressed by the idea of a daily swim! I'm 64, still OK with the kayak, though my back doesn't always agree! Walking by the sea feels a lot easier these days, I like to spot seals and porpoises.

Yes the water in the Golfe du Morbihan is fairly cool even in summer but not too bad if you keep moving once you are in. I only swim for 10-15 mins and then back to the beach to warm up and watch the kids playing - and sometimes admire any yummy mummies that may be about. But the swim works up an appetite for dinner, which is always nice.

The terrace at sunset:

Subduction Zone · Jan 26, 2021

exchemist said:
Oh I see what you mean. Possibly not then, as the pressure on the sail will drop to zero when the velocity of the sail equals that of the wind.

This is why it is a bit of a brain twister. One that sailors can appreciate. It can and has been done. A several times and independently. The Wiki article that I linked was only one click away from another that mentions this:

Wind-powered vehicle - Wikipedia

The vehicle designed to do this is of very limited use. It works best downwind and cannot go upwind at all. Well it can be if one changes the gearing rather drastically and changes it from a propeller driven vehicle to a turbine powered one. It works on feedback where the wind pushes the vehicle forwards which drives the propeller. It still hurts my head a bit. It violates no laws of physics since the wind that it interacts with is slowed down relative to the ground, just as a regular sail does.

exchemist · Jan 26, 2021

Subduction Zone said:
This is why it is a bit of a brain twister. One that sailors can appreciate. It can and has been done. A several times and independently. The Wiki article that I linked was only one click away from another that mentions this:

Wind-powered vehicle - Wikipedia

The vehicle designed to do this is of very limited use. It works best downwind and cannot go upwind at all. Well it can be if one changes the gearing rather drastically and changes it from a propeller driven vehicle to a turbine powered one. It works on feedback where the wind pushes the vehicle forwards which drives the propeller. It still hurts my head a bit. It violates no laws of physics since the wind that it interacts with is slowed down relative to the ground, just as a regular sail does.

Ah yes I vaguely recall this thing. But it's not a sail, of course.

Subduction Zone · Jan 26, 2021

exchemist said:
Ah yes I vaguely recall this thing. But it's not a sail, of course.

But it is :"sailing". It is powered only by the wind. And there is not that much difference between a propeller and a sail on a downwind reach. The math for both are the same. A sail is a bit more versatile since it can work as either a propeller or as a turbine. That vehicle's "sail" can only work as a propeller. It cannot go upwind in that configuration. If one turned it around to face into the wind it would only go backwards. Here is an earlier version of it when it was just a bare skeleton and there was no way to hide any skulduggery:

The BUFC, as it was known then, was a big like the Big Bang Theory. The name was taken from a detractor that said that it was just a "Big Ugly F###ing Cart". When it came time for its official presentation along with its sponsors the name was cleaned up a bit along with the chassis.

Martin · Jan 26, 2021

Subduction Zone said:
But it is :"sailing". It is powered only by the wind. And there is not that much difference between a propeller and a sail on a downwind reach. The math for both are the same. A sail is a bit more versatile since it can work as either a propeller or as a turbine. That vehicle's "sail" can only work as a propeller. It cannot go upwind in that configuration. If one turned it around to face into the wind it would only go backwards. Here is an earlier version of it when it was just a bare skeleton and there was no way to hide any skulduggery:

The BUFC, as it was known then, was a big like the Big Bang Theory. The name was taken from a detractor that said that it was just a "Big Ugly F###ing Cart". When it came time for its official presentation along with its sponsors the name was cleaned up a bit along with the chassis.

You really need to feel it. There's no better feeling than a boat with the sails set right, you can feel the power of the wind vibrating through the hull, the tension of the ropes in your hand, and the boat powering effortlessly through the swell. Magical.

Father Heathen · Jan 26, 2021

Of course they would name it something cheesy, unoriginal, and stereptyical as "Patriot".

Mock Turtle · Jan 27, 2021

Brickjectivity said:
That was brutal!

I should say. It appears to have been caused by a failure of some equipment - that allows the sail to spill wind from the sail(s) when a gust happens. Quite remarkable that they perform so well as it is and I doubt many would have envisaged such boats many decades ago.

Mock Turtle · Jan 27, 2021

ChristineM said:
I didn't watch the race, not my thing but it does look exciting for those with an interest.

What really struck me most about the video was the sponsorship, why is Airbus sponsoring team America as opposed to say Boing???

Looking a bit further, it might be that Boeing just hasn't the expertise in this area whilst Airbus apparently has - being involved in previous competitions - design (aerodynamics, wing and hull design), and perhaps materials.

Mock Turtle · Jan 27, 2021

exchemist said:
I was fine in the Laser up to 10knot winds. Above that I was too light to keep the hull flat when going upwind. Dubai had the classic hot country onshore breeze in the daytime, as the land heated and caused the air above to rise, drawing in cooler air from the sea. 11a.m. - noon would be close to flat calm and then the onshore wind would gradually get stronger as the afternoon wore on. I used to try to do well in the first race, because by the third I would be beaten by the heavier sailors. The only time I was first across the line was a day of almost no wind at all: everyone but me was wallowing in the waves and not moving!

I was tempted with a single-hander at one time but the opportunity never arose. The only time I did any of that was on a boating lake or on holiday - once sailing a dinghy-like proa, which was fun.

Mock Turtle · Jan 27, 2021

The video halfway down the page is worth a look to see how these boats operate:

THE AMERICA'S CUP CLASS AC75 BOAT CONCEPT REVEALED

Brickjectivity · Jan 27, 2021

Mock Turtle said:
I should say. It appears to have been caused by a failure of some equipment - that allows the sail to spill wind from the sail(s) when a gust happens. Quite remarkable that they perform so well as it is and I doubt many would have envisaged such boats many decades ago.

And for it to be named American Magic! That hurt.

Sailing anyone?

exchemist

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exchemist

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Subduction Zone

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exchemist

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Subduction Zone

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Martin

Spam, wonderful spam (bloody vikings!)

Father Heathen

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Mock Turtle

Oh my, did I say that!

Mock Turtle

Oh my, did I say that!

Mock Turtle

Oh my, did I say that!

Mock Turtle

Oh my, did I say that!

Brickjectivity

wind and rain touch not this brain