sail aerodynamics

Roger Taylor

An eccentric Briton? No, a realistic and rational man.

 

ATTN CARLOSK2:
Would you PLEASE take you ramblings over to your own subject thread !!

You are NOT contributing useful material to this one !!

 

Benford design has this little gem of a sketch at the head of this page -> Benford Design Group https://www.benford.us/index.html?cruisingsail/

If I'm seeing this correctly, the main mast is a square rig with the following flying from it.

* A triangular 'square' sail
* A triangular top sail
* Two genoas

Now obviously anything you throw up a mast will work for some value of 'work' due to drag, but could this be made to work as anything other than a downwind windjammer?



Are you even ready to discuss the mizzen?

 

It is unusual for the whole crew to be ejected. Wearing a harness would prevent that. If a boat gets home safe without the crew, there is probably no problem with the yacht. The bad behavior was from the crew.

 

I think the answer to the question posed in post #978 is "scarcely".For any rig to go upwind it usually requires a tight luff to maintain an effective sail shape and I can't imagine that happening.I suspect that the design was aimed at those who like the idea of an "old time" aesthetic and who would have a substantial engine down below to allow them to get to places where their design selection can be admired by those with similar tastes.I would doubt that any actually got completed with such a rig and I don't suppose there would be a stampede of volunteers to ascend those ratlines when reefing is needed.It might make a nice picture on a daydreamer's wall.

 

The funny thing about this thread is that it starts like this: - I don't want the typical, correct answer, but a different one

A simple exercise

With 10-12 knots of wind, position the sailboat at 30° AWA with only the mainsail

Sail like this for a while

Then hoist the StaySail... Woooow

A mysterious Force appears

It's low pressure, suction, on the leading edge of the StaySail

and the amount depends on the trailing edge of the MainSail

But

But this magic of 1 magnificent Wing built with 2 elements (StaySail + MainSail) refers to

(A) Upwind and
(B) a Wind range and an Angle of Attack

If the leading edge of the StaySail is so valuable ... then logically you'd want a huge headsail and a small mainsail acting as a 'flap'

Yes, if you want to win a summer regatta in the 1970s-1990s

But that way you have a terrible rig from a versatility standpoint

In other words: different winds and different angles.

The most logical thing in a rational world ... in a distant galaxy ... would be to see:

many tiny sailboats, some with fractional 3/4 rigs MainSail = 2 x StaySail, and others with Chinese rigs

and on the other hand, larger sailboats with two masts

To put things on top another things

In this world, which is precisely the planet of the apes, we have recently witnessed the pinnacle of this industry:

a gigantic motor vessel...

on top ... a 75-meter (!) high mast, and to add insult to injury, positioned at the bow (approximately 40% LWL) just like in 1860, and for even more fun, large sails furled at the bow.






the grandfather...
and his grandson

 

1 Ton, 1917

Learning to fly in the U.S. Army https://www.gutenberg.org/cache/epub/72902/pg72902-images.html

my proposed Peace Treaty with the naval architects is as follows:

vessels from 30 tons to 1 million tons for you, and furthermore, although they can generate considerable lift and fly, we'll give you the small motorboats.

and the sailboats of 10 tons and below for aeronautical engineers and model aircraft enthusiasts.