Naca Foils for self steering
 

One of the big problems with wind vane steering is that they don't
work well below 3 knots or so because the foil in the water doesn't/
can't generate enough lift to move the steering device, be it tiller or
wheel.
So, I'm wondering how one would design and build a foil to maximize
power through water at low speeds. Would longer or wider or fatter be
better? Would a wing on the bottom help at such low speeds?
Impossible dream?
Gordon

Naca Foils for self steering
 

On Mon, 29 Mar 2010 13:44:02 -0700, Gordon wrote:


One of the big problems with wind vane steering is that they don't
work well below 3 knots or so because the foil in the water doesn't/
can't generate enough lift to move the steering device, be it tiller or
wheel.
So, I'm wondering how one would design and build a foil to maximize
power through water at low speeds. Would longer or wider or fatter be
better? Would a wing on the bottom help at such low speeds?
Impossible dream?
Gordon

You can make a wind vane steer at practically any speed by changing
the area of either the wind-vane or the rudder (the part in the water)
the problem is that if you increase the area in either areas it
becomes overly sensitive when the wind gets up.

I had a Hydro-vane installed on my last boat, see
http://www.hydrovane.com/OurProduct.html

It directly steers the boat and the rudder was effective nearly to a
stop (although it turned pretty slow at that speed :-)

You will note that the rudder is a foil.

In general aerodynamics and hydrodynamics are much the same, taking
into consideration viscosity and speed, etc. The wings you mentioned
work by generating lift albeit downward rather then upward :-)

Naca Foils for self steering
 

I had a Hydro-vane installed on my last boat, see
http://www.hydrovane.com/OurProduct.html

It directly steers the boat and the rudder was effective nearly to a
stop (although it turned pretty slow at that speed :-)

You will note that the rudder is a foil.

In general aerodynamics and hydrodynamics are much the same, taking
into consideration viscosity and speed, etc. The wings you mentioned
work by generating lift albeit downward rather then upward :-)


.
Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Interesting unit. What happens when you go in reverse?

Naca Foils for self steering
 

On Tue, 30 Mar 2010 08:34:46 -0700, Gordon wrote:


I had a Hydro-vane installed on my last boat, see
http://www.hydrovane.com/OurProduct.html

It directly steers the boat and the rudder was effective nearly to a
stop (although it turned pretty slow at that speed :-)

You will note that the rudder is a foil.

In general aerodynamics and hydrodynamics are much the same, taking
into consideration viscosity and speed, etc. The wings you mentioned
work by generating lift albeit downward rather then upward :-)


.
Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Interesting unit. What happens when you go in reverse?

Well, you seldom go into reverse while the vane is steering the boat
:-)

But more seriously, while maneuvering under power you lock the
auxiliary rudder straight ahead by inserting a locking pin.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Naca Foils for self steering
 

In article , Gordon wrote:

One of the big problems with wind vane steering is that they don't
work well below 3 knots or so because the foil in the water doesn't/
can't generate enough lift to move the steering device, be it tiller or
wheel.
So, I'm wondering how one would design and build a foil to maximize
power through water at low speeds. Would longer or wider or fatter be
better? Would a wing on the bottom help at such low speeds?
Impossible dream?
Gordon

There is a database of NACA foils at
URL:http://www.worldofkrauss.com/foils/search?contains=hydro. It's
searchable and you can specify lift and lift-to-drag ratio. If you
understand the physics of it all I'm sure it'll be elementary, dear
Watson.

Justin.

--
Justin C, by the sea.

Naca Foils for self steering
 

Justin C wrote:
In article , Gordon wrote:
One of the big problems with wind vane steering is that they don't
work well below 3 knots or so because the foil in the water doesn't/
can't generate enough lift to move the steering device, be it tiller or
wheel.
So, I'm wondering how one would design and build a foil to maximize
power through water at low speeds. Would longer or wider or fatter be
better? Would a wing on the bottom help at such low speeds?
Impossible dream?
Gordon

There is a database of NACA foils at
URL:http://www.worldofkrauss.com/foils/search?contains=hydro. It's
searchable and you can specify lift and lift-to-drag ratio. If you
understand the physics of it all I'm sure it'll be elementary, dear
Watson.

Justin.


Thanks for the link. I've been studying other pages and I think I now
have a fair understanding of what is needed.
Gordon

Naca Foils for self steering
 

In article , Gordon wrote:
Justin C wrote:
In article , Gordon wrote:
One of the big problems with wind vane steering is that they don't
work well below 3 knots or so because the foil in the water doesn't/
can't generate enough lift to move the steering device, be it tiller or
wheel.
So, I'm wondering how one would design and build a foil to maximize
power through water at low speeds. Would longer or wider or fatter be
better? Would a wing on the bottom help at such low speeds?
Impossible dream?
Gordon

There is a database of NACA foils at
URL:http://www.worldofkrauss.com/foils/search?contains=hydro. It's
searchable and you can specify lift and lift-to-drag ratio. If you
understand the physics of it all I'm sure it'll be elementary, dear
Watson.

Justin.


Thanks for the link. I've been studying other pages and I think I now
have a fair understanding of what is needed.
Gordon

You're very welcome. The physics of it is way beyond what I learnt at
school, so I'm *really* glad you didn't come back and ask any questions!

Justin.

--
Justin C, by the sea.