Possibly a major flaw in sailboat design?
 

In contemplating sailboat design I think I have found a fundamental flaw,
that when corrected should yield a great improvement in sailboat
performance.

The flaw is that the keel is put before the rudder. I believe this legacy
continues in modern designs because of accident.

The rudder rightfully belongs in front of the keel, not behind it for
reasons that shall become obvious upon further reading.

Firstly, think of cars and motorcycles. Are they steered by rear wheels?
Mostly not and with good reason, the steering is better done by the front
wheels.

In making a turn, the front mounted rudder would direct an increased water
flow to one side of the keel which would increase the effectiveness (lift)
of the keel - keep the boat upright , the sails would have more power, the
boat less leeway and the turn executed much more quickly.

In heavy seas, the forward mounted rudder would provide greater stability
and control because of its beneficial redirection of water to one side of
the keel.

Docking and tight maneuvers would also be much easier because the bow is
steered, rather than the stern.

Under power, the propeller would be many times efficient. The rudder would
not be blocking the thrust of the propeller nor inefficiently redirecting
it.

The rudder could be configured to alter the characteristics of the bow wave
which would increase the hull speed and overall speed of the boat.

Just like railroad tracks are the width of a horse's ass, rear mounted
rudders are the result of the legacy of dry helmsman. In these modern times
it's very practical to put a rudder under the bow and enjoy the increased
performance benefits.

Possibly a major flaw in sailboat design?
 

On Thu, 4 Dec 2008 11:24:44 -0700, "Charles Momsen"
wrote:

In contemplating sailboat design I think I have found a fundamental flaw,
that when corrected should yield a great improvement in sailboat
performance.

The flaw is that the keel is put before the rudder. I believe this legacy
continues in modern designs because of accident.

The rudder rightfully belongs in front of the keel, not behind it for
reasons that shall become obvious upon further reading.

Firstly, think of cars and motorcycles. Are they steered by rear wheels?
Mostly not and with good reason, the steering is better done by the front
wheels.

In making a turn, the front mounted rudder would direct an increased water
flow to one side of the keel which would increase the effectiveness (lift)
of the keel - keep the boat upright , the sails would have more power, the
boat less leeway and the turn executed much more quickly.

In heavy seas, the forward mounted rudder would provide greater stability
and control because of its beneficial redirection of water to one side of
the keel.

Docking and tight maneuvers would also be much easier because the bow is
steered, rather than the stern.

Under power, the propeller would be many times efficient. The rudder would
not be blocking the thrust of the propeller nor inefficiently redirecting
it.

The rudder could be configured to alter the characteristics of the bow wave
which would increase the hull speed and overall speed of the boat.

Just like railroad tracks are the width of a horse's ass, rear mounted
rudders are the result of the legacy of dry helmsman. In these modern times
it's very practical to put a rudder under the bow and enjoy the increased
performance benefits.


Unfortunately the water deflected by the forward rudder is so
turbulent that it destroys laminar flow over the keel.




OzOne of the three twins

I welcome you to Crackerbox Palace.

Possibly a major flaw in sailboat design?
 

OzOne wrote in message ...
On Thu, 4 Dec 2008 11:24:44 -0700, "Charles Momsen"
wrote:

In contemplating sailboat design I think I have found a fundamental flaw,
that when corrected should yield a great improvement in sailboat
performance.

The flaw is that the keel is put before the rudder. I believe this legacy
continues in modern designs because of accident.

The rudder rightfully belongs in front of the keel, not behind it for
reasons that shall become obvious upon further reading.

Firstly, think of cars and motorcycles. Are they steered by rear wheels?
Mostly not and with good reason, the steering is better done by the front
wheels.

In making a turn, the front mounted rudder would direct an increased water
flow to one side of the keel which would increase the effectiveness (lift)
of the keel - keep the boat upright , the sails would have more power, the
boat less leeway and the turn executed much more quickly.

In heavy seas, the forward mounted rudder would provide greater stability
and control because of its beneficial redirection of water to one side of
the keel.

Docking and tight maneuvers would also be much easier because the bow is
steered, rather than the stern.

Under power, the propeller would be many times efficient. The rudder would
not be blocking the thrust of the propeller nor inefficiently redirecting
it.

The rudder could be configured to alter the characteristics of the bow
wave
which would increase the hull speed and overall speed of the boat.

Just like railroad tracks are the width of a horse's ass, rear mounted
rudders are the result of the legacy of dry helmsman. In these modern
times
it's very practical to put a rudder under the bow and enjoy the increased
performance benefits.


Unfortunately the water deflected by the forward rudder is so
turbulent that it destroys laminar flow over the keel.


Likewise for the alternative arrangement, during any type of turning of the
boat the keel would generate turbulent flow that would destroy laminar flow
about a rudder behind it. Both generalizations may be true in some
instances but not in all instances.

Possibly a major flaw in sailboat design?
 

Front rudder he

http://www.cbtfco.com/

Possibly a major flaw in sailboat design?
 

On Thu, 4 Dec 2008 16:16:23 -0700, "Charles Momsen"
wrote:


OzOne wrote in message ...
On Thu, 4 Dec 2008 11:24:44 -0700, "Charles Momsen"
wrote:

In contemplating sailboat design I think I have found a fundamental flaw,
that when corrected should yield a great improvement in sailboat
performance.

The flaw is that the keel is put before the rudder. I believe this legacy
continues in modern designs because of accident.

The rudder rightfully belongs in front of the keel, not behind it for
reasons that shall become obvious upon further reading.

Firstly, think of cars and motorcycles. Are they steered by rear wheels?
Mostly not and with good reason, the steering is better done by the front
wheels.

In making a turn, the front mounted rudder would direct an increased water
flow to one side of the keel which would increase the effectiveness (lift)
of the keel - keep the boat upright , the sails would have more power, the
boat less leeway and the turn executed much more quickly.

In heavy seas, the forward mounted rudder would provide greater stability
and control because of its beneficial redirection of water to one side of
the keel.

Docking and tight maneuvers would also be much easier because the bow is
steered, rather than the stern.

Under power, the propeller would be many times efficient. The rudder would
not be blocking the thrust of the propeller nor inefficiently redirecting
it.

The rudder could be configured to alter the characteristics of the bow
wave
which would increase the hull speed and overall speed of the boat.

Just like railroad tracks are the width of a horse's ass, rear mounted
rudders are the result of the legacy of dry helmsman. In these modern
times
it's very practical to put a rudder under the bow and enjoy the increased
performance benefits.


Unfortunately the water deflected by the forward rudder is so
turbulent that it destroys laminar flow over the keel.


Likewise for the alternative arrangement, during any type of turning of the
boat the keel would generate turbulent flow that would destroy laminar flow
about a rudder behind it. Both generalizations may be true in some
instances but not in all instances.


keel has already had the benefit of laminar flow in the conventional
arrangement.




OzOne of the three twins

I welcome you to Crackerbox Palace.

Possibly a major flaw in sailboat design?
 

On Thu, 4 Dec 2008 16:23:48 -0700, "Charles Momsen"
wrote:

Front rudder he

http://www.cbtfco.com/


Yep, on a big big boat so flow is not efected over keel as vortices
shed from the forward rudder are outside of the turning radius




OzOne of the three twins

I welcome you to Crackerbox Palace.

Possibly a major flaw in sailboat design?
 

Ever seen a fish with forward rudder?
Philip C Bolger was the first to expiriment with the concept (at least in
modern history).

Possibly a major flaw in sailboat design?
 

"jlrogers±³©" wrote:
Ever seen a fish with forward rudder?
Philip C Bolger was the first to expiriment with the concept *(at least in
modern history).

One his more interesting experiments/essays... actually he tried it
twice, first time on a boat with a sharpie hull and an experimental
double-luff full-batten main. This boat was very difficult to sail and
was an unmitigated failure (one of the best things about Bolger is he
tells what he's tried that *doesn't* work); but he thought the forward
rudder had possibilities and tried it on another boat of well tried
design.

Fresh Breezes- Doug King

Possibly a major flaw in sailboat design?
 

"Charles Momsen" wrote in message
...
In contemplating sailboat design I think I have found a fundamental flaw,
that when corrected should yield a great improvement in sailboat
performance.

The flaw is that the keel is put before the rudder. I believe this legacy
continues in modern designs because of accident.

The rudder rightfully belongs in front of the keel, not behind it for
reasons that shall become obvious upon further reading.

Firstly, think of cars and motorcycles. Are they steered by rear wheels?
Mostly not and with good reason, the steering is better done by the front
wheels.

In making a turn, the front mounted rudder would direct an increased water
flow to one side of the keel which would increase the effectiveness (lift)
of the keel - keep the boat upright , the sails would have more power, the
boat less leeway and the turn executed much more quickly.

In heavy seas, the forward mounted rudder would provide greater stability
and control because of its beneficial redirection of water to one side of
the keel.

Docking and tight maneuvers would also be much easier because the bow is
steered, rather than the stern.

Under power, the propeller would be many times efficient. The rudder would
not be blocking the thrust of the propeller nor inefficiently redirecting
it.

The rudder could be configured to alter the characteristics of the bow
wave which would increase the hull speed and overall speed of the boat.

Just like railroad tracks are the width of a horse's ass, rear mounted
rudders are the result of the legacy of dry helmsman. In these modern
times it's very practical to put a rudder under the bow and enjoy the
increased performance benefits.


Sounds logical but, unfortunately, it's not. Why? Because a forward rudder
is inherently unstable. How many rockets have you seen with the tailfins on
the front? Space Shuttle doesn't have the rudder on the front. Airplane? No.
Not even a canard airplane has a forward rudder. Fore and aft directional
stability is paramount. You might be able to gain a wee bit of efficiency in
steering with a forward rudder but it will always try to become an aft
rudder - the more so the higher the velocity. And don't say air and water
are two different things. I know that but a fluid is a fluid is a fluid and
air is considered a fluid when things operate in it at sufficient velocities
so air analogies are valid

I hope this helps.

Wilbur Hubbard

Possibly a major flaw in sailboat design?
 

wrote in message
...
"jlrogers±³©" wrote:
Ever seen a fish with forward rudder?
Philip C Bolger was the first to expiriment with the concept (at least in
modern history).

One his more interesting experiments/essays... actually he tried it
twice, first time on a boat with a sharpie hull and an experimental
double-luff full-batten main. This boat was very difficult to sail and
was an unmitigated failure (one of the best things about Bolger is he
tells what he's tried that *doesn't* work); but he thought the forward
rudder had possibilities and tried it on another boat of well tried
design.

Fresh Breezes- Doug King

It was tried here in 2006:

http://www.mediterraneanavenue.com/F...likeButter.pdf

Some benefits are mentioned.

Possibly a major flaw in sailboat design?
 

Any considerations that the center of drag would be ahead of the center of
mass in a forward mounted rudder system?

Possibly a major flaw in sailboat design?
 

"Charles Momsen" wrote in message
...
Any considerations that the center of drag would be ahead of the center of
mass in a forward mounted rudder system?



That's what I just said (inherently unstable) but, of course, I said it more
brilliantly.

You're welcome.

Wilbur Hubbard

Possibly a major flaw in sailboat design?
 

Charles Momsen wrote:
In contemplating sailboat design I think I have found a fundamental flaw,
that when corrected should yield a great improvement in sailboat
performance.

The flaw is that the keel is put before the rudder. I believe this legacy
continues in modern designs because of accident.

The rudder rightfully belongs in front of the keel, not behind it for
reasons that shall become obvious upon further reading.

Firstly, think of cars and motorcycles. Are they steered by rear wheels?
Mostly not and with good reason, the steering is better done by the front
wheels.

It depends on what you wish to accomplish, there are many vehicles with
rear wheel steering, usually relatively slow moving, (and aren't
sailboats relatively slow?) like forklifts and other machines that move
material and require great maneuverability.

Cheers
Martin

Possibly a major flaw in sailboat design?
 

"Charles Momsen" wrote:
It was tried here in 2006:

http://www.mediterraneanavenue.com/F...likeButter.pdf

Some benefits are mentioned.

Heck, there were America's Cup boats with forward rudders in the
1980s, and long before that. I remember a guy who raced Fireballs back
in the 1960s who built a Fireball with "turret daggerboards" which was
a set-up very similar to modern cassette rudders. The poblem he had
was the loading on a fast planing dinghy exceeded commonly available
home-brew materials back then. Too much deflection in any control
linkage he could build made it impossible to control it finely enough.

Plus the Fireball is a complex boat to sail, givng the skipper & crew
yet one more task to concentrate on was not an improvement.

As for controlling canoe-like hulls by balance, check out the St
Lawrence skiffs.

http://books.google.com/books?id=axf...esult#PPA58,M1

or
http://tinyurl.com/6dupkp

The "Rudder Like Butter" might be nice but is it really an improvement
on "No Rudder At All"?

Fresh Breezes- Doug King

Possibly a major flaw in sailboat design?
 

wrote in message
...
"Charles Momsen" wrote:
It was tried here in 2006:

http://www.mediterraneanavenue.com/F...likeButter.pdf

Some benefits are mentioned.

Heck, there were America's Cup boats with forward rudders in the
1980s, and long before that. I remember a guy who raced Fireballs back
in the 1960s who built a Fireball with "turret daggerboards" which was
a set-up very similar to modern cassette rudders. The poblem he had
was the loading on a fast planing dinghy exceeded commonly available
home-brew materials back then. Too much deflection in any control
linkage he could build made it impossible to control it finely enough.

Plus the Fireball is a complex boat to sail, givng the skipper & crew
yet one more task to concentrate on was not an improvement.

As for controlling canoe-like hulls by balance, check out the St
Lawrence skiffs.

http://books.google.com/books?id=axf...esult#PPA58,M1

or
http://tinyurl.com/6dupkp

The "Rudder Like Butter" might be nice but is it really an improvement
on "No Rudder At All"?

Fresh Breezes- Doug King

Great Information Doug!

Possibly a major flaw in sailboat design?
 

"Charles Momsen" wrote in message
...

What is pitch?
Propeller pitch is the theoretical forward movement of a propeller for one
revolution, assuming that there is no prop slip. For example, a 21 pitch
propeller will theoretically move 21 inches for every revolution. Propeller
slip occurs with every propeller, but the amount of slip varies depending on
propeller design. More aggressively and efficiently designed propellers will
slip less.

When selecting a propeller pitch for your boat, it is important that the
propeller runs at the upper end of your engines wide-open-throttle RPM
range. If you want your RPM's to increase, go down in pitch. To decrease
RPM's, go up in pitch. As a general guide, for every 2" of pitch, RPM's will
change approximately 400 RPM's.

For water sports or extra people on board, you should generally drop 2" of
pitch to help compensate for the added weight and drag on your boat. It
makes a noticeable difference in your boat's hole shot, fuel efficiency,
RPM's, and overall performance. You should ALWAYS carry a spare propeller on
board, and if you're into water sports or occasionally load the boat with
extra people, a spare prop with a lesser pitch is a good idea. When thinking
a propeller pitch, compare it to a gear on car - lower gear, higher RPM's.

The same pitch from different manufacturers will run slightly different
RPM's due to a difference in blade design. Speed differences among the same
pitch from various manufacturers will vary even more. For example a 17 pitch
from one brand could run up to 7 mph faster than a 17 pitch from another
brand.

Pitch is the 2nd two digits that are listed in a propeller item description
(14-1/4 x 19, 19 is the pitch, 14-1/4 is the diameter)



--------------------------------------------------------------------------------

What is diameter?
Propeller diameter is distance across the imaginary circle that a spinning
propeller makes. It can be easily determined by measuring the distance from
the center of the hub to the tip of one of the blades and multiplying that
number by 2.

Diameters between different propeller manufacturers may vary slightly. For
example for a V6 outboard application, Turning Point uses a 14-1/4" diameter
where a different manufacturer may use a 14-1/2" diameter. This small
variance does not affect your performance as much as the pitch and overall
design. However, larger diameter propellers - 15" or 16" diameter - are
designed for larger boat applications - 23 ft +, and are not ideal for 15" -
22" foot run-a-bouts. These larger boats need more blade area to push more
water.



--------------------------------------------------------------------------------

What is rake?
Propeller rake is the degree that a propeller blade is angled in relation to
the hub. Props with higher rake typically have better speeds and greater
lift. The better performing propellers typically have between 20 - 30 degree
rake angles.




--------------------------------------------------------------------------------

What is cupping?
Propeller cupping is the curved lip at the trailing edge and/or tip of the
propeller. Cupping helps the propeller to get a better grip in the water for
better holding at higher trim and on turns. Cupping also increases the
efficiency of a propeller and can result in higher top end speeds when
properly designed.



--------------------------------------------------------------------------------

What are vent holes?
Vent holes are holes behind each blade designed to aid in the hole shot of a
propeller. When accelerating from neutral, these holes allow some exhaust
bubbles to flow through and flood the blades. The prop is then spinning
through more turbulent water, thus gaining RPM's and speed more quickly.
After approximately 1000 RPM's, the exhaust flows rapidly enough that is
will bypass the holes and flow through the hub, eliminating any further
slippage from the holes.

This performance feature can only be found in stainless steel propellers.
However Turning Point is the only one to offer this feature in aluminum
propellers as well.