"riverman" wrote in message ...
"Howie" wrote in message
...
On Mon, 10 May 2004 10:48:22 GMT, "Martin Underwood"
wrote:

|This is probably an incredibly naive question, and I apologise if it's a
|FAQ, but it's one of those things that I was pondering on in an idle
moment.
|
|Why is it that on all boats, the rudder is at the back rather than the
front
|of the boat? Is it:
|
|- because a rudder at the front simply wouldn't work properly to steer
the
|boat?
|
|- because a rudder at the back gives greater manoeuvrability, in the same
|way that dumper trucks on building sites have rear-wheel steering whereas
|cars and lorries have front-wheel steering?

It's to do with displacement. A displacement hull is designed to
'fend off' water whilst travelling forwards.
A rudder at the front would stop the displacement hull working
effeciently unless you are travelling in a straight line. So - it
slows the boat down.

Also, Because the boat is designed to go at maximum speed when
going forwards, the water stream passing under and around the
boat is much more stable and reliable as a medium than the water
you have not yet hit! Effectively, the water speed and direction
helps the rudder to do it's job. A rudder hinders the effeciency
of this water stream, this is how it operates. You wouldn't want
the rudder to hinder the water-stream before the hull gets a
chance to move through it!

Sounds intelligent enough and believable, but then explain canard wings on
aircraft...? That's basically a rudder in front.

I also think this question could be given a lot of insight by some sweep
boaters; they have rudders/oars at both ends, and those guys are well
acquianted with steering with one or the other against the current
differential. Any sweep-oarsmen out there?

--riverman

--riverman

A canard true enough is a rudder. It can turn a plane so fast as to
have it lose directional stability and in modern fighters could tear
itself apart.
At speed the canard on aircraft is controled entierly by computer.
This as opposed to the Cesna a friend let me fly . Rudder in the rear
but like the kayak the rudder was not used as much as I thought it
would be.
Control was manual and easily mastered my a relative beginner.

The Front sweep is a low speed maneuver relative to the speed of the
boat in the water. A raft flying down a river often has zero speed
relative to the water.

The rudder in the stern redirects a moving boat in the most
controlable and predictable fashion .
A front cross bow rudder in a sea kayak is a fun way to put a crowd of
beginners into the water.
Control is smooth, simple , reliable and more efficient with the
rudder at the rear of the boat.
Now boat lean and progressive sweep strokes with no rudder is much
more efficient and looses little if any speed when compared to the
drag of a rudder.

Who thought such a basic question would make us think?