Tandem is useless without a rudder. A skinny rudder is just not effective enough to keep the boat straight all the time without constantly adjusting the rudder. I did a little experiment and it worked. See pic here: http://tinyurl.com/frvnf
If there are mechanical engineers on this board, how would you make this modification more appealing?
gee, I dunno
that’s kinda pretty the way it is
Way too much drag…
…on your addition. Much better to go to a wider rudder blade, that will give you the surface area you need with less drag.
Nice job though.
May be ture.
– Last Updated: Oct-01-06 2:22 PM EST –
but my top speed went from 4.9 mph without this add-on to 5.4 mph with it. Go figure.
bbbKayak rudders have been getting smal-
ler and smaller for some time. This trend looks great, but unfortunately is very inefficient.
The fix you are looking for is simply to replace the rudder blade with one that is the proper size and shape for the job you want done.
Look at a Kruger rudder blade. http://krugercanoes.com/prod01.htm Simple in design. Easy to make. Very, very efficient.
If you make your own blade do not forget to make it balanced for even better performance. Harder to do is a foil shaped cross section, but it adds even more efficiency. The Kruger rudder blade is not balanced or foiled.
:^)
Mick
Correction strokes waste far more energy
that a proper rudder. All you are doing is putting more of the energy you expend to propulsion and less to steering.
:^)
Mick
Blade
The original blade shape looks terrible. A flat plate tapering to a point like that would probably stall at the slightest angle of attack. Using the rudder – or even being in crossing seas – probably gave you a lot of drag and not much turning effect.
For a more elegant modification, you could bolt or rivet through the exisisting blade instead of bolting fore & aft. This would let you shape a cleaner profile.
Just by eye, I’d think around 1 1/2 times the root chord for the full length of the blade would be about right – something like this:
http://www.seawardkayaks.com/prodproductsview.aspx?key=4131&idProduct=4131
Pay attention to how the blade area relates to the pivot axis. More area aft of the pivot axis increases the self-centering tendancy, but also increases pedal effort and torque on the system components.
?
Thanks for the link. Where does it say they sell rudders? The order form has no such item.
Blade
Thank for the tip. I can prabably build it up with fiber glass and epoxy.
Try Calling Patrick
at ONNO paddles. I think I remember reading about a new carbon rudder blade made in a foil shape that he has developed.
Mark
Looks like you could turn on a dime
I kind of agree with Grayhawk that it would create a lot more drag.
I wish I had something like that on my Sealine for the bouy turns in yesterdays race.
Cheers,
jackL
They do not say, but probably will, if
you are willing to pay enough. I sent you there for an example of size and shape.
However, if you just want an oversized alumimun rudder blade grab an old sign and cut one out. An improved one if you balance it, etc.
:^)
Mick