Does the distance from the rudder to the stern matter with regards to drag ? Or does it not matter ?
Someone mentioned that the rudder induces turbulent flow,
and
the more forward the rudder, the larger the hull area that would be affected by this turbulence.
Google could not answer this question ! Does anybody know about this effect ?
Submitted by eckhart on Fri, 02/22/2008 - 7:32pm
Eckhart. The rudder drag is tremendous. The only way to counteract this parasitic drag is to continue to paddle with the rudder removed. Once you master the art of steering without a rudder you will be amazed at how much faster you are going.
Oh yeah. And I should also mention that this only works in completely calm conditions Don't try this in the open ocean, some old guy might go flying right past you.
#1 Fri, 02/22/2008 - 8:34pm
I have done rudderless for three days involuntarily. It was very interesting to feel what waves and wind actually do to the boat and what you can try to correct/stabilize.
You are very fast, but, as you say, you also lose a lot of energy with constant corrections.
Based on that, I am sure that it is beneficial to paddle regularly without rudder.
This experience is the background for my question:
since I mounted the regular rudder again, the increase in drag seems to be dramatic.
Some websites state a total of 10 %, Epic claims 2 % ! of added total drag - it surely feels like a lot, to say the least.
In your experience: Does the POSITION of the rudder add to the drag too ? I moved the rudder forward and am at a loss right now to explain whether I feel the drag so much because I paddled without rudder, or because the new rudder position has added drag - which I would not expect.
#2 Fri, 02/22/2008 - 9:44pm
Ecky, now you have to modify the Hurricane stern to more like a Pahoa to counter the extra drag the rudder move caused.
Cheers Rambo
#3 Sat, 02/23/2008 - 2:02am
Rambo, you've got that right. :)
When you start changing a boat, you realize that most ideas are already out there. So a Hurricane should be a little more like a Pegasus, but also have some Zephyr in there, plus some of the Pahoa feel, and of course an ama from the Wainui/Kainalu ... never ending story.
Does it cause extra drag to move the rudder forward ? If so, it would be interesting to know why.
#4 Sat, 02/23/2008 - 4:38pm
I look forward to the day someone creates a retractable rudder that's triggered by foot pressure. Perhaps a spring loaded device that inserts the rudder into the water when pressure from both feet are applied would work.
#5 Mon, 02/25/2008 - 9:18am
Snafblat, we'll call it the penis rudder.
#6 Mon, 02/25/2008 - 9:49am
how about two rudders, one on either side of the canoe about the same spot as a standard rudder configuration, They would be retracted until you added pressure to the pedals, The more you push the pedal the deeper it became and created more steering. sort of like poking on a six man,
#7 Mon, 02/25/2008 - 9:52am
umm isnt that what snafblat just suggested?
#8 Mon, 02/25/2008 - 10:08am
I say move the rudder to the front of the canoe (about 400mm from the bow) and reduce its size. Would be fantastic for downwind.
Rambo
#9 Mon, 02/25/2008 - 1:06pm
Similar, But what I think he suggested was a rudder in the same position as what we are used to, My design would have two rudders, One on either side of the canoe, near the current rudder, The more you push the further it goes into the water. Not an all or nothing, as I think he was suggesting.
Think of it as a little menahune sitting back there steering, Making fine adjustments to the boat.
#10 Mon, 02/25/2008 - 1:09pm
I m not sure that it would make too much sense.
To get the same effect steering, you would have the same drag.
While engaging the rudder, you would have to pierce the surface - not good.
While not engaged, you would not have a rudder nor kiel - only good in calm conditions.
#11 Mon, 02/25/2008 - 1:15pm
Like areo bars on a bike, Not for all conditions or all bikes, But when it's flat they make a huge difference, I'm not sure if it would work, But some day I would love to try it to see, The best inventions are generally the ones that get laughed at the most in the beginning. Think back to when the Hurricane was introduced, Nobody thought it was big enough, that it would be a good kids boat or girls boat, My guess is that that one design has sold more times than all the builders current designs on the market combined.
#12 Mon, 02/25/2008 - 3:42pm
.
#13 Fri, 03/02/2012 - 9:15am
hmmm.. like an old school foot drag longboarding... if you had a fin (it'll be a fin or skeg more than a rudder) on either side operating by pressure which you can work with the cable coming from a pulley from BEHIND the fin (so when you step on the pedal, it controls how much fin comes out...) you can call it turtlehead and color it brown.. poops would love it.
i wonder if it'll work straight up and down, or angled in or out to get maximum benefit.... imagine if it angled in or out, and you stepped on both at the same time, it'll form almost a little hydrofoil.. kind of like the paired pelvic fin of a shark angles out on both sides... or if it angles in, it can form a different effect.. interesting idea.
#14 Mon, 02/25/2008 - 4:47pm
one idea i was kicking around was to have a hydrofoil type assembly in the back instead of a rudder and the pedals would control the roll in either direction, so instead of a rotating rudder which slows the boat down by blocking the water flow in one direction or another. this will just direct the water in either direction... when you surf, you use the pressure on the fins to drive in one direction or another, so this steering mechanism would use the same concept of putting pressure on one side to steer...
#15 Mon, 02/25/2008 - 5:03pm
OceanO
Interesting concept. I think it would have to be like a teeter totter on the deck......as you push the left peddle the left side comes down into the water.....a poke. The rudder/blade could be twisted like a prop so the deeper it sinks the more redirection of water flow resulting in steering. Now whose ready to step up and build it?
#16 Mon, 02/25/2008 - 5:39pm
Talking is fun .. but then reailty hits ...
Slot(s) for them = H U G E drag buckets.
Ducking back behind my rock now ....
#17 Mon, 02/25/2008 - 6:13pm
The shark has quite a bit of rocker. More than a Hurricane.
#18 Mon, 02/25/2008 - 7:50pm
I wouldn't use slots, just a fin on the side, If the tahitians can paddle as fast as they do with fully rudderless boats, a semi rudderless design for fairly flat water is highly probable. I have two rudderless boats being built, maybe these will be good boats to make this happen.
#19 Mon, 02/25/2008 - 8:04pm
If it is for flat water and calm conditions, you are better off rudderless.
A fin on the side will have all the disadvantages of a surface penetrating rudder. The fact that is has to be engaged and disengaged makes this even worse.
I like the idea; we all want to get rid of the tremendous drag of the rudder.
I tend to agree that the only way to do that is not to have a rudder, though.
#20 Mon, 02/25/2008 - 9:15pm
sounds like something else to break
#21 Mon, 02/25/2008 - 9:29pm
Don't these already exist as over the stern kickup rudders on river kayaks and some sea kayaks?
Cheers Rambo
#22 Tue, 02/26/2008 - 3:07am
Here are the the ones I make.
http://www.onnopaddles.com/onnoaccessories.html
The blaeds would be to cool to use for above appendages though.
#23 Tue, 02/26/2008 - 1:24pm
I raced rudderless a few weeks ago and it didn't help that much because despite going faster I also paddled farther. Although I did put a nice ding in my friends boat courtesy of the pointier and super narrow bow of the boat. In flat water though I have found that I am way faster in the Rudderless canoe than I am in my Kaimana. Seems the tahitians definitely know what their doing.
Now if only I could surf the friggin thing.
#24 Wed, 02/27/2008 - 12:26pm