I've been re-engineering my rudder connection points and I'm wondering if it is better to have a certain amount of play between the rudders or to have them very tightly linked (assuming that you can align them accurately). Comments, suggestions?
[color]Jake
[color]Nacra 5.2 (2112)
[color]Hobie 18 (mutt)
Jake,
There are tons of ways to reduce rudder slop. The 3 most important parts are the tillercrossbar to the tiller tubes, the rudders to the rudder castings, the rudder pin to the gudgeons. Another important thing is the tiller connection to the tiller crossbar. The tiller connection and the tiller crossbar to the tiller tubes should have their nuts and bolts as tight as possible. Make sure you can still switch the tiller behind the main blocks okay though. When you tighten up the tiller crossbar to tube connections it might not tighten as tight as it should. This can happen for many reasons including worn spacers, bent bolts, stripped nuts and etc. It is a good idea to replace this every few years if you want it tight, it is not too much money so it is worth it. The other option is buy the h-20 tiller connections system but you will most likley be fine with just replacing the old connections with new similar ones.
Another h-18 tip.... the rudder shims keep the slop out at the top of the casting. However a good amount of slop still occurs on the lower part of the lower casting. To prevent this wrap some kind of tape (electrical, rigging or etc) around the lower part of the casting (the bar type things that go on each side of the rudders). This will reduce slop in that area, keep your rudders from getting all scratched up and worn (if they wear it will create even more slop). Make sure the tape is even or it can cause the rudders to become unalinged (if you were to do a lot on one side and very little on the other or etc) also do not put too much or the rudder will get stuck by the tape .
-Todd
I took my slop out of my 17 by making my own spacers. Cut 5 inch circles out of some old Tupperware tops that didn't match anything anymore. They take all the slop out you want and keep the ruddersfrom even touching the rudder castings. Makes it easy to adjust tension without having to bend your castings in the process. The big circles make for easy positioning when installing the wafers too.
Thanks for the input guys. But my question was more along the lines:
Is it better to remove all the slop possible or to leave a little slop in the system so the rudders can self align?
Jake,
It would seem that if the rudders 'self align', then when steering, wave currents, etc. they would self adjust to not be as efficient. The idea is to produce the most lift, with the smallest amount of drag. A sloppy rudder would louse some of it's lift, be it ever so small. I think you should align with the slightest of toe in, and get rid of the most slop. When I've done this on some of my past and current boats, I couldn't truthfully notice better speed, but a big difference in how the helm felt in my hands, and the ease of steering. Add the dimension of mast/rudder rake for a given sail plan and conditions, and it's like night and day, especially with the chute up. No one likes to fight weather helm. I know this aspect wasn't your question, only the slop, but it all kinda goes together.
Todd Bouton
N6.0na +
#111
The newest stock NACRA connector between the tiller crossbar and the rudders requires some "slop". If you take it all out you will not be able to push th rudders over hard.
The old style works like the Hobie 16 and 18.
Yeah - I've seen that system and the old one - not real happy with it. I've made a few parts that reliably (i.e. long term) eliminates all play in the rudder linkage and works beautifully (and considerably cheaper than upgrading to the 'new' nacra system). I haven't decided to offer these commercially but I'm considering it. I just had a tiny thought that maybe the slop was desirable although I couldn't imagine why.
Self Align!? Give me a break! If you wanted your rudders to do anything by themselves, you'd simply turn loose of the tiller.
When you transition from pulling on the tiller, to pushing on the tiller, you have to compress or stretch out all of the available slop before your input has any affect.
Less "play" (slop) means less time and distance (motion) before your input has an effect on the direction that the boat is pointing. Anyone who is aware enough to consider "rudder slop" will soon find that "slop" is all bad and not any good at all.
Bottom Line: Eliminate any play (possible) in all controls.
To answer your question, rudders do not self align any more than the front tires on a car do and for about the same reasons. You want the rudders roughly parallel to balance out the rudders loads and slop works against that.
ALSO
There is one source of rudder slop you probably have not considered, the flexing of the tiller cross bar. I have a Tornado with both an aluminium and a carbon tiller cross bar. With the aluminium cross bar and a fiberglass hotstick, you steer it with one light hand. With the carbon cross bar and tiller, you steer it with 2 fingers
yeah - thanks - I now realize that was a silly question.