When I owned a Laser the line (no bungee chord) ran up from to rudder to the tiller and was cleated in place. The cleat is placed on the SIDE of the tiller. I sailed the Laser for 15 years and never had a problem with the rudder popping-up on me.
It took me a few years to figure out the obvious and the solution was literally in front of me all the time.

I also notice that the nut on the pivot bolt frequently comes a bit loose. I thought a locking nut meant it wouldn't come loose via vibration. I suppose a new locking nut would be in order.

Has anyone ever noticed that when we're heeled right over ( and praying not to capsize) that the rudder doesn't have a lot of bite in the water (it may have popped-up without knowing it). I'm thinking of designing a deeper rudder because I wonder if a well tuned factory rudder is deep enough. What are your thoughts?

Robert
Celtic Kiss

I think this cleat should do the trick. I figure we can mount them on the side of the tiller. A tiller mounted cleat would prevent the line from interfering with the sliding hatch.

posted December 19, 2002 11:20 AM            

If your rudder keeps poping up the problem isn't the bungie - its your rig balance. Opposing forces in the water are creating a force that pushes the rudder out...

How does the boat handle when you let the tiller alone? does it head up? bear away? or track straight? You want a bit of wheather helm (heading up) present. If you boat bears away when you let go you need to allow more aft rake in your mast. If it heads up really fast, then you need to bring the rig forward. You need to move the whole rig. For example if you tighten the forstay, loosen the shrouds.

I caution the use of the auto release cam cleat. We too thought it was the end all cleat, until we used it. The reset feature was something we thought would developinto a hassle. The cleat was prone to "ejecting" during my trials.

What size shock cord are you using? We supply 3/8". This provides the proper "tug". Also the braid of the shock cord is unique. It "gives" based on load. The Tie down shock cords you can find at Canadain Tire are not well suited for this.

If you want to alter your rudder you can always do it cheap and dirty by just reversing it. This gives it a straight down profile. We also have a scale drawing of a "new" rudder if you would like. It is just an outline, you would have to work out the details your self. It was the shape I used when I owned and raced CL16 #633. If anybody should ever happen to come across #633 shes a great boat =)

Anyway, this should give you some more things to chew on.

Regards

The boat handles fairly well when I let go of the tiller (given the wind condition). 'Kiss will track straight for awhile and will slowly turn head to wind. As I understand it, that is a built in safety factor during a MOA (man overboard) or when some other trouble is encountered.

My shock chord is 3/8" which I got from the CL dealership in Calgary. I think my problem lies in knowing exactly what kind of tension to have and to know what the lengths of both rope and bungee cord are.

In any event I think I'll get some of those cleats and try them for myself. It's the only way I'll ever really know.

I think I'll take you up on the offer for an outline of an alternate rudder though. Check your e-mail.

Best Regards'

I performed what I refer to as "catalog engineering": I looked at the pictures and copied the main themes.

First, conventional logic is that the underwater plan should be elliptical, like the wing of a World War II Spitfire. Apparently, this produces less drag and generates more lift right down to the tip.

Also, the photos and line drawings suggested that the trailing edge should be vertical and the leading edge follow the elliptical profile. I did not have the nerve to make the entire length of the foil elliptical; but instead, started the elliptical shape about 1/3 of the rudder's length below the waterline. I traced, modelled and recut the blade's head so that it would hang vertical rather than be raked aft.

I used Harold Ginsberg's NACA4GEN program (available on the web) to generate a NASA cross-section. I cheated by incorporating a straight section in the body. So, only the leading and trailing edges are true airfoil shape. The original rudder had only a 3/8" radius at the leading edge and a 1-1/2" taper at the trailing edge. My leading edge is now 1-7/8" long and the trailing edge is 3-3/4" long with about a 1/64" trailing radius to dull the razor edge.

The only difference I detected was that the more vertical rudder was a little lighter on the tiller because of the improved mechanical advantage. The centroid of the foil was now closer to the pivot point on the transom. The new rudder also seemed a little less prone to "popping up".

In the rebuild, I also knocked some meat out of the rudder head to make it lighter.

That was a great post. Cody was kind enough to send me a rough outline of a rudder he did a few years ago. I'll try to incorporate your measurements into the prototype and see what I come up with. Can you provide us a link for the cross section you mentioned? I'll definitely report back on my findings for the camcleat.

Merry Christmas

Robert