I use 5mm Spectra through roller bearing blocks. I have Spectra mainly because the local marine business only stocks Spectra, it's best you know! 6mm double braid would be more than adequate. I have a twin cleat system on the end of my tiller so I can adjust any slack out individually or if I want to adjust overall slackness just lift up the tiller slightly.

Its more about reducing friction through turning blocks and reducing bulk if you have wheel steering. The breaking strain is not really a concern.

QLDCruiser said..
How about Dyneema Ocean 12? This is single braid dyneema (=spectra). 4mm has a breaking strain of about 2t, more than 8mm double braid. But I'm sure the 3mm, at 1.1t, would be plenty strong enough. It is incredibly light, has low stretch, flexible and slippery, and very easy to splice.

http://www.ropegalore.com.au/4mm-dyneema-rope-sold-per-metre-free-delivery/

I'm not familiar with the application - if you need to apply significant tension by hand, this stuff would be no good on its own although you may be able splice on a tail of double braid.

Here is a video of my Fleming on its previous host, an S&S34 mid Atlantic. You can see the control lines working to move the tiller. MB has a tiller.

cisco said..

MorningBird said..

MB has a tiller.

I am so glad to hear that. Is it as disgustingly phallic as the one in the video??

Would not have noticed that till you mentioned it! Chain link is quick and easy but there are times when a slight variation in weather helm needs only one side adjusted slightly. Two jam cleats make this much easier.
This is my video. The two jam cleats are near the end of the tiller. There are 3 turning points for the control lines so I can alter the ratio. Normally I use the centre one but sometimes when sailing directly down wind I use the bottom one which gives a faster reaction time at the expense of less power. In the video the twin SS rods for the vanes tiller have been changed for a twin SS tube set up now after the original set up suffered some severe bending on a heavy breeze day.

cisco said..

MorningBird said..

MB has a tiller.

I am so glad to hear that. Is it as disgustingly phallic as the one in the video??

More so. Calm down, its legal not compulsory.