Diameter of rudder shaft Ocean 47

[blue-max]

Maybe some can answer my question. I need to  know the diameter of the rudder shaft on my boat because I wish to  connect  an autopilot  drive  unit. ( The steering quadrant is fixed half way up the shaft making it difficult to fabricate a strong fitting for the drive unit bracket. So  I want to  install the drive unit lower than the quadrant with an arm coming off the shaft. It would be good to  have that piece before I set off to  the boat in Turkey as sourcing that piece could take up  much  time. My idea is to  adapt  and engine connecting rod ( old truck engine with a fat crankshaft and long stroke.
I should think  the shaft diameter for the Ocean would be the same for single wheel  designs with similar sized boats from the  J & J stable.

[Yngmar]

Probably can find the plans on the Jefa server, but you still have to measure as the shafts have stepped diameters depending on which point you want to attach to.

https://jefa.com/ftp/old_boat_spare_parts/Bavaria/

Also, not sure connrods can handle angular forces very well, they're kind of designed the other way. If it's big enough though

[blue-max]

I think you are right about the stepping Jeffa shows the bearing as 50mm diameter  which does not look right.  I was hoping to  use a con rod from an old truck engine. Car engines seem to have short strokes compared to older engines and it will need a long stroke to minimise effort and to assist accuracy. Should be strong enough  but will need a screw in the centre to pin it to the the shaft (like the quadrant)   

[symphony2]

jefa do a range of steering arms either already bored to size or pilot bored.
jefa.com/steering/products/rackandpinion/tillerlever.htm

[blue-max]

Thanks for the reference - I think I did look it up some time ago. For what is a simple lever/clamp I was surprised  by the prices.

[symphony2]

Just a sign of the times - but they work.

[kavok]

Jefa assure correct value/efficace for money.
But yachting never wase a cheaper activity.
In the 3 last years even less.

[blue-max]

I think the diameter of the rudder shaft is 63 mm. Any comments?

[Yngmar]

Mine was also exactly 63mm. The Jefa plans were 64mm. I had made the mistake of ordering from the plans...

The stamp on the rudder bearing housing (under the antifouling) turned out to be "JP3", which was the previous company supplying rudders to Bavaria before switching to Jefa. So different manufacturer, different size it would seem.

But that's the diameter at the bottom where the bearing sits. The shaft is tapered in several steps upwards and where the autopilot sits it wasn't 63mm anymore.

[blue-max]

Good to know. I shall just have to wait until I can get back  on the boat and work it out from there.