Rudder Assembly

Wheel, tiller and autopilots
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kjay
Posts: 149
Joined: Thu Oct 26, 2006 2:03 am
Location: brisbane

Rudder Assembly

Post by kjay » Fri Jul 03, 2009 3:24 am

Hi guys,

Not having seen any plans for Peter's cats other than my own Sarah. I am sure i have all the pages, but there appears to be a stack of detail missing so thank goodness for this forum. eg stainless rudder shaft has both 40mm and 50mm dia on the plans (too much detail this time) My question is, I will be using the 50mm shaft, what size pvc conduit did you all use, and what clearance between the ruddershaft and the top and bottom bushes did you all decide on,. and also is it up to the individual to design the means to retain the shaft at the top and to attatch the steering linkages. I can figure the link bar but the length of the steering linkage, is that just determind my the amount of room between the tube and the bulkhead? I do apologise if these questions seem basic but my plans don't contain any of this info.

thanks

John

Sarah 16

Jim
Posts: 691
Joined: Fri May 19, 2006 8:25 am
Location: Cairns

Rudder Assembly

Post by Jim » Fri Jul 03, 2009 7:29 am

Hi John, the only thing I can think of as to why there is reference to 40 and 50 pipe could be "Schedule 40" which refers to the wall thickness but has nothing to do with the diameter and the "Nom diameter" would be 2inches or 50mm.

I can't remember the PVC tube diameter but it was thick wall and would have been about 2 1/2" ID which leaves about 1/4" or 6mm wall thickness for the bushes. I made my bushes out of Vesconite which is about as good as it gets for that job. Very good wearing and does not ingest water like some other synthetic materials. I used 50mm wide f/glass tape and wound it around the outside of the tube, I think 4 times with about 30% overlap. The top and bottom had about 8 or10 layers. The bushes were 200mm long with a lip on one end bored out to suit the rudder shaft with a "snug but free" fit. The tube was bored out in a lathe to suit the O/D of the bushes which were pushed in by hand and tapped in the last 10mm, so a firm fit but not something that is hammered all the way in. The lip on the top end of the bush becomes the stop for the thrust washer which goes between the top of the tube and the thrust surface on the bottom of the tiller. The tiller length I made as long as I could just as you thought. The tiller was bored out to fit over the rudder shaft and the thrust surface was turned at the same time to be square with the mating surface of the thrust washer and the bush, then secured by 2 x 5/16 through bolts with no clearance up and down, but again, not tight. No seals are required as the water level is quite low down and the water acts as a lube in the bottom bush which takes most of the load.



The top of the bush can be seen under the thrust washer.



The hose clamp is to stop the whole lot falling out before the tiller was fitted.











Easy as.

Jim.

kjay
Posts: 149
Joined: Thu Oct 26, 2006 2:03 am
Location: brisbane

Rudder Assembly

Post by kjay » Fri Jul 03, 2009 6:34 pm

Wow, how good is this forum, Jim all your info is invaluable, thank you very much. i can see us chatting a whole lot more before this boat hits the water.

thanks again,

John

kjay
Posts: 149
Joined: Thu Oct 26, 2006 2:03 am
Location: brisbane

Rudder Assembly

Post by kjay » Fri Jul 03, 2009 6:44 pm

Jim the plans reference 40mm shedule 40 stainless steel and next to the drawings there is a sketch showing the rudder profile with 50mm shed 40 s/s shaft, go figure. But with this forums help I am sure any hurdle will be crossed.

thanks

John

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